Sloppy rear end

[gadget73]

And no, I don't mean your sister's. Ever since I got my new rear tires and especially since the wheel came off I've noticed the back end of my car seems sloppier than before. Perhaps its always been like that, but I didn't notice because of the bad tires or something. I can feel it kick sideways when it shifts, and going over bumps makes the rear end noticeably jump to the right. Running at highway speeds it feels almost like I'm on ball bearings because it randomly seems to shift left-right in the back. Tires were at 35 psi, and I dropped them to 30 thinking maybe because they're slightly wider than stock (225 70 15) that the higher pressure was reducing my contact area. That didn't seem to help any. I backed it up on the ramps and gave everything a quick visual inspection but nothing looks bad. I'm thinking perhaps the rear control arm bushings or the bushings for whatever that piece is at the top of the rear that keeps it from going side to sode (watt's link?) are toast. Anyone else have suggestions on what/how to check back there?

[DuceAnAHalf]

you dont have a watts on a 86. the upper control arms control side to side movement

[gadget73]

I'm informed the part I refer to is the trailing arm. So it has two control arms that attach where the shocks and springs are, then the other one to control lateral movement that attaches to the top of the differential itself. Its the one that controls lateral movement that I suspect has bad bushings.

[grandpaslincoln]

Jack the car up by the frame try to move the rear axle back and fourth, see where the sloppyness is coming from.

[gadget73]

I don't have a decent jack or set of jackstands here at home. Just the ramps. I can probably put it on the lift monday at work.

[grandpaslincoln]

Sucks not having the tools you need. Ah, putting it on a lift would be safer anyway, no chance of it falling off if you decide to get carried away with the rocking of the rear end lol.

[boXman]

Gotta be careful shakin your rear end too hard....

[slack]

Sorry, I know... zombie thread of the year right here.

I have the same issue going on in my car. On my way to work, I hit some rough spots in the road while turning and the car basically felt like it was skating sideways in the rear end. Tires have a ton of meat on them and they should have held the road fine. I was going probably under 15mph. Rear end has shocks and springs less than a year old. Front end is all brand new except for the control arm bushings.

Straight and even driving, the car is fine. Potholes are currently dangerous at highway speeds though. (Especially if I don't hit them going directly straight).

I've had the car aligned twice. Both times it checks out fine.

Gadget, what ended up being the solution for your car? Or does anyone have any ideas where I should check next?

[sly]

I'd check the rear control arm bushings. If those are shot, it'll still bounce around. And I've had shocks blow on me inside 6 months... so check them and make sure they aren't leaking. Give the rear a static bounce test too and make sure it centers up quick and doesn't overshoot much, if at all.

[gadget73]

wow, here's an oldie LOL.

Mostly it was all 4 control arms had very dead bushings. If you have considerably taller than stock springs and stock shocks, you may also run into situations where the shocks hit the full limit of their travel and the tires basically lift off the ground for a moment going over big potholes or bumps. Thats a sort of differently scary feeling, but I've had both issues.

[IPreferDIY]

I recently did most of the suspension and steering joints and bushings on my 2000 Grand Marquis. I started with only the joints in the hope that I would not have to do the bushings, but one of the lower control arm bushings was creaking so I changed those. Only then did I gain an appreciation of how important the bushings are in these cars. The front end felt a lot stiffer and looked a bit higher, but it still creaked and felt like it needed something else. I ended up doing the upper control arm bushings on the front and also the rear control arms and Watts link. I had heard the rear creak at one point, so I figured those bushings were bad too. I also had a weird effect when sitting at a red light and being blown by a gust of wind. It was a really weird wavy motion from side to side. I presumed that was a Watts link issue. I only had a small amount of the side to side problem while driving, though it was noticeably improved after doing that third round of work. Even then, I still had to do my front stabilizer bar bushings. Those were in really bad shape. Here's a link so you can see for yourself: url]http://www.grandmarq.net/vb/showthread.php?51161-Corroded-Stabilizer-Bar-How-Bad-Is-It[/url]. I'll be doing the rear stabilizer bar bushings and links soon for good measure.

It seems to me that when one of these bushings needs attention, they should all be done. The rubber is the same age, and they've all seen about the same kind of relative strains. I just hope I don't have to get into the body mount bushings now.

Fortunately for me, my shocks did not show any indication of needing to be replaced. Since they can be done so easily as a separate repair, I just left them. I've heard of people changing springs, but I didn't see any need for that. Considering that I obtained a significant increase in ride height from changing just the bushings, I have to wonder whether some people erroneously attribute bushing issues to their springs.

[slack]

Hmm. So it looks like the votes are for the bushings.

I have a new set of energy suspension front control arm bushings that I'm waiting for a nice weekend to get in. I'll check the rears. The fronts I know are bad, I guess it would make sense that the rears would be in similar condition. I'm guessing my new heavy duty suspension might have just made the bushing issue more pronounced as now the suspension is much stiffer. (as well as a bit higher). I think I read that swapping out the rear bushings is more of a pain in the ass than the front ones...

Thanks for the info guys. I'll let you know what I find!

[IPreferDIY]

... I'm guessing my new heavy duty suspension might have just made the bushing issue more pronounced as now the suspension is much stiffer. (as well as a bit higher). ...

This makes sense to me.

Something that came to mind when working on my car was that simply jacking up the car might be enough to send worn control arm bushings over the edge. When you consider that the bolts for the control arm bushings are supposed to be tightened up when the car is at normal ride height, and then consider how much the control arms move when the car is jacked up or on a hoist, the resulting strain just can't be good for worn bushings.

Please do let us know what you find. I like learning how things turned out.

[87gtVIC]

The rear bushings were not horrible. The ones in the arms are cake. Tale the arms out and light up the tourch, mapp gas, etc and have at it. Make sue to do it on a surface you don't car about. Lots of black expandable worms coming shooting out and the grand finale is the entire bushing bursting out.

The one in the pumpkin was a PAIN. Had to be careful heating that one up because the fuel take is right there. I got it hot enough to take a punch and push the guts out. I have a permanent wire wheel for cleaning out the holes now. That rubber just sticks to everything once heated up. lol

[sly]

That rubber just sticks to everything once heated up. lol

QFT!
I destroyed a set of work clothes (the dirty work kind of old worn out jeans and t-shirt, but still absolutely ended them) when I did my front bushings. Never have done the rear.. I just use it as an excuse to power slide it with the limited slip in the rear.