Rear End Knocking and Resolution

[kyngfish]

In my ongoing suspension refresh saga. I was feeling like the car was tight, and handling well, but occasionally when going over bumpy roads or turning, I would hear what sounded like a knock in my rear end. It drove me crazy.

So I raised it up, checked all the torque on all my bolts. Drove again. Knock Knock. Raised it again. Rechecked. Checked the front. Checked brake calipers. Torque. Drop. Drive. Knock.

So I searched in the forums and I saw all the usual suspects. The main theme was that the solve was replacing the rear wheel bearings. The bearings were one of the few parts I did not replace during the refresh, so that might be it.

Then in one of the threads about the bearings, I saw a nugget where one Pelican found that his shocks were bottoming out. Thinking about this, it made a lot of sense. When I did the refresh, I changed the ride height. After redoing the spring plate bushings, I lowered the rear slightly. So I raised it up. Knocking gone. I had the rear at around 24.5” from floor to fender. So I raised it up to about 25 1/8”.

Since most of the threads call out the bearings as culprits, I figured I’d put this little nugget in here in its own thread for future Pelicans like me. And actually, I think the slight forward rake is good for these cars.

Before and After Pics:

[patkeefe]

Thanks Kyng-
My SC has had a weird knock in the rear for awhile. I am going to check and see if the shock is bottoming out. But...I have had these shocks in for quite awhile. Bilstein revalved them a few years ago. I am also fairly low on ride height, but I have reconverted it from a track car, so maybe the extra weight has something to do with it.
Pat

[kyngfish]

For me it sounded like if someone took their knuckle and rapped it on a panel outside the car when I was inside the car. Which is I guess pretty much similar to plastic bottoming out a shock

Usually happened when I hit rough pavement or went over a sharpish bump at slow speed or turned while going over pretty much any bump or uneven ground