Jfrahm

Hi all,

As my 1992 has 160K on it I want to check out my rear suspension. Any suggestions on what to look for, places to pry for deflection, etc? I have no clunking or anything but I feel the car feels unsettled and tramlines more than I like.

Thanks,
-Joel.

V2Rocket

tramlining is largely a function of tire pattern/alignment.

mine went away entirely when i switched from BFG g-force tires to falken 912s.

as far as suspension wear...it's probably worn regardless, after 160k miles and 22+ years of heat cycles.

would it be excessive to use a come-along attached to a trailing arm to check bushing deflection?

Elephant Chuck

Based on age and mileage, the spring plate bushings will be toast.

Measure the gap on the spring plate tube portion where it pokes through the spring plate cover. It's supposed to be concentric. You will find the gap up top is less than the gap on the bottom. Do the measures with the wheel loaded at static ride height. In extreme cases the spring plate will contact the cover plate.

This non-concentricity is due the bushing be deformed and worn. It no longer functions properly when this happens.

Jfrahm

Thanks, I will look at the spring plate bushings... but would not a loaded bushing have some deflection regardless of age?

I dunno about a come-along but a ratchet tie-down might be employed. No idea how I might tell if I am putting on, say 500 lbs of force or 1500 without a strain gauge.

One thing that might work: I could put the parking brake on and pull the whole car forward and back while measuring from fixed points to the wheel center. I could not really bend anything that way as I'd be limited by traction and brake effectiveness. If the parking brakes are not good enough I can use the mains and park the front wheels on some cereal box cardboard.

If one had a steep driveway this would be really easy, just hang the car off a come-along or ratchet strap (with a backup tow strap and nearby chocks for safety) and lower it a bit with the rear brakes set, then measure the rear toe and the wheel center wrt some fixed points, then pull it uphill a few millimeters and measure again.

An old tire a few inches away to catch the car if it gets loose would be sensible.

-Joel.

Elephant Chuck

Good bushings deflect very little. They will appear concentric to the un-aided eye.

V2Rocket

howabout throwing some weight in the trunk and checking the bushing deflection as the bars twist?

an engine crane would be very helpful there.

Jfrahm

Update: I have not tried loading the rear suspension fore-and-aft but I did look for deflection of the torsion tube bushings. There is less than 0.5mm difference top to bottom, so I think they are OK. I could not find any other signs of significant wear.

I think I had too much rear toe and some cross camber. I believe I have a better rear alignment now and I will get more driving data soon. I have new tires but I want to get everything sorted before I put them on. The old tires might never handle right at this point but I still want to see how good I can get it.

divil

Too late now I know, but for future reference, put your new tires on before alignment. It's quite possible you'll need to have the toe adjusted again with the new tires.

Jfrahm

Hmmm, OK. I am doing my own alignment, and will be checking tire temp across the tread to make sure I am not excessively wearing the new tires.

I suppose there might be a way to measure toe that would change with different tires but I have not quite clicked on what it would be.

divil

If it's the issue I was thinking of, you would know immediately. What happened to me was that when I changed tires, the steering wheel was no longer centred. The car still actually tracked straight though. I don't really know how that can happen but it did. I believe the fix is just to make identical adjustments to the toe on both sides, so if you're doing your own alignments I'm sure it will be no problem for you.

V2Rocket

I checked my T-bar bushings yesterday after reading this thread...mine are toast.

Elephant might be getting some $..