How To Diagnose and Repair Problems with the Torsion Bars on Your Imperial

Imperial Home Page -> Repair -> Suspension -> Torsion Bars

Question from Mike (1967):

I felt my Imperial was sitting a bit low in the front, so I looked in the FSM, it gives dimensions for height adjustments. I turned the passenger side torsion bar adjusting bolt a couple of turns (it has about 1/2+ of it's adjustment left) then went to the drivers side , found the adjustment bolt turned all the way in-no adjustment left. ( the rubber rebounds on that side are completely smashed to pieces, like it's been bouncing on it for a while) I figured that like old leaf springs, that right side bar has got old and tired and needs to be replaced. I got the Mopar part #'s and went on parts voice found some bars, ended up talking to Mr. Mitchell , he said he would like to sell me some bars, but it wouldn't solve the problem, he said torsion bars don't wear out , he said something else is probably broken. My question is, is it "normal" or right for the drivers side bar to be adjusted all the way and the pass. side bar bolt only 1/3 to 1/2 ? , do I have a problem here, if so could it be a cracked weld, bad bushing or a broken/extremely worn part ? any advice on removing a torsion bar or is this a job best left to a suspension shop.

Replies:

From Norm:

A very likely scenario is that either the adjusting bolt or the threaded nut that it interacts with is stripped. The torsion bar is tensioned or released as a result of the bolt's action on the nut, which moves the bar in one direction for more tension, the other for less. Corrosion or mechanical stripping or the bolt and/or nut could be culprits.

From Brad:

Also check the rear mounting bracket. Be sure the bar is being held in the correct position there.

From John:

I went through all this on my '65. I was convinced I needed a new torsion bar, so I got a pair from a '66 in a salvage yard, along with the mounts and adjusting bolts. Took the whole lot to the suspension shop. They installed a new lower control arm bushing, and replaced my old (stripped) adjusting bolt and put the new torsion bars back in the trunk.

Problem solved! Moral of the story: check the adjuster and the bushing.

From Bob:

 

I just read my September issue of High Performance Mopar and they have a story about torsion bars in this issue. They said that there is a left and a right side for these bars and if you get them mixed up you wont get the car to set right.

Follow-up from Doug:

Torsion bars only twist one way. So naturally left and right torsion bars differ from one another. You must label them when removed as to not install them on the wrong side. A wrongly installed torsion bar is downright dangerous. Not only does the car not sit right, but the torsion bar will eventually snap because the weight of the vehicle is forcing it to twist the wrong way (especially when cornering). That said, torsion bars are a great suspension system easily outlasting a conventional coil spring.

Question from Bob (1968):

I am about to recheck my bars to make sure they are on the side that they belong on. I am not sure what side is odd or even I have lost the magazine that had the story on the bars. Right now I have the bars adjusted as far as they will go and I am still bottoming out when I go over bumps in the road.

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From Demetrios:

How are your shocks?

To check the ride height, compare your car to one of the cars in the website (it may be best to look at the color brocure). If your car sits too low, you should be able to tell by comparing the other pictures. If it does not sit too low, then your shocks may be the problem. If it does sit too low, I am wondering if you can pull the T-bars off the cross member and move the hex one more flat to "wind" the T-bars more.

There are no head light switches out there. For all you 67-68 Imperial owners, you need to install a relay to protect your switch from the high current (the switch only operates the relay, and all the current for the head lights goes through the relay rather than the switch, the relay is usually installed on the cross member above the radiator). Don't wait until the switch is acting up (however, even then, the relay may help).

From Paul:

There is something very wrong with your car. The torsion bars can be adjusted to make the front of the car sit three feet off the ground. I would suspect that the torsion bar anchor bolts are either stripped or otherwise not functioning. I had a problem like that with one side of my '65 Imperial (the old Sears Service Center Story). Finally, the anchor bolt fell out (or broke off) completely and I took the car to the frame shop. They were the ones that diagnosed the anchor bolt problem.

You should have your car checked out professionally by a shop that understands Chrysler front suspensions from that period.

From Pete:

In "Chrysler World" a RH side part always ends with an even number and a LH side part with an odd number. Further, the RH/LH determination is made according to the part location as viewed from the driver's seat.

Torsion bars have the last 3 digits of the p/n embossed into the ends of the bars. Look for 891 or 934 or whatever. There may even be an "L" or "R" after the number - I think there is _ but I won't swear to it.

It sounds like you are off "one hex" on your installation. I could describe the process for correcting this on a "regular" Chrysler but not on an Imperial.

Follow-up question from Bob:

I went over to garage today and removed the adjusting bolts on the t-bars. On the left side I have an half inch between the adjusting bolt and the pad that it rest on to raze the car. On the right side I have about three quarter of an inch. Could this be my problem with bottoming out. I was wondering if I need to remove the bars and move the pads to the bolt adjusters.

Reply from William:

If the bars do not have enough preload on them, which will result in lower ride height in the front, the spring rate will be softer than what it should be. The Chrysler service manual mentions taking measurements from two places on each side of the front suspension, which generates the height spec they use in the service manual. In later years, the spec was changed to the dimension between the lower control arm and the bottom of the rubber bumper that contacts it when the suspension is compressed. With torsion bars, the less preload they have the softer the spring rate and vice versa.

Visually, the rocker panel of the vehicle should be parallel to the flat road surface. If you extent an imaginary line from the rocker panel through the wheel covers, the front and back should "hit" the center section of the wheel cover in the same places. If, per chance, the rear springs have sagged, this particular exercise might not be entirely accurate, but you can then use the advertising pictures of the day for Chryslers or Impeials for an idea.

Other than that, shock absorbers can have an effect too, but if the spring is not strong enough or the speed is way too fast for the terrain, bottoming out will happen. My experience has been that if the bars are set to specs and the shocks are good HD units (although current shocks might not be as good as the older Monroe Super 500s or Gabriel Striders!), the cars should have greater capabilities than anything else in their size class.

Get a Chrysler manual for those years and check the basic positioning of the bar in the rear housing. You should be able to do this without disassembling anything, if I recall correctly. If the indexing is correct and one side takes more preload to hit the specs, then it might be getting ready to have a problem. If removing/installing the bars, use Chrysler-specified tools to remove them as others might damage the bar! Seems like I saw where someone was repro-ing them (in one of the recent Mopar mags or Mopar Collectors Guide).

Another question from Bob:

Tonight I pulled the isolator bar out of the Imperial. I then tried to turn the bars a little to mate them to the adjusting bolts but they would not move do I need to loosen the nuts that hold the lower a arms on the cross member. I also checked the numbers on the bars. On the right one it has stamped on it 317. On the left one it has a L and 217 on it. I have one nos bar for the right side it is stamped 522 R can I use 1new bar and 1 old bar on this car.

Reply from Bill:

Looks like your right bar is a left. The right bar should be an even number. Bars can be installed either end front/back, but there is a right and a left.

The three digits are the last three numbers of the part number, Cannot locate a bar ending in 317 or 217.

However, the standard bars should be 510 (R) and 511 (L) while the heavy-duty bars should be 516 (R) and 517 (L)

A bar stamped 522 will not fit an Imperial - it is for a Dodge Polara or Monaco.

Question from Bob (1968):

I need to ask a question about the torsion bars. On my '68 Imperial the right one is straight and the left one has a bow in it. Should I take it out and put in a another one.

Replies:

From Dick:

Definitely, if you can see a bend in the torsion bar, it is damaged. Replace it as soon as you can find another one.

From Carmine:

Now that is truly an odd situation. T-bars can break (unwind), but I've never heard of one bending.

The only explanation I can come up with, is that someone jacked-up the front end of the car using the torsion bar????

I guess I would also have to ask; how far is it bent, and in which direction????

No matter what the answer to these questions is, you certainly SHOULD replace the left T-bar. If it's bent enough for you to notice it by eye, it's just waiting to break.

A torsion bar is basically a spring that has been pulled straight, and when they snap, it's in a "spiral" pattern. While I've never personally had one snap (it's not that common, but supposedly quite memorable) the metallurgy is said to be rather delicate; in other words:

Do not hammer them Do not heat them Do not use "vice-grips" on them Do not taunt Happy-Fun Ball (R) [SNL reference]

If the left T-bar breaks, the car will basically collapse onto the suspension stops. At the least you'll end up stranded.

Make sure your replacement doesn't have any nicks or gouges... And you must replace a left torsion bar with a left torsion bar.

From Brian:

Torsion bars can be bent by dukes of hazard type driving (I did it on one of my dusters). Replace it before it breaks.

Question from Bob (1968):

I went over to garage today and removed the adjusting bolts on the t-bars. On the left side I have an half inch between the adjusting bolt and the pad that it rest on to raze the car. On the right side I have about three quarter of an inch. Could this be my problem with bottoming out. I was wondering if I need to remove the bars and move the pads to the bolt adjusters.

Replies:

From Demetrios:

Bob, I am not fully follow you. Did you remove the bolts completely from the lower control arms? If yes, are you supporting the car with lack stands? Or does the half and 3/4 of an inch refers to how much the bolt head sticks out from the control arm at the current adjustment?

I was wondering if I need to remove the bars and move the pads to the bolt adjusters.

I cannot follow this. What do you mean pads? What you may have to do is remove the T-bars from the anchor points at the rear cross member, and move them one full flat to wind them more if the car rides too low. I do not remember the procedure to do this and what needs to come off, but it will be well laid out in the FSM. 

From Paul:

So it sounds like the torsion bars were not switched prior to the last installation, right?

I have heard that one bar can be replaced. I may be wrong (again), but I thought the only thing that would make them require replacing would be a crack or some other evidence of a break. Otherwise, aren't they "bullet-proof"?

From Bill:

Looks like your right bar is a left. The right bar should be an even number. Bars can be installed either end front/back, but there is a right and a left.

The three digits are the last three numbers of the part number, Cannot locate a bar ending in 317 or 217.

However, the standard bars should be 510 (R) and 511 (L) while the heavy-duty bars should be 516 (R) and 517 (L)

Imperials, with their 3" longer front stub, are longer yet. Imperial bars are unique, prior to 1974, and do not interchange with any other car.

1974-78 C body bars are all the same length regardless of make.

The 512 and 513 bars were used on the fuselage Imperials, with 516 and 517 for H.D. use. So it will fit your 1968 Imperial. It may be a slightly heavier duty bar than the 1967-68 510/511 bars as the fuselage Imperials were heavier.

Just remember even numbers are right side and odd are left. With each pair, the right is the lower number - 510/511. 512/513. 516/517. 511 and 512 are not a pair, for example, but 512 and 513 are.

Question from Chad (1971):

The front end of my Imperial seems to sit a little low. I would like to adjust the torsion bars but have been warned by some that as they get old they fatigue and can break easier. I do not know if they have been replaced in the past or if they are original. Has anyone here had much experience with adjusting them. Also, what would be a recommended adjusting procedure?

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From Matt:

Yes, torsion bars sometimes break, but rarely. The biggest problem with their adjustment in my opinion is the adjuster bolts...these bolts have fine threads and can easily break ( again happened on my 74 during alignment- and they never told me! I found the damage myself while under the car later...It's still that way :( ) Ensure these bolts have clean threads and some lube prior to the procedure - other than that it's a fairly easy procedure.

From Bill:

Torsion bars can break, but it is rare and not worth any worry, so go ahead and adjust them to what you like, that is what I have done with no problems.

From Asa:

Torsion bars should be adjusted each and every time that the car is aligned.

From Bob:

In the first year of the "Torsion Aire Ride," 1956, there were many broken torsion bars, usually during the winter months. . This problem was caused by the interaction of the hexagonal end of the bar at its rear anchorage within the hex socket, when the two parts were brought together within the small tolerance of the fit. The problem was solved with the addition of a rubber boot type device, fitted onto the anchorage end of the bar prior to final assembly, it was packed with a grease-like substance that was just enough to maintain the necessary clearance. In those that broke, it became apparent that corrosion began within that unprotected socket - often over time, and in a climate where salt contributed to the corrosion. The fix worked and the problem was solved....

From Pete:

The RH torsion bar broke on my 66 Sport Fury while I was driving to work one day in 1982 or 83.

I was zipping along an undulating 2 lane rural road at about 45 mph when I crested a little rise in the road. As the suspension compressed on the other side of the rise, an awful CRRAAACCCKKK! sounded and the right side of the car dropped markedly. I drifted to a stop and took a look under the car. The bar had broken about 6-8" from the control arm end and it was an engineering textbook perfect torsional failure -- the end of each broken piece looked like a spiral staircase.

I drove the car home (feeling every ripple in the pavement), installed a spare bar, and made it to work by noon.

Question from Robin (1972):

Anybody out there know what the part numbers are for the torsion bar seals/boots and locks for a 1972 Imperial? I am trying to track these parts down but they are proving elusive and peoplpe are telling me they could possibly be found if I had a part number. Chrysler lists them as obsolete.

Replies:

From Elijah:

The seal is part # 2269 260 and the lock is 1639 171.

From William:

These seals are at the back of the bar and should NOT be in polyurethane. They are an oil seal anyway. From what I understand, the grease that's put in back there at the factory (and should be maintained if the bar is removed/reinstalled) is there for a reason. I recall reading an article about a '57 Fury that unexpectedly went out of control driving down the freeway. When the investigators started looking for problems, they discovered a broken torsion bar that was broken at the rear of the bar, not in the middle as most seem to do. Looking farther, they discovered that there was no assembly grease where the bar indexed with the rear anchor. The lack of grease had let moisture attack the bar and it was basically crystalized back there. I read that in a car magazine back in the 1970s, but don't recall just which one (possibly Motor Trend). When the bar snaps, it lets that side of the car suddenly drop to the suspension syst! em's bumpers, which can cause a situation where the driver is startled and can loose control of the vehicle.

As for interchangeability, most of the torsion bars are in the 1" diameter range, whether for a C-body, Imperial, or other similar Chrysler product. About mid-way from the front of the bar is a stepped area (where the special tool for removing torsion bars is clamped onto the bar) and it's highly possible that all of the bars are the same diameter rearward of that area. Those seals should be available in the aftermarket through NAPA or similar--of course, you'll have to find someone that knows what a torsion bar is first. They might also be available through Chrysler too.

Question from Jim (1973):

I pulled the torsion bars out of the '73 I'm restoring this weekend and noticed something that puzzles me.

I know there is a left and a right bar, but which end of the bars goes to the front (control arm) and which one goes to the back (frame)? It think I've proved to myself that by reversing the bar end-for-end it would end up twisting the opposite way, which would defeat the purpose of specific left/right bars.

I checked the '73 FSM, but can't find any reference to putting a particular end of the bar in a particular location. It also says that R or L is marked on ONE end of the bars, but in my case, they are marked on BOTH ends.

My bars are stamped as follows:

Right bar - one end says "UPD513L" the other end says "513L 1.02" Left bar - one end says "UPD512R" the other end says "512R 1.02"

I noticed on the OIC site a reference to torsion bars (not sure what year was being discussed) with the end marked left or right going in to the control arm, but since both ends are marked L or R in this case, that doesn't help.

BTW, I can't rely on how they were installed before I removed them, because I had them out myself about 20 years ago before I put the car away for storage, and may have got them back in wrong. Just for interest however, one was installed with the "UPD" end in the control arm and the other had the "UPD" end in the frame. (I suspect I had them in wrong!)

I am wondering if I am missing something obvious by not knowing what "UPD" stands for?

Does anyone know which end goes into the control arm, and if so, what is the source of this information?

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From Kenyon:

Somebody else fill in the blank, but Lowell Howe said that even numbered parts were for one side (drivers or pass.) and odd numbered parts go on the other for all Imperial (maybe Chryco) parts. I bet that there are other parts on your car that would allow you to deduce the answer to the above contention.

From John:

Even number parts go on the right side & odd on the left

From Brad:

"I've proved to myself that by reversing the bar end-for-end it would end up twisting the opposite way"

Think again. The t-bar would twist the same way regardless which end was mounted in the front or rear...not to say that it doesn't matter which end is mounted front or rear but the twisting direction would not be the reason as the twist would be the same direction either way.

1977 FSM makes no mention of any directional consideration when installing longitudinal torsion bars.

Question from Al (1982):

I am in need of the right front torsion bars for my '82 Imperial. Can anyone help?

Reply from Bill:

To help you out, all Mopar products with the transverse torsion bars used the same bars. There were two types - police and non-police.

Thus any F-body (Aspen, Volare), M-body (Diplomat, LeBaron, Fifth Avenue, Gran Fury, Caravelle), J-body (Mirada, Cordoba) or Y-body (Imperial) from any year will work. Just need the correct side.

Question from Jim:

I've loosened the tensioning bolts, removed the rear retaining clip, and removed the front bolt and I still cannot budge my torsion bar. Any suggestions ??

Reply from Mike:

It sounds like you're there; the torsion bar is just stuck due to the combined effects of age, petrified grease/crud and possibly rust. What you need to do is tap the torsion bar back out of its hex socket using a homemade tool (the Factory Service Manual will refer to a special tool for this purpose, but you can make one out of wood). You need to make something that can be clamped around the torsion bar, which you will then hit with a hammer to drift the bar out. It's important that you don't use vise-grips or anything like that on the bar that can cause the torsion bar to be nicked, or else your torsion bar can fail on you down the road.

I made a crude tool out of hardwood by drilling a hole the diameter of my torsion bars (approx. 1") through a 2" x 2" x 5" piece of wood, cross-drilling some clamping bolt holes (say, 3/8") perpendicular to it, one or maybe 2 on either side of the main hole, and then sawing the wood in half through the center of the main hole. A couple of bolts and nuts were then used to clamp the wood back together, around the torsion bar. Then I smacked the wooden tool a couple times and my bars were free.

Question from Zeke: 

The front of my car sits a little to the left. I have a few questions  1. Should the torsion bars ever need replacement? Not routinely, but some do go bad 2. Does anyone make these torsion bars anymore? MP and the aftermarket have replacement/upgrade bars for A, B, and E  bodies, but I don't know about our big beautiful Imperials.  3. Does the average mechanic know what they are doing with torsion bars?   

Replies:

From Bill:

Actually, the whole idea is pretty simple, but someone who got started in the profession recently may never have heard of them. I would try adjusting your bar first, I like to try four turns of the adjusting bolt at a time, recheck for stance.

From George:

As it's been discussed recently, and I learned something today.... As I recall the discussion has been 'what are they' and 'do they wear out'. In a nut shell they are the front 'springs', and like any suspension component they do wear out. More specifically they are tempered steel bars w/ hexagonal ends that fit into the lower control arms and a cross brace between the frame rails. Spring rate is based on a calculation that includes length, diameter, and some constant. I have the formula somewhere. It should include a fractional multiplier for mileage, but doesn't. In order for the lower control arm to pivot on it's shaft, it must twist the torsion bar, thus providing the spring action, with little or no 'bounce'. A stiffer 'spring' is obtained by either lengthening the bar, or increasing it's diameter, or both. Imperials being the heaviest cars made by Chrysler, naturally have the longest bars. Trying to put a longer-than-designed-for torsion bar in your car is generally considered to be unwise as it involves relocating the rear cross-member. Heavy-duty set-ups use a larger diameter bar, but that may be a tough find at the parts counter or in the aftermarket. As for the wear issue, twist something enough times and it will weaken. I work in the mystical land of big business, and believe me, it happens. In the case of torsion bars, mileage isn't the only contributing factor. Driving habits, terrain, load, and the state of the rest of the suspension all must be considered. Bumpy roads and blown shocks will make the torsion bar work harder. I suspect there is a reliable way to measure the actual spring rate of the torsion bars in your car to determine if they are worn-out, but I sure don't know what it is. If you've already done the h-d gas shocks and the nose still bounces badly, change the bars. Which brings me back to today's discovery. While tearing out the rotted k-frame in my never-hit, never garaged (until last month), 275000 mile, 75 Cordoba, I happened to roll one of the torsion bars across the garage floor. It is so worn out that it actually has a bow in it. In fact both the old bars have bows in them. This of course prompted me to look at the new torsion bars--they are straight as an arrow. Guess that explains why I've been going through those lifetime warranty Midas shocks so frequently. The other lesson I learned today is that you don't need a torsion bar removal tool to remove a torsion bar, as long your taking the lower control arm out.

From Mike:

Even when torsion-bar Mopars were current, there was a great deal of ignorance about them. I used to hear front-end guys go on & on about how hard it supposedly was to align one right after high miles. My uncle (a California Highway Patrol officer @ the time) was nice enough to introduce me to a couple of the CHP mechanics, who explained that all the alignment one might do was worthless if one did not also make sure the torsion-bar height was correctly set. They also showed me that height adjustment was not that tough to accomplish. (Guess those Brand X guys were put off by something, well, *different*...) If the torsion-bar height is not correct, the geometry will be thrown off in the rest of the front end, which caused the aforementioned sniping.

From Frank:

When I changed this bar, I did not remove the lower control arm. Did only: Jack up the car and set stands. Unwind tension bolt (height adjustment.) Remove spring retaining clip lock ring from rear of cross member Side the bar rearward and remove I did not need to use the tool (C-3728) described in the shop manual (page 2-8) the bar was loose enough to remove by hand. Note that the above procedure is recommended by the factory service manual. 

Question from Lawrence:

Has anyone had a torsion bar let go on an Imperial? 

Reply from Ken:

I had one break on a 57 two-door. I was pulling into a driveway and heard a very loud pop and the right front dropped. Pretty scary, but no significant damage done. The car had less than 100K and was not rusted.

Question from Tony:

I have just reassembled the front end of my car, having completely cleaned and painted the engine bay and replaced all the bushes and ball joints.. Everything looks fine except the torsion bars. I don't seem to be able to get any tension even after tightening the adjusting bolts as far as I can. When I let the car off the jack it looks like a low-rider, and that is without the engine installed. The problem is, I have a '60 FSM and it looks to me like the '61 has re-designed anchors which makes a nonsense of the FSM instructions. Can anyone tell me how to set up the torsion bars correctly? I also made the mistake of relying on my memory as to which torsion bar fitted which side of the car. I have fitted the left T/bar to the driver side and the right to the passenger side. Was I right? Finally, can the bars be removed without disassembling the control arms? I would hate to have to go through that process again.

Reply from Phillipe:

I've had the same problem with mine ! When I tightened the bar bolt i stopped after a while 'cause it was hard to turn. I lowered the jack and .. the car looked like yours: a low rider. As the jack was at the front under the front cross-member, the jack handle was jammed by the bumper and I need to find another jack to remove the first ! So I put an extension (3 feet of tubing..) on the wrench and i tightened and tightened and tightened... Then I lower the car: better. Then still tightened and ... In the FSM they say that the first setting is about 1 inch of threads above the swivel but now, my car has a correct height with 1 1/2 inch of threads above... Note that each bar has a R or L stamped in one end: this end goes to the control arm. On the other end (to the rear of the car) there's a number (962 right or 963 left on mine). Torsion bars are same from 57 to 66 so you would have the same number or 960/961 (lighter) or 964/965 or 966/967 (heavy duty).  

Question from Chris:

At lunchtime today, I went to get the car and immediately noticed how much lower the front end is. And so here I am... The mechanic has yet to look at it again, but he insists the right torsion bar was adjusted as far up as it can go, and also said he raised the left one to match. (But I am sure the car sat perfectly level before.) Any thoughts on what could have caused this change? The new shocks? Something when they dropped the lower control arms? I'm at a loss myself... I cannot make sense of anything that would have made the car suddenly sink a full inch.

Replies:

From Pete:

What has probably happened here is as follows: The torsion bars were unloaded so the lower control arms could be removed. No problem. Then, when the control arms were reinstalled and the torsion bars inserted, the mechanic didn't index the bar hex to the adjuster hex properly -- he's probably one "flat" off. Therefore, he's probably correct in saying that he's run the adjuster bolts to their stops. It's just that his starting point was off. The bars should be unloaded and backed out out of the control arm sockets. Then loosen the control arm pivot bolt and twist the hex socket until the adjuster bowl is against the adjuster bolt rounded end. Reinsert the bars, crank down the adjusters and -- voila! -- you'll be riding high again. PS: there wasn't anything wrong with the first rebuilt steering box. all the mechanic had to do was center the spool valve by loosening the two bolts on top and tapping the housing front or back a bit. PSS: unless the upper control arms or tie rod ends were replaced, you shouldn't have needed a front end alignment. something is a little weird here.

From Steve:

The only thing I could think of is that maybe the guy didn't install the "hex-end" of the torsion bar into the control-arm the same way it was before. Now he had to adjust it up all-the-way to get it close to the original height. Just a guess. The shocks wouldn't do it unless you have coil-over shock...and I will most likely bet that those KYB's (that I might put on my Imp) are not that style. I'm not an alignment expert, but I think the car has to sit at the correct height in order for the alignment to be right. So that would mean that is "off" too. I hope this info helped.

Question from Mike:

It was recommended to me that redoing the front end without having the  torsion bars re-tempered was a mistake. Has anyone in the club had torsion bars re-tempered? What was the difference in ride & handling  (that might be attributed to this)?

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From John:

I was all worried about this same thing when I had front end work done on my '65. My mechanic said not to worry. He set the ride height (after which you must redo the alignment). He used to do demo derbies with Imperials (back when) and said they always cranked the torsion bars up as tight as they would go, I guess to bring the nose up to make the cars more lethal. Anyway, he said he never (or almost never) broke any torsion bars even under this extreme use. Evidently they have plenty of adjustment built into them. That's about all I know, except a couple of calls to spring shops found none who could or would re-temper them.

From Nancy:

I have never heard of this. Seems to me that re-tempering would involve heating a torsion bar which would ruin its spring capabilities I think. Most torsions bars outlast the cars they are on. Unless the car has a huge amount of mileage on it they usually still have plenty of adjustment on them. When you align a car with torsion bars you should set the ride height to the factory spec by adjusting the torsion bars. I've always found that MOPARS handled real well when the bars were down.

From Wayne:

I have never heard of re-tempering the torsion bars before. I had the front end rebuilt on my '66. I am satisfied with the results, and I didn't have the torsion bars re-tempered.

From Gene:

I agree with Nancy. If the torsion bars have held the suspension at the proper height over the years they will probably keep on doing it. The bar has been through probably millions of flexes in its lifetime and is still viable. If you redo your front end, just readjust the bars to provide the proper height and you shouldn't have any problem. My 65 vert. with over 120K miles and after sitting 20 years had no problem after installing new front end suspension. If one was to attempt to temper a torsion bar, I would hope that that person is an expert Heat treat specialist. Tempering is a lot more complicated than just heating. The degree of heat, the rate of heating, the rate of cooling, the atmosphere of heating, the means of cooling are all critical if one is to maintain the proper crystalline structure of the steel. Again, I would say don't re-temper.

Question:

How do you adjust the torsion bars?

Reply from Norm:

This is a somewhat sensitive procedure in that you must first jack up the front end and take the weight off of the wheels before making any adjustment. But before you do that , you must measure the ride height distance properly-its explained in the FSM for any year in which torsion bars were used. Then, I would make adjustments one full turn at a time-someone suggested 4 turns- that is a very big adjustment if the ride height is anywhere near close and you will over shoot for sure . Then lower the car, bounce it a few times and re check the ride height . It's a tedious job but it is the best way to get the proper result. You will know if your torsion bars need replacement if you run out of turns (there is an up-stop created by the bolt's contact with a cover bracket) before you get to the right ride height. Or, if you adjust the front end properly only to have to do it again in a day or so, your bars are shot. In either case, its time for new bars-or more likely new used ones from Murray or Bob. CAUTION: WHEN INSTALLING REPLACEMENT BARS MAKE SURE THE PERSON YOU BUY THEM FROM MARKS NOT ONLY LEFT AND RIGHT, BUT WHICH WAY FRONT TO BACK THEY WERE ORIGINALLY INSTALLED IN THE CAR FROM WHICH THEY CAME. THE BARS ARE NOT INTERCHANGEABLE SIDE TO SIDE OR (ONCE THEY HAVE BEEN USED) FRONT TO BACK. 

Question from Dave:

I would love to have new torsion bars for my Imperial! And I do have a set left over from my 1971 Imperial that I could measure. It has been my experience that at about 130,000 miles, the bars lose that "new car ride" despite adjustment.  Are torsion bars interchangeable?

Replies:

From Norm:

For what its worth, I've done a bit of research on torsion bars and the most oft repeated warning I've noticed is that they are not interchangeable side to side. I guess it's because they flex one way on each side and are not metallurgical adaptable to flexing the opposite way if improperly placed. The bars are marked with an "L" or "R" on the end that's visible when you pry the plastic seal off the rear of the anchor. It would be my guess that not only must you put them in on the correct side, but it would be mandatory to put them back with the marked end in the same place as well. I have a friend in the heat treating business who says he commonly re treats torsion bars.  My vote is to leave them alone if they yield correct ride height. 

From John:

No, all torsion bar must be made out of basically the same spring steel, so it's the length and diameter that matter. Which why all the other cars have shorter, thinner bars which you can buy all you want brand new.

History Discussion About Chrysler's Use of the Torsion Bar in Front Suspensions:

Doubtless there is someone who knows the TRUE reason (if there ever is such a thing concerned with automobiles; the entire exercise is highly irrational) for Chrysler switching to torsion bar front end suspension. I am willing to bet it has a lot more to do with being able to create the illusion of a car whose external dimensions are "closer to the ground" than anything a coil or leaf arrangement can produce. I'd be surprised to learn that anything but styling was driving the deal with engineering struggling to keep up. After all, the owner NEVER opens the hood, that's the job of the grease monkey at the local Gulf or Esso. In fact, as a sprung car with an independent front suspension must hang it's weight from at least one "end" of the spring to work; a torsion bar has the advantage of being able to do it from either of the control arms; and, as in Chryslers iteration, this is done from the lower control arm which has the aforementioned benefit of a much lower hoodline as a tower for a coil spring is unnecessary. The secondary (but still quite significant) benefits are that not only is the ride height adjustable, but more importantly that the weight of the vehicle is now on the lower versus the upper control arm. This makes for a much better "lever" than the standard coil arrangement. It is also possible, all other things being even, to make the car a better handling vehicle than it's competition: as the weight of the car body resists the motion of the suspension all on a lower plane (in road height) the amount of "correction" is lower than would be the case with a coil spring. Anti-dive, anti-squat and resistance to weight transfer in cornering also benefit. It was, and remains, well ahead of its time. As for "space benefits" drive any of a jillion MacPherson strut suspended cars HARD and know that this 1953 invention isn't good for much of anything. As Duricy points out, these are not porcelain china, but automobiles expected to get down the road a hell of a lot faster and with less work from the driver than the with the competition. Remember that great ad for the 300? South Texas to Acapulco in a day? The only real question is why Chrysler was too cheap to do the rear as well a la Packard. A car suspended at four points by torsion bars has some real superior attributes on paved surfaces.

Replies:

From Dwight:

"The main reason Chrysler began using torsion bars was to improve handling with no penalty in ride comfort... "...Though tried on some prewar European models, torsion bars weren't tried in America until the stillborn 1946 front-drive Kaiser, and the first such production suspension was Packard's four-wheel 'Torsion Level' setup introduced for 1955. "While a conventional leaf or coil spring tends to transmit road shocks directly into a car's structure, a torsion bar absorbs most of them by winding up against its anchor point with a twisting motion. This and greater compactness are the torsion bar's two main advantages. (Indeed, the bar can be thought of as nothing more than a tightly wound coil spring that has been stretched out into a long, thin rod.) To these, Packard's system added a special touch: the bars linked front and rear wheels longitudinally as reaction points for each other (one bar per side). Torsion Level also had an electric load-leveler to compensate for the weight of passengers or cargo. Unfortunately, it was a complicated device consisting of no fewer than seven electrical switches, solenoids, and a control box, and it was susceptible to dampness and corrosion. "Chrysler had originally intended to switch to front torsion bars for 1955 or '56, but held off. One Mopar stylist noted that Packard might have claimed 'that their system was twice as good!' Torsion Level was literally that, since it affected both front and rear wheels, but it was also trouble-prone and really didn't do all that much for handling. By contrast, Chrysler's much simpler front-only Torsion-Aire made its 1957 cars the best handlers in America, aided by more conventional improvements such as a wide lateral spring base, a lower center of gravity, higher spring rates, a higher front roll center and improved rear-steer. Torsion-Aire Ride sent GM and Ford scurrying back to their drawing boards, where they produced notorious air suspensions that didn't work half as well and were quickly canned." So, that's the torsion bar story for Chrysler in a few paragraphs...

From Dick:

The Packard system was developed by an inventor named Allison in the early 50's. He built a running prototype chassis with only a skeletal body to show off the advantages of his design (much lower resonant frequency [read luxury car ride], zero dive [braking] and squat [acceleration], plus ease of adding automatic leveling and operator [manual] control, plus the main advantage: interconnection the front and rear suspension in such a way that the jolt of impact from a road irregularity was cut by half. He took this prototype to all the major manufacturers trying to sell his design and patent rights, but no one would bite. Finally Packard paid the royalty for the design, but Bob Allison retained the patent rights, and continued trying to sell his idea for many years to any one he could think of. While the original patents expired in the late 60's, he kept making improvements and kept a tight hold on the rights that way [more patents]. As recently as the mid 90's, and perhaps to this day, his son is still sometimes seen tooling around in the prototype, and I'd bet they are still trying to sell the idea to someone. Like many really creative ideas, this one really works, as anyone who wishes can have demonstrated to them by me or any other 55-56 Packard owner, but was priced so high that others thought it was not worth it. Also, during 1955, Packard had some serious quality control problems, which resulted in the Allison system getting some undeserved bad press. My experience for over 20 years since my first one of these cars is that - once repaired and properly adjusted, the system is 100% bulletproof. I have never had a failure in any of my 17 "Torsion-level" cars. I have never heard of a broken bar, by the way. These cars have been sitting on these bars for 44 years now, and have not settled more than 1/2 inch.

From Tim:

I think the German panzer tanks had torsion bar suspensions that let  them run faster over rough terrain. I also think it was designed by an American but he didn't have any luck marketing his design and it somehow ended up on the panzers... maybe someone a little more worldly (older) than myself knows the rest of the story

From Clark:

Hi gang, Can't pass this one up. Tim is right about the German tanks having torsion bars and he is also right that they were "borrowed" from an American Genius by the name of Tom Christie (not certain of the spelling). He developed an armored vehicle chassis with torsion bars during the early 1930's that was really incredible. He asked for and was granted a public showing of this set of vehicles at Aberdeen Proving Ground and invited reps from all of the major European countries( UK, France, Germany, and Russia) plus reps from the US Army. At that time there was openness across the world of armaments makers. At this demo, the tanks chassis was so fast that it was said to be able to leap 10' wide ditches and run up to 100 mph( if you could build an engine that good). The Germans were miffed cause their engineers hadn't come up with it, the French didn't believe in tank warfare, the Brits and the US said that there was no need for a tank to go faster than an Infantry soldier could walk in the final assault, and the Russians bought every thing he had , loaded them up and took them home. This system of track became the track design of the infamous T-34 tank that stopped the mighty German Panzers. And by now just about every tank and armored vehicle in the world is running on some variation of the Christie suspension. There's much more to this story but I run out of space and time here.

From David:

The torsion bar has been around about as long as the spring. It was even used in some 15th century furniture. Wood torsion bars, of course. It is also common in many machine tool applications going back to the last century. It has been used in horse-drawn vehicles. From memory, I think it is used in the typical racing sulky. The application to automobiles is probably as discussed. The "anti-sway" bars used on both front and rear of many cars are quite old and are also torsion bars.

From Mark:

I don't know if they were first, but Citroen's Traction Avant came out in 1934 with torsion bars all around. They were able to reduce car height AND maintain the massive suspension travel required by French drivers to go fast over their poorly built/maintained roads. They were still making and using Traction Avants after WWII, a good thing because by then, the roads were even WORSE! (What with bombing, shelling, and half-tracks and tanks and tearing them up....) These cars wouldn't dive when braking; they would squat. Dips and bumps that would send other cars pitching fore and aft would make Citroens rise and fall evenly all around. They couldn't be broken. The system was so good that when it came time to replace the Traction Avant in 1955 (and up the suspension ante), Citroen had to ditch springs and shock absorbers altogether! The DS and ID had the infamous oleo-pneumatic suspension, still a Citroen hallmark. (And, incidentally, used by Daimler-Benz in the late '70s for their then flagship car, the 450SEL 6.9.) Torsion bars have applications outside of the suspension, of course. Chrysler used them for hood and trunk springs on various '60s and '70s passenger cars. Honda's CB450 (motorcycle) engine had torsion bar VALVE springs! And finally: Ever wonder about the L-shaped torsion bars used on the late '70s/'80's Chrysler rear-wheel drive cars? Story is that the Aspen/Volare' were originally designed for coil springs. As the cars neared the production stage, some Chrysler exec. caught wind of it, and demanded that torsion bars be incorporated in the cars' suspensions. The project was too far along for a total re-design, so the clever, budget-strapped chassis engineers came up the "bent" torsion bars.

From Mike:

Much as these bars have troubled me over the years, this is not the way I heard it... ...the story I remember was that Chrysler was trying for a ride more like that of the larger cars, which required a longer torsion bar, which could only be done sideways on the F-bodies and their descendants such as the '81-83 Imperial (mandatory Imperial content) for some reason. Also, Chrysler advertising was consistent in that era in pushing torsion bars as part of the corporation's superior engineering, and would not have been likely IMO to drop that on that particular platform. The L-body (Omni/Horizon) was a break from tradition in size, and the MacPherson struts that the rest of the small car field was using came as no real surprise there. I believe I read about this excuse for transverse torsion bars in the Motor Trend Car Of The Year issue in which the Aspen/Volare received that reward.

Question from Philippe:

I wonder what could happen if the torsion bars are tightened more than factory setting, i.e to compensate too low front height (smaller tires than original). Is there a possibility of breakage? Lack of drivability (and comfort)? 

I ask this question because my car has radial WWW tires (225-75 x 14) and they have 2" less height than original bias 9.50 x 14. So the car is 1" lower than original and I suffered from some problems when I run over speed bumps. When the front wheels go down this damned speed bumps the rear wheels haven't began to climb the beginning so the middle of the car (exhausts..) scrapes the cement. I don't have the problem with the '58 Bui*k, it is higher than the Imperial. I know also that all the fellows who have Corv*"te, Trans'*m, Cama"%o etc have still more problems than me.  Does anyone have any suggestions?

Replies:

From Chris:

If your ride height in front is too low, your torsion bars need to be adjusted. (New shocks will not affect ride height.) Although the shop manual gives a very detailed procedure, I usually match my front height to the rear height by parking the car on a perfectly level surface and taking measurements at the ends of the frame nearest the F&R wheels. Then I adjust the front torsion bars accordingly. Of course, when you adjust the front bars and new front end alignment is necessary.

Also, by all means get the proper 9:50 x 14 tires. They would give you almost 2" of additional ground and the car would ride like it was designed to do.

From Dick:

I doubt it would add much additional stress to your torsion bars to take them up a little more - as the weight of the car is not changed, thus the total torsion on the bar is only slightly increased by asking it to hold the car a little higher. On the Packard, which uses torsion bars also, it is common to adjust the height of the car every time the load in the car is changed, and it can also be changed with an adjustment to the front end, and I've not heard of a bar breaking yet.

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