loose back end?

Working with a 92 OCC. When driving on the highway, the back end feels really loose, always seems to want to fish tail.. Its even worse with a trailer on. What should I be looking for? It still has working air ride in the back but I think the shocks are worn out. I was thinking maybe worn out 4 link bushings? Car has done it since I got it 2 yrs ago but seems to be getting worse my RMW never felt like this????

maybe just crappy tires,.pump them up to 45 psi,. see what its like,.

Answer these questions, please:

1. Is there any sense of vibration or a pulse, like a regular rhythm to the way it feels?

2. Does it get worse as you increase speed?

3. Does it happen on a straight, flat road, or is it more noticeable in a turn?

4. Does it feel the same in a left turn and right turn?

5. Is it a distinct feeling that the car is actually moving from side to side, like it's wagging its tail, or does it just feel unstable?

Answer these questions and we can give you some better guesses on the cause, or at least rule out some issues.

In any case, you might need a large heavy friend or two to bounce the car to check out the shocks. Buy them enough beer that they really get enthusiastic. Even if shocks are not the cause, they might be shot. The best bang-for-buck I get on these cars when I get one is to dump the standard shock and replace them with something like Monroe severe service, and coilovers in the back. A rear anti-sway bar would come next. But, those are separate affairs from the problem described above.

Make sure you do not buy too many beers, because the "help" may damage the car if they are overly enthusiastic.

A few “guesses”:
Shocks---after the bounce test, look to see if there is any visible fluid leakage from the shocks.

Bad spring or shock air chamber—does the car sit level in the back, both loaded and empty?

Bent rim/ tire with broken or twisted belt. Jack up the car, and rotate the rear wheels by hand, and look at each tire from both the side and the rear, looking for excessive runout. Are the rear tires worn evenly?

Have someone follow you and look for visual clues. Does the car “track” correctly? You can try and measure the distance from the rear wheels to the front wheels. This is best done with a special gauge, but, if you are careful, and have a helper and couple large carpenter’s squares and tape measure, you can come pretty close. Each side should be the same, of course. If they are not equal, possible causes include a bent axle housing or bent trailing link.

I have been driving around with a higher than average load in my 92 OCC, and I have noticed the sway in my car. I think it is inherent in the cars to sway a little with a load in the back. The softness of the suspension is probably the causative factor. The only thing you can do to really enhance the load handling is to upgrade the shocks, and put an anti roll bar on the back. The anti roll bar will not do a whole lot, because it does not change the sway characteristics much, but makes the springs think they are stiffer when the car rolls. The rolling is probably a component of the sway you feel.

A lot of the sway is probably in your tires. The tall sidewall allows for the sideways movement of the car because it is not a solid link to the ground laterally. A taller rim, with shorter sidewalls would probably make it sway less, but then you put more stress on the wheels.

The rear trailing arm bushings, and tubular arms REALLY tightened the rear end of my 94 RMW up when it had 125,000 miles with lots of hauling and towing miles.
Made an enormous difference, it was almost like it swayed going down a straight road.

OK no pulse or vibration doesn't feel like a broken belt or bent rim been there done that... Tires are light truck tires pressure is right up if anything over filled to haul the trailer...I don't feel anything under 40 mph only happens on straight level road over 55 mph its gets really bad always have to counter correct with the steering wheel even worse with a trailer on... yes it feels like the car is wagging its tail... shocks on the back are the air adjust shocks I bet they are original I do have a new set to put in but I cant see shocks causing it to sway like this?

I would put the shocks on. It can not hurt anything. You will know if that fixed it. If not, change the bushings. You can weld a plate on the bottom of the stamped arms to make them stiffer if you need further strengthening.

Thanks Fred I was just wondering if there was a common issue that caused that... I will try to deal with the usual suspects looks like its cheaper to buy the whole arms than the bushings on their own..

The bushings are a pain to install anyway. They will feel like they are loose, and the arms are easy to bend. I would still consider welding a plate across the bottom to stiffen them. I am going to weld plates on mine before I mash the throttle with the 454 (hopefully in the next 2 months).

tailpipe wrote:

OK no pulse or vibration doesn't feel like a broken belt or bent rim been there done that... Tires are light truck tires pressure is right up if anything over filled to haul the trailer...I don't feel anything under 40 mph only happens on straight level road over 55 mph its gets really bad always have to counter correct with the steering wheel even worse with a trailer on... yes it feels like the car is wagging its tail... shocks on the back are the air adjust shocks I bet they are original I do have a new set to put in but I cant see shocks causing it to sway like this?

Thats EXACTLY how my 96 RMW felt when the rear trailing arm bushings were shot.

Yes, trailing arm bushings are rough to install!
All it takes is one "monkey" with a floor jack to jack the vehicle on the trailing arm (with a trailer attached in my case) to bend one. "But that's where I was taught to jack the car!"

I assume that the front end is in good condition, that is, not "toed-out"?