car is eating rear ball joints

billr

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#46
Jack up a wheel and rotate it as fast as you can with one hand, holding a coil of the suspension spring lightly in your other hand's finger-tips. Is it a leaf spring, well try holding a thin part, out towards the tip. Maybe it will work on leafs as well as coils. If the bearings is bad you will feel the vibration, even if you can't hear it. Be sure to try the other side, maybe even the fronts too, to get some comparisons. I know it will be a pain to cut open those old bushings, but I think several of us are eager to see how the parts are worn.
 

mhamilton

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#47
Thank you! It's coils all around, I will try that and see what I find. I think you're right, it almost has to be a bearing, because as I accelerated onto the highway today I heard the rumbling speed up identically with road speed. I certainly believe it's a worn bearing, I'm just surprised I don't feel any play in it.

Do you think it's odd that it rattles like a loose bushing when I go over bumps (gravel or cobblestone)? I don't think I've experienced a bearing doing that before. Only had bearings fail with the growling noise that changed as you turned left/right (front bearing).
 

billr

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#48
Noises can be pretty weird, and when I can't hear it in person I would be really guessing. That's why I suggested that rather easy spring-feel test. It works pretty well, but the vibration can be kind of subtle or subjective; that's why I suggest try all four so you get some comparisons.
 
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#49
When I have my doubts, remove that spring, real easy to find slop with that thing out of the way. But then as you said, if you do find slop, what do you do about it? Buy a new piece of crap vehicle? If you do, will still have problems, but problems of a different nature to make life more interesting. Did drive my Caddy home last Sunday, very quiet without suspension problems, but only drove it 50 mph since I was concerned about the brakes. Well, not that so much, but some idiot pulling out in front of me. Heck, said this time, instead of slamming on the brakes will just cream that sucker. I did average 32.4 mpg. Major problem with this car always has been brakes, but the suspension is great, so they just had to screw that up on your Caddy.

How are your brakes?
 

mhamilton

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#50
Bill, yeah I hear you on that... hard enough to diagnose in person, nevermind over the net! I'll do the spring feel test, but I'm sure it's the bearing. They look rusted enough to have a bad seal and dirt inside, probably need to do all 4 of them on this car.

Nick, I know how you feel. The car is really nice when it's all working properly, but unfortunately that's just for a few moments out of its lifetime. The brakes on this car are slightly annoying. I've got some kind of runout condition causing little vibration. I replaced the rear rotors and pads, cleaned all mounting surfaces, measured runout. The new GM spec for lateral runout on these cars is 0.002". My dial gauge doesn't show any runout on my rotors, but still not very smooth braking. I also don't feel like these brakes work as well as the '97 ETC I drove. Even after multiple bleeding procedures, following the FSM to the letter. These brakes don't bring that heavy car to a stop in any hurry...
 
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#51
Everyone I know has problems with four wheel disks brakes, I had my share of fits with them in trying to combine the parking and service function into one caliper. Not cheap either. My 88 Supra doesn't have that problem, uses disks for the service and the rotor has a built in drum with shoes for the parking function. The pads are inherently self adjusting like the front are.

Just finished with the brakes on my 92 DeVille, full pedal, full power, nice smooth stops. Figure they should be like that for the next five minutes.