At 07:48 AM 12/30/02, Steve Bowling wrote:
In the reassembly phase of replacing the front shocks on my 1986.5 (S4 suspension), I ran across a note in the repair manual regarding the bolts that secure the bracket (called a "bearing clamp" in the manual) that is the rear lower control arm mount. It says to "screw in until only 2 threads are visible. [Don't torque down] until assembly is completed and springs have settled."
The threads are not visible once you stick the bolt in the bracket, so I suspect this means essentially untightened approximately two revolutions from torqued-down. Is that correct? That seems pretty loose to be supporting the weight of the car. And, when the "springs have settled" I assume that this means just resting on the ground, not after driving around for awhile - correct?
The reason for this sequence is to prevent tightening the clamp on the rubber bushing while the arms are at full droop. The rubber bushings act as bearings to absorb the rotation of the arms with suspension movement. If you tighten them with the arms down, the bushings will fail because they are having to absorb twice as much rotation when the arms move to the full up position on a bump. In other words, if you tighten them more or less in the middle of the travel, they never have to absorb more than half of the rotation.
The clamps and bushings don't hold the weight of the car, they just hold the inner end of the arm in position.
Regarding tightening of the inner lower A-arm bushing clamps:
I just did the motor mount replacement, requiring the removal of the said A-arm bushing clamps. I torqued them with the car up on the stands I made 47 years ago in high school welding class. With the arms hanging down.
So are you saying that it would be a good idea to loosen those clamps
while the car is sitting on the wheels and then re-torque them? I will
do it if you say it is necessary.
I would. No cost, not much work, might well prevent ruining the bushings.
OK, you guys. I did it. As soon as I loosened the bolts holding the aluminum "bearing cap" down, the car dropped down three inches. I had to use a mirror to be able to see the dial on my torque wrench as I retightened the bolts to 88 pound-feet as shown in my microfiche manual. I went for a road test and the handling was markedly improved,
allowing me to develop at least ten more G's of cornering force. I picked up about 18 miles an hour in top speed, and noticed also that the gas mileage had improved. Young girls waved and beckoned as I drove by, and this has never happened before. Finally, at a stop light, a guy next to my left side rolled down his window and offered me $78k cash for the car and he would throw in his 99 Lexus. I turned him down because there was a ding in the passenger door.
I appreciate both you guys recommending this small job. Thank you very much.