rear suspension noise over tar strips

[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!

[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.

[RandallNeighbour]

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.

Thanks so much for this explanation. It makes a lot of sense to me and may be the reason some of my control arms have worn out prematurely. They were not tightened under load.

[911monty]

Originally Posted by RandallNeighbour

Thanks so much for this explanation. It makes a lot of sense to me and may be the reason some of my control arms have worn out prematurely. They were not tightened under load.

Thanks RandallNeighbor, Glad to be able to return a small ripple of benefit to the sea of information yourself and the many other members have provided by their time and experience to this forum. To quote Retroman "Remember we're all in this together"!

[Pdwight]

Anyone used these ?

[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!

[EJ-Fresno]

I took the car for a test-drive tonight...
What a pleasure not to hear all those noises anymore
Thanks everybody!

[Smallblock454]

Hi,

for those located outside the US or not willing to buy from Pelican.

Porsche 987 part number: 98733104302 and 98733104303
is equal to TRW JTC1316, EAN number 3322937921805

Porsche 986 part number: 98633104307, 98633104306, 98633104305, 98633104304
is equal to TRW JTC1186, EAN Number 3322937753246

The 987 part seems to be a little cheaper than the 986 TRW part. Around 85 euro each.

Regards from germany
Markus

[WillH]

After a ride on some more crappy asphalt I've realized that the front are bad now that I can here it with the rear being quiet. Jacked up the front passenger side and placed some wood under the tire in a neutral position then banged around with a rubber mallet. Droplinks are quiet. The front trailing link is the noisy.
I believe I read that the 987 front trailing links are a no-go. Any upgraded part numbers? If not then I'm off to order 996-341-043-06

[EJ-Fresno]

Originally Posted by WillH

After a ride on some more crappy asphalt I've realized that the front are bad now that I can here it with the rear being quiet. Jacked up the front passenger side and placed some wood under the tire in a neutral position then banged around with a rubber mallet. Droplinks are quiet. The front trailing link is the noisy.
I believe I read that the 987 front trailing links are a no-go. Any upgraded part numbers? If not then I'm off to order 996-341-043-06

I have the same problem, now that the rear is quiet
Is it a PITA to change or it's pretty straight forward?

[winter.k]

Originally Posted by Smallblock454

Hi,

for those located outside the US or not willing to buy from Pelican.

Porsche 987 part number: 98733104302 and 98733104303
is equal to TRW JTC1316, EAN number 3322937921805

Porsche 986 part number: 98633104307, 98633104306, 98633104305, 98633104304
is equal to TRW JTC1186, EAN Number 3322937753246

The 987 part seems to be a little cheaper than the 986 TRW part. Around 85 euro each.

Regards from germany
Markus

Smallblock,

Thanks for the equivalent part numbers from TRW. These are $110 (986) and $125 (987) on Amazon with free prime shipping.

[Pdwight]

for me

part number 98733104302

shows $193.99 each on Amazon