'98 Cadillac DeVille - Rear suspension problems

So, I already had a (terrible car) Chrysler PT Cruiser bite the dust this year and now my loaner car — for the time being — is also having issues.

For about three months I’ve been driving around town (NOT on highways) in this Cadillac and the back end of the vehicle feels like it’s rolling from left to right as I drive. It’s not bad at 25mph, but on expressways where the speed limit is 45 to 50 mph the car wobbles so much I look intoxicated.

I finally brought it in to a shop to see what the deal was and they tell me the rear-upper knuckle and bushings need to be replaced: “they are worn and very loose.” They also explained to me that I can’t buy one without the other (knuckle without a bushing and vice versa). Then I asked how much that repair might be and the garage said the estimate was $2,163.

Flabbergasted, I asked why it was so much. They told me it was because the parts that need replacing will run about $750 each (and I need two, I guess) plus labor and wheel alignment.

First big question: Are they just trying to take all my money? I did a few google searches and found results varying in price (between $35 and $280) for the part I think they’re talking about.

Secondly: If they’re asking too much, how much should I expect to pay?

Thirdly: This Cadillac has 137,558 miles and a few other minor issues. Is it worth fixing at all?

I would take the car to a shop willing to put it up on a center-post lift and show you exactly what is worn out and needs to be replaced…Get a repair estimate from THEM…This is not rocket science, this is plain nuts and bolts parts replacement…BUT, many of the parts are listed as unavailable…This rear suspension is somewhat unusual in design…Does yours have air springs? That complicates things somewhat…

http://www.gmpartsclub.com/parts-catalog/cadillac/deville/1998/base/4-6l-v8-gas/rear-suspension/suspension-components

I believe it has coil springs. I’m not 100 percent on that, but from what I’ve read the base model DeVille does not have air springs.

After replacing something like this is the wheel alignment necessary and/or a good idea?

It may take me some time to find a garage that will do this for me, I’ve been to a few different places in town for other repairs and each one seems very stingy with their time and willingness to show rather than tell. In most cases they only want me to pay.

Have you tried checking the shocks? Bounce each corner, see if one is bad.

They seem to bounce okay.

I should add: I notice the wallowing back and forth the most around corners or bends in the road. Occasionally, while driving, it sounds like my back tires are loose. Other than that feeling of not having control over the rear wheels — in a rear-drive vehicle, mind you — the ride is still pretty comfortable…much smoother than an older Corolla (for example).

The rear suspension is independent. There are upper and lower A arms with rubber bushing on the inner portion that RARELY wear. The bushings cannot be replaced so u need new a-arms. But there are many used ones in junkyards that are very cheap. The outer portion of the a-arm has another bushing which is referred to as the knuckle bushing. These CAN be replaced. There are upper and lower knuckle bushings and they are about $40 each. Any shop can press in the bushings. It’s easy to do an online search for caddy knuckle bushings. I have replaced the on my car.