More rear torsion bar problems

[janz]

Ok after third try of reindexing the torsion bar on the drivers rear, raising it up each time, my calc. should have brought it up by 1.25 inches on the final try. After each try I put everything back together and the ride height looks good and my corner balance is now pretty close. Drive for 10-20 miles and then look at it and the drivers rear is sagged back down where its only a fingers width from the top of the tire to the fender lip. Torsion bar not broken. I beleive its old (origonal equip on 86 carrera) and I don't think it has its origonal spring left in it. Now I read some can wear that way and others say no it either stays Ok or breaks, whats the real story. Then starting to wonder if the female splines mounted in the tube or the radius plate cap are not solid (fixed) anymore. Before spending money on new torsion bars I need to know if where they slide into isn't the problem. Don't want to pay for another alignment or really drive the car before this problem is resolved. I can't beleive reindexing the bar to get greater ride height each time then having it sag back to where it all started from the beginning is right. If someone can reasure me the female splines are fixed and won't move then I'll buy the new torsion bars, replace both sides on the rear even though its the drivers side giving the problem. Also should I go with OEM or are the aftermarket as good or better (I know they are less expensive). Help me out here guys, the manuals aren't doing anything for me at this point.
Signed, Tired and frustrated (again)

[JP911]

I'm not sure what your exact methods are, but the suspension needs to settle after the car is put back on the ground. I usually just roll the car back and forth, and sit/bounce on the bumper. If you're not settling the car before taking your ride height measurements, then this is part of your problem. I wish I could help with your question about torsion bars wearing out, but I'm not sure. Have you been using the ride height calculator that is available on the web? It's on this web site: http://www.vintagebus.com/. You input the weight of the car, torsion bar diameter, and desired ride height and it provides the spring plate angle.

[John Brandt]

Are you entirely sure that the spring plates are not adjusting themselves? You've got to get them really tight or they'll settle

[burgermeister]

+1 on letting the car settle.

When I did this, I swapped my spring plates left-to-right to get the fat part of the rubber on top and the skinny part on the bottom (rubber bushings were quite eccentric).

The car settled quite a bit afterwards over a 1 week period. I adjusted the spring plates once by 15mm, then again by 10mm. I even took the LH side apart again during the 2nd adjustment as I was worried I had swapped the LH / RH side torsions bars and was about to break one. I hadn't - just settling of the rubber bits.

I did break a torsion bar in my bug once. It was in no way noticeable before the break.

[janz]

How can you increase height on the torsion bar by an 1.25 inches and then have it settle back to where you started? It almost seems to me that either one of the splines is bad (stripped) or the female end that they insert into is bad, possibly slipping? I don't know how they (female socket ) that the bar goes into are made. Are they welded in place or are they molded into a rubber sleeve, if they are in the rubber sleeve is it possible that the rubber is torn and allowing it to slip that far until the heavy load is releived. I never got the cap fully off to look at the splines as I was able to turn the bar to reindex on inside then turn the cap on outside to reindex. It was pretty hard getting the bar into the inside so there wasn't enough room to remove the cap completely but enough room to turn the bar to reindex. Something is moving and not holding where its been set and yes everything is tight enough as I marked the plates and bolts (adjustments) to return them to their origonal posistion and they are still there but that side sagged down again, there is no way it can settle that far without there being something wrong. Need to know what the inside of the cap that holds the spline looks like and the inside of the tube taht holds the inside spline looks like or how its built. I don't mind buying new parts as long as I know its the part I need to fix the problem.

[janz]

BTW I was using the angle finder each time and each time increased height for a total of 4.5 degrees, Three times I did this and took the car for a ride and it "settled back to the spot I origonally started from. Take 2 steps forward and the car "settles as you call it" 2 steps back. Went from 29.5 degrees to 34 degrees. Something is definitely wrong. Read every post and Bentleys and 101 but they don't cover this problem .

[burgermeister]

You have to also take into account the angle of the chassis when you measure the spring plate. You probably did that though. Does sound a bit odd. I can't imagine the splines slipping. the female parts are formed directly in the metal - no way for that to come loose. I don't think your torsion bars are at fault - they don't plastically deform much. They just crack & break. Unless your bars for some reason are lacking in the yield strength dept.

I took mine out at 32 deg, put them in at 32 deg, and indexed them up 2 or 3 further degrees with the spring plate eccentric adjusters ...

The alignment (camber / toe) bolts also can & will affect ride height. Sounds like they're tight, but it never hurts to double check.

I'd pull the bar and have a look at it, if only for piece of mind (err, peace of mind. My name isn't Eddie)

[janz]

When you say the sockets that the splines fit into are formed in the tube and the spring plate do you mean they are all metal (machined in or welded) or is there hard rubber around them attaching them to the tube and the spring plate (cap end). Trying to figure out wether I need new bar or springplate. Everything else is OK. If I only knew the manufacturing process of putting the sockets in each end that accepts the bar splines it may help to determine the problem. I don't want to buy new bars only to find out the sockets in one end or the other are slipping. I could add 10 degrees to the spring plate and then jack it into position to install all the bolts and have a 4" space between the top of the tire and the fender lip then drive for 10 miles only to find out it sagged down to where I can just barely fit my finger between the top of the tire and the fender lip. At htis point I don't think its the bar itself I think either the socket in the spring plate is slipping or the socket in the end of the tube is slipping allowing the spring plate to go back to the origonal position until the sway bar actually stops it from slipping any further. Hasn't anyone ever taken one of these apart to see how they are made?

[JP911]

Perplexing problem. I've seen pics on this board of cars with broken torsion bars and the wheel was stuffed all the way up into the wheel well. Before buying new torsion bars, I would remove the bar completely and get a closer look inside the torsion bar tube with a flashlight. FWIW, the settling that takes place when you put the car back on the ground is all in the shocks, and not the torsion bars.

Here are a few other ideas on what might be going on:
1. inner torsion bar splines rusted and crumbling
2. spring plate bushings are deformed to the point of being flat
3. the ride height adjusters on the spring plate are loose
4. the splines in the spring plate are rusted

[Alan L]

Originally Posted by janz

After each try I put everything back together and the ride height looks good and my corner balance is now pretty close. Drive for 10-20 miles and then look at it and the drivers rear is sagged back down where its only a fingers width from the top of the tire to the fender lip.

Your ride height needs to look better than 'good'. It should be sitting TOO HIGH - about an inch or two too high just after reindexing. It takes some time to get it to settle.
Are you sure you have got the adjustment right. You can try marking the index points with felt tip pen or something - to check yourself against. While since I did this - but you can mark original vs finished marks. Are you foward indexing one lot of spline vs rear indexing the other - ie inner vs outer? It is possible to get lost during this. Disturbing the suspension then putting back in original position would leave you about 1-2 inches high initially - until it settles out.
Regards
Alan

[janz]

Kept careful notes on every adjustment. Before initial adjustment angle was at 29 degrees (yes lower bushing and bolt removed from cover cap) and turned inside spline 4 notches clockwise then turned spring plate 4 notches counterclockwise this gave me an angle of 31.5 degrees what I figured was to be .75 of an inch. Sagged after ride. Yes i moved (stood) on rear bumper and front bumper a few times to settle it in. Reindexed the inside 2 more notches (clicks felt as I turned bar against the spline / socket interface) clockwise and the outside 2 more notches counterclockwise. checked spring plate angle at 33 degrees. took for ride sagged back to origonal. Moved both 2 more notches and took for ride and sagged back to origonal, now tell me I should keep doing this? This is where I stopped and said somethings really wrong as I should be at US ride height by now but can only get finger between tire and fender. Keep in mind before ride and after reindex I have about 3 inches between the top of tire and the fender lip. Get back from ride and only have less than an inch of clearance there. Next step as suggested is to remove the torsion bar completelyand check the splines and sockets visually. Can't figure a way to load 800 lbs on the bar to test/ see what happens.

[JP911]

Before you pull anything apart, go check to see if the top of the spring plate is resting on one of the four bolts that holds the plate in place (the one in the upper right corner if you're facing the car). Peek in there with a flashlight. The reason I suggest this is that I can't imagine the the torsion bar is only partially failing; something has to be supporting the rear of the car in order for it to be continuously settling to the same place regardless of changes in the spring plate angle. I've found that these cars are very sensitive to even a single degree difference in spring plate position.

[burgermeister]

When you take the spring plate off the arm to re-index, did it's free angle change? In other words, you set the free angle at 33 degrees and now when you take it apart it's at 29 degrees? If that's the case and it isn't the spring plate ride height adjustment, it might be the splines. But if the free angle stays constant, the splines would appear to not be slipping.

[janz]

When first starting I set angle to 32 and when it dropped I took apart and angle changed to 30 (free angle as you call it). When I get home from work today I'll pull the rocker trim and plug off and take it apart again but this time completely remove it from the car to get a good look at the bar splines and sleeve splines. They must be slipping somehow.

[burgermeister]

Wacky stuff. 1 spline is about 8 degrees or so, so it can't be splines slipping. The splines in the spring plate are part of the torsion bar cover. In the car, I don't know what evil lies at the end of the tube. I would imagine a welded in piece of smaller steel tubing with splines in it...

I am curious what you will find - may it be inexpensive.

[janz]

The spline sleeve in the spring plate cap is that welded or rubber filled? I think either the splines on the bar are worn off or the sleeve if it has rubber around it let go. Its still got enough to hold some weight but not the full force of driving and hitting bumps. At some point the sway bar and gas shocks help to decrease the load as it sinks so it stops at that sagged point. I am interested to find out what is wrong also, I keep thinking new tube to cut off and weld to under body or new spring plates and set of bars, all over 1K easy.

[mikeatfhc]

I don't know where your problem may lie - but I have my car tore apart right now for a new suspension... here's a photo taken looking 'down the rabbit hole' -or- into the torsion bar tube of an SC.

This might help you visualize the female splines inside the torsion bar tube.

[janz]

Looks as if its an assembly pressed down into the tube. Would you have a pic of the sleeve in the cap at the spring plate, thats where I think my problem may be.

[mikeatfhc]

Sure - this is after I cleaned it up using acid - it was rusted like you wouldn't believe. In fact when I pulled my torsion bars and spring plates the torsion bars were rusted to the outer caps - it was a bear getting them off.

Here ya go...

[janz]

Thank you very much, I wonder if they're different than the 86 with adjustable spring plate. Looks to me these sleeved splines are all integral metal to metal no formed rubber like on a shock absorber. Just got the car jacked up again so ready to take it apart again. Let you know what I find.