Calling all Rear Suspension Experts

[RussMcB]

First two things that popped into mind that can cause those symptoms: Bad shocks, bad toe (especially if the rear toe is far off or uneven side-to-side).

Other guesses: Uneven castor, uneven corner weights (think of a bar stool with 4 legs not the same length), uneven camber, bad tires.

[George Maz]

While tightening a universal strap on the RH halfshaft we, decided to make an adjustment here to help the universal caps seat in the yoke better. This also brought the wheel back inside the fenderwell noticeably...RH wheel was sticking out further than LH wheel.

We restacked the spacers to the top of the Leaf spring, to return to stock height at the rear...no more A$$ dragging ride setup. And adjusted for full suspension travel, just gotta adjust for left side slightly lower than right side as I want the car to look perfectly straight & level.
Thanks Hib & Russ...going to the leaf spacers first was key. The ride has settled noticeably, and was an easy adjustment.

The LH wheel was visually tilting inward, we adjusted it straight. The left rear shock was loose at both bottom and top. Have to access top of shock from inboard, tomorrow. It's no wonder this car was handling like crap. An alignment will be done at some point & Road Force balancing, hopefully I'm getting it closer to where it should look and feel.

[RussMcB]

Originally Posted by George Maz

<snip> Have to access top of shock from inboard, tomorrow.

IIRC (and anyone feel free to correct me if wrong), it's easiest to do this from underneath. You will need to completely remove the shock (not too difficult), remove the FX3 motor, make the adjustments to the top mount on your shop bench, then reinstall.

A year ago when I changed shocks, I think I looked for access to the top of the rear shock from within the car's interior, didn't readily see how to, then decided it was easier to do it from underneath. Fortunately the FX3 wiring is long enough to allow you to drop the shock and gain access to the FX3 motor.

Hope this makes sense. It's from (bad) memory.

It does sound like you'll have a noticeably better handling car when done. Good job.

[Starman]

Originally Posted by Hib Halverson

I skimmed through this entire thread and no where did I see that the trim height of this car is being measured the way the Service Manual says to do it, so, if it were me, I'd do that before anything else.

Also, I read one post saying urethane bushings were installed in the rear.

Bad idea.
C4 trailing and lateral arms need to be able to twist somewhat as the suspension moves. Urethane won't allow them to twist that will bind the suspension at the far ends of the travel.

Now, that's ok for a track car on smooth tracks but a bad idea for a street car.

You either need to go back to rubber or change to spherical bearings.

Just to update and thank all participants again. First to clear up a myth or two: You cannot install the strut rods backward. Urethane bushings work just fine when installed correctly. This was my downfall. Hib was on the right track though. While I was trying to correctly establish ride height. The suspension was bound up due to the fact that you have to torque the connections when it is loaded, near ride height (FSM). I am sure that I tightened everything up at droop years back. Doom on Mikey. To recap:

The spring was reversed and reinstalled, the sway bar was not bent, but I did re-bush it, the strut rods were lubricated and reinstalled - note somehow the cast part numbers on them appear to be randomly applied - there must have been several molds that had the numbers located in them differently. Lubed the tie rods and set the spring bolts to original stock length. Replaced the half shaft u-joints (note if you want to use the correct ones - plan well ahead, no one seems to have them in stock. Found correct AC Delco units at Rockauto, appear identical to original Spicer. Tightened everything up to spec at normal ride height and boom! the car sits and rides correctly.