rear suspension noise over tar strips

[Deserion]

And here I thought it was the clamshell making that racket at low-speed on rough surfaces.

[WillH]

Originally Posted by KRAM36

I just ordered the 986 rear track arms for my car. Now I'm curious to why the 987 is better?

987

986

Asked about the adjustable ones but haven't heard back. Will go with the 986 arms unless there is a reason to justify the price difference between the adjustable ones or 987 ones compared to stock 986

[WillH]

Does anyone torque the frame bolts with it loaded on the ground like the Bentley manual states to do? I put it to 118lb ft with it in the air. Doesn't look easy to do on the ground.

[Pdwight]

I did mine in the air

[911monty]

Isn't the purpose to have the rubber in the bushing in a neutral state with the car on it's wheels? Tightening with the wheels unsupported will continuously load the bushing while stationary and really load bushing in compression over bumps causing premature failure?. While a PITA I usually put on ramps before final torque.

[EJ-Fresno]

So one has to tighten the arms with the wheels on?

[911monty]

The car needs to be sitting on all 4 wheels. When you tighten the bolt thru the bushing, the bushing center shaft is held in that position by the bracket. Control arm movement up and down is enabled by the bushing rubber torquing/stretching around that center shaft. When you load the cars suspension before tightening, the rubber bushing is in a neutral/unloaded position. It can then stretch equally in both directions as the suspension compresses or rebounds. If you tighten without loading the suspension then once the car is on the ground the rubber bushing must stretch as the arm is compressed upward. This has the bushing loaded 100% of the time. When you hit a bump and the suspension compresses, the bushing must stretch even further than designed. The only time the bushing is relaxed is when the car leaves the pavement and is flying. Hope This makes sense.

[WillH]

From my understanding it was a bushing until '99 when they changed to ball. The manual also states that the old type are no longer being manufactured. I guess the vertex re-bush ones would count for those.
I can't see the ball being loaded or unloaded as it can be moved by hand. So I guess I'm saying that this doesn't make sense to me.

Edit.
Might make more sense for the trailing arm at the control arm, though not too sure about that either.

[WillH]

I'm guessing now that the manual is referring to the coffin arm/control arm as it makes no sense for the trailing arm/control arm.
Looking forward to noise free ride to work

[EJ-Fresno]

Originally Posted by 911monty

The car needs to be sitting on all 4 wheels. When you tighten the bolt thru the bushing, the bushing center shaft is held in that position by the bracket. Control arm movement up and down is enabled by the bushing rubber torquing/stretching around that center shaft. When you load the cars suspension before tightening, the rubber bushing is in a neutral/unloaded position. It can then stretch equally in both directions as the suspension compresses or rebounds. If you tighten without loading the suspension then once the car is on the ground the rubber bushing must stretch as the arm is compressed upward. This has the bushing loaded 100% of the time. When you hit a bump and the suspension compresses, the bushing must stretch even further than designed. The only time the bushing is relaxed is when the car leaves the pavement and is flying. Hope This makes sense.

Yes, it totally makes sense.
I have 2 questions:
- I tightened the bolt without the wheels putting weight on the suspension, does it help?
- If I still have to tighten in loaded position, can I just put the car on stands/loosen the bolt/lift the wheel using a jack/tight the bolt? Or I have to go through the whole process again?
Thanks for your help

[911monty]

Originally Posted by EJ-Fresno

Yes, it totally makes sense.
I have 2 questions:
- I tightened the bolt without the wheels putting weight on the suspension, does it help?
- If I still have to tighten in loaded position, can I just put the car on stands/loosen the bolt/lift the wheel using a jack/tight the bolt? Or I have to go through the whole process again?
Thanks for your help

Hi EJ-Fresno. The intent is to have the car resting on all 4 wheels before tightening. This places all suspension components in their loaded state. You could use the jack under the tires, this will get close, just not perfect. Certainly much better than current! Are you going to have the car aligned? If so then maybe alignment shop can loosen and retighten when car is on alignment rack.

[EJ-Fresno]

Originally Posted by 911monty

Hi EJ-Fresno. The intent is to have the car resting on all 4 wheels before tightening. This places all suspension components in their loaded state. You could use the jack under the tires, this will get close, just not perfect. Certainly much better than current! Are you going to have the car aligned? If so then maybe alignment shop can loosen and retighten when car is on alignment rack.

Will do my low-cost way and then get an alignment done to fix any deviation.
Thanks again for all the help!

[Steve Tinker]

When I replaced my front suspension with new arms, links and PS9's, and while the car was still on the jack stands I jacked up he brake disc until the chassis just started to lift off the stands and then I tightened the suspension bolts. It's just replicating the car sitting on its wheels.
That was 10,000km ago and no suspension problems as yet.....

[EJ-Fresno]

Originally Posted by Steve Tinker

When I replaced my front suspension with new arms, links and PS9's, and while the car was still on the jack stands I jacked up he brake disc until the chassis just started to lift off the stands and then I tightened the suspension bolts. It's just replicating the car sitting on its wheels.
That was 10,000km ago and no suspension problems as yet.....

That's exactly what I was thinking about.
Don't put the car on the floor, bring the floor to the car

[Pdwight]

I was able to remove my worn ones with everything up and free, however to get the holes lined up I had to apply pressure with a floor jack for each side.....so this makes even more sense now

[EJ-Fresno]

I just re tightened the bolts using a jack to lift the wheels. It indeed made a huge difference! The ball joints looked already like toasted, so it was really necessary to rework them. Tightened them to 80 lbs/feet, and used blue loctite. Don't think they are going to move for a while...
Thanks for the hint!

[KRAM36]

Originally Posted by 911monty

The car needs to be sitting on all 4 wheels. When you tighten the bolt thru the bushing, the bushing center shaft is held in that position by the bracket. Control arm movement up and down is enabled by the bushing rubber torquing/stretching around that center shaft. When you load the cars suspension before tightening, the rubber bushing is in a neutral/unloaded position. It can then stretch equally in both directions as the suspension compresses or rebounds. If you tighten without loading the suspension then once the car is on the ground the rubber bushing must stretch as the arm is compressed upward. This has the bushing loaded 100% of the time. When you hit a bump and the suspension compresses, the bushing must stretch even further than designed. The only time the bushing is relaxed is when the car leaves the pavement and is flying. Hope This makes sense.

Didn't even think about this. Good bit of advice. Would putting some jack stands just on the suspension and lower it mimic the car sitting on the rear wheels?

[Pdwight]

Kram I had to do this to get the bolts in the rearmost attachment point. I put the arm in place and the front tough bolt and then jacked up the rear link just inside of the rotor until the holes lined up.....the car was all but fully supported when I did this by the jack under the rear link.......this has been a great thread.

Back when I was doing this a member on here gave me the 987 part #s for the arms, he said they were built much sturdier than the 986 arms and he was a regular tack guy as memory serves me.

[911monty]

I have seen cars that were several inches over their stock height after suspension rebuild because they tightened their bushings while on jack stands. The bushing becomes a rubber spring!

[KRAM36]

Originally Posted by Pdwight

Kram I had to do this to get the bolts in the rearmost attachment point. I put the arm in place and the front tough bolt and then jacked up the rear link just inside of the rotor until the holes lined up.....the car was all but fully supported when I did this by the jack under the rear link.......this has been a great thread.

Back when I was doing this a member on here gave me the 987 part #s for the arms, he said they were built much sturdier than the 986 arms and he was a regular tack guy as memory serves me.

Excellent. I have mine sitting here. Just waiting on the new struts and shocks to get here before I start, already have new springs waiting too. You're right, great thread.