Pete L

I am doing new shocks and replacing upper A Arm bushings with a kit purchased from Rodger. The car is early 86 with smaller diameter bushings compared to 86.5 forward. I have the old bushings out and the new pressed into place on one side. Here are my questions (photos attached to illustrate):

1. There was no steel crush liner in the original A arm or on old bushings (photo 1 and 2). Did I somehow miss steel liner, I sure can't see them? I cleaned the hole and lightly saned with sandpaper and sure seemed like it was aluminum shavings.

2. When I tighten the 19 mm axle bolts, the A arm becomes absolutely rigid, does not easily swing. Hell, I could hang from it. Loosening the nuts a bit allows the arm to swing pretty freely. Is this correct?

3. Installing Koni - is the top nut holding the shock on a 12 x 1.5. Looks like the nut from Koni is a 1.75 or coarse thread

Lizard928

You do not want the bushing to be able to rotate or it will wear out FAST!

Assemble and install, leave the nuts loose and get the car down to the correct ride height.
You can do this many ways, but leaving the a arm bushing nuts loose will do it (both upper and rear lower).
Then with the car at proper ride height tighten all nuts and bolts. This sets them into place and ensures that they work in the set range.

Pete L

Appreciate the response. I dont have the lower control arm out. So the upper A arm will be stiff when the bolts are tightened???? Understand your comment to tighten on ground especially lower, do you mean upper too?

That is my question, is the upper A arm with new burnings supposed to be "rigid" as the old bushes allowed pretty easy up and down motion and were not badly deteriorated

Lizard928

Oh, one question.

Who the heck is RoDger?

Lizard928

Yes I mean the uppers too. Yours being able to move up/down explains the comment about the metal shavings. You should not be able to move (at least not easily) the a arm in the bushings. If you can, it will wear everything out FAST.

Bertrand Daoust

Thanks Colin for the tip on how to settle the suspension faster for ajusting the ride height.
As I will be doing this shortly (I hope), I will try that instead of driving the car.
A lot faster that way!

Lizard928

Maybe faster, but not easier!!! Try to tighten and torque to spec the lower control arm bolts, and upper control arm nuts without raising the suspension.......

Bertrand Daoust

Just to make sure I understand correctly:
1) While the car is still on jack stands and wheesl off, I leave the 2 upper A arm and the rear lower control arm bolts loose.
2) Put the wheels on and take the car down. As those bolts are loose, the car's suspension will be settle. Right?
3) Mesure the ride height and ajust to were it should be.
4) Tight all the nuts.

Is that it?
Would it be possible to take the car up again after the ride height is ajusted, remove the wheels and then tight the upper control arm nuts as I think those will be hard to reach with the wheels on and on the ground?

Thank you very mutch.

Pete L

Lizard:
Thank You. Did not make sense to me that the new bushings would "stiffen" the upper control arm motion so dramatically in comparison to the old bushings. I can hardly move the upper arm with the axle nuts at each side tightened.

Roger @ 928rus - need to learn to type or proof read better!

Time to put it back togeather

ammonman

Bertrand,
I would still drive the car after tightening the lower and upper control arm bolts to ensure the suspension is fully settled before adjusting the ride height. To access the upper control arm nuts you need to turn the wheels all the way to lock in both directions. This will give you enough room to get a wrench on them.

Mike

Lizard928

Bertrand,

1) raise car with wheels off loosen the two pinch bolts for upper control arm accessable in the wheel well, as well as the 2 bolts on the bottom rear of the lower control arms.
2) attach wheels and lower the car. It may not be 100% at correct ride height, but it will be 95% there as the last remaining bushing (front lower control arm), cannot really be adjusted. If you leave it like this for an hour, or jump up and down on the front end, it will settle that last bit.
3) without removing the weight off the suspension tighten all loosened bolts/nuts and torque to spec.

It is very important especially for the upper a arm that you do not raise the vehicle when tightening them.
If you find it impossible with the tires on, put a good jackstand under the lower ball joint and rest the car on there. But take caution that it does not kick off this. Then let it settle for a bit and tighten everything up.

This is especially important for the upper a arms, but equally important for the lowers.

When you research how suspension (rubber bushings) work. You will understand why many people do not recommend Polyeurathane bushings. A rubber bushing correctly engineered will have maximum friction on both of its mating surfaces. Meaning that it cannot rotate against the outer diameter, or inner diameter. Then when the suspension is actuated (a dip, or lift) the rubber rotates from the inner to outer surfaces. The inner and outer surfaces do not rotate in their housing, only the rubber itself deflects in the center. One of the reasons that Rogers kit has the center metal sleeve is because this results in a much larger surface area for the rubber/flex agent giving it a higher resistance to rotation.

I have seen lower control arms on a 928 where they were torqued town with the suspension not set, and the constant rate of flex (instead of returning to neutral at normal ride height) was so great that it caused the bonded metal sleeve of the bushing to rotate on the aluminium control arm. This made a great deal of noise over bumps and was finally found checking something else.

So again, you want these bushings locked from being able to rotate when the car is at normal road height so that the bushing returns to a non loaded state to increase life, and reduce the chance of slippage. If the bushing easily rotates on either the inner or outer surface it will wear the component rapidly, along with giving decreased performance due to a higher rate of deflection.

Polyurethane has many uses, but in rotating suspension components it is a poor choice and is only used by those who do not understand how it works. A polyurethane bushing will grab the inner and outer surfaces, but it has pretty much ZERO twisting/absorption ability. This causes the bushing to rotate against the metal, where no movement previously occurred. Thus causing rapid wear.
This is why when using these bushings on a swaybar you always get squeeking (and why I use rubber). Same again for upper a arms.
When going to more of a race suspension, spherical bearings are used instead. They rotate freely (suspension settles instantly) but the components ride normally on a PTFE surface with very little friction and are specifically designed for this movement to happen.

I hope that is clear enough.....

Bertrand Daoust

Yes.

Thank you sir.

jon928se

Pete in your 1st post you said there was no crush liner in the old bushings . Did you mean crush tube ? ie inside the rubber of the bushing that mounts on the Axle.

If your old bushings didn't have these it would explain why the new bushings feel nearly rigid and A arm can't be easily moved up and down. You will also be in for a dramatic surprise improvement in handling.

Lizard928

Jon,
The originals do not have a steel liner than I have seen. I could be mistaken on that.
The new design does as it is a revised part and whoever made it feels that the increased surface area was needed.
When using those steel tubes, it is imperative that one ensures that steel tube has sufficient crush so as to not turn once tightened!