IRS torsion bars and spring plates

[Peterhubble]

Can anyone help . I am restoring a 1978 1303 cab,before I dismantled the spring plates and torsion bars I noticed that the protruding end did not sit centrally to the cover plate! I assumed it was because the rubber bushes were worn.On reassembly with new rubber bushes the reartorsion bars still sit off centre to the cover,so I have a gap at the bottom and virtually no gap at the top.HELP

[busman78]

Loaded tension on the torsion or not?

Did you first crank the tops down all the way tighten the bottoms? Loosen the tops, bring the bottoms in some, see if that helps.

[Peterhubble]

[busman78]

Picture(s) if possible, please

[modok]

Did you install the new bushings with the thick end up?
There is a right and left.

[bobinphx]

My experience is that the rubber bushing (sometimes called grommets) are not of the correct durometer rating, thus they are deforming do to the tension and to some extent geometry of the torsion bar, spring plate and the standard installation process.

What happens is that the inner bushing has tremendous pressure on it as the spring plate is moved from the resting position to a position that allows the spring plate to move inward past the bottom spring plate stop. This motion puts a lot of pressure on the top of the bushing and the bushing compresses more than the original bushing did. bottom line the inter bushing is collapsing at the top.

Once the spring plate and cover are in place, this collapse puts the spring plate into a negative camber situation, which then brings the rear trailing arm in to a negative camber situation as well (really noticeable with the dual spring plate cars as the duals do not twist to compensate AT ALL)

The only solution I have found is to use a higher durometer rated bushing (ie. harder). There are a few options.
1. Urethane (note that these also vary in durometer readings)
2. Delrin (injection molded seem to be a good choice )
3. Bronze. (expensive, but look really solid. I would be concerned about wear on a daily driver)


I had the same issue of the spring plate torsion end housing not being centered in the bolt on cap. I changed to the Yellow injection molded Delrin, with a LOT of anti seize compound as lubricant and I love them. By having the end of the torsion bar centered in the housing, a large amount of my negative camber went away. So far no noise either.

All of this is just my experience and opinion. your results may be different.

[vamram]

[modok]

They made 20 million of the things, all over the world.
If you can't get this rubber bushing thing right.....c'mon, whos fault do you think it is?

You have to look at what is different about your bushings or your car, because the other million out there are not really having a problem.

[bobinphx]

urethane are made by empi and others...

saco makes injection molded Delrin. (yellow)

I think atomwerk makes the bronze?

and yes, there are 20 million rear torsion vw's out there. There are also 20 million crummy parts out there as well. I only know what worked for me with no defection at the spring plate / torsion bar.

[74 Thing]

Saco makes the yellow ones

http://www.pacificcustoms.com/saco94-3022.html

[Peterhubble]

Thanks all for input.
I will post pics!!
I have assembled loads of type 1 rear suspension set ups over the years,with no problem.
Going to try harder bushes,( I just have new stock ones at the mo)
I also have a pair of rear torsion bars and spring plates from a scrapper that I am going to try!

[modok]

Good.
Hey, delrin could work ok, that's neat that those are available but I just would not be so quick to jump ship. Almost every vehicle on the road uses rubber bushings, nothing better has yet been found.

Maybe the bushings are not made right, or covers are wrong. I bought some empi covers once but found they were shallower and larger diameter where the rubber goes.....so I didn't even try them, right into the scrap bin. If you find the rubber bushings are just a bit loose, try putting a shim behind them to tighten them up. Squeeze them sideways a bit more it will tighten them up in the other dimensions as well.

[RailBoy]

Hey Modok, this is an interesting topic on how much you can tighten up the rear of the car. Do to "Squish" during operation plus "Expansion" of the Bushings under driving condictions, which to me are street, what do you think of the Bushings covered if you make a scale about there inherent differnt qualities? Have to tackle mine soon and this is great info, mean, Bronze??? RB
_________________
[quote="smitty24"]"HELP, I ported my own heads and now have fire coming out my ass" .[/quote]

[slalombuggy]

Are you looking at the bushing with the car resting on it's wheel or sitting on jack stands? Look at the position of the spring plate in the bushing with the wheels sitting on the ground and see if it has moved.

I think what is happening is that with the car sitting on jackstands the spring plate is under load and pushing down on the stop which forces the torsion bar end up into the top of the bushing and cover plate. Once it is sitting on it's wheels the pressure is taken off the bottom stop and with the pressure point moved further back now pushes the spring plate down into the bottom of the bushing.

BTW, VW torsion bars don't bend.

brad

[Bruce]