Why is my car jumping around so much in the rear?? I'd love to know.
 

Hey- my first non-engine-related post!!
OK- my car has always felt a little less than stable at high speeds- unlike my previous 2nd gens.
On the highway, whenver I pass someone, and go over the "crown" of the road (opposite lane- the road is slanted opposite, so the car is leaning to the left now, instead of right) The car will suddely take a difefrent steering line after the transition, kindof like if ball joints in the front are shot or something. (they're not- just a comparison)
If I'm on a long sweeper, the rear end will change steering characteristics drastically on and off, depending on bumps and lateral load and start "bouncing" side to side almost, making my car steer in and out (like "bump steer" on a lifted jeep).
Anyways- I was on a back road today, and let it wind out, and as the needle swept past about 210km, I hit some very small bumps, and the whole back end started going from side to side, it felt like by a few feet- Dangerously!!!!
The whole car was twisting from side to side!
I of course immediately slowd down.
The shocks are fine.
It feels like the entire rear end is disconnected, and misaligned or something (only noticable at highway+ speeds, or under long, sweeping turns)
What should I be looking at? Bushings or mounts or something? My experience is with engines, I have never touched suspension.
Thanks guys.

have you had a alignment done at all?

replace the rear toe bushings, even if it doesn't fix the problem it'll help corning.

The aligment *seems* OK, it tracks perfectly, and the wheel is dead center, but that's only a small part- I know.
I'll make a note of the toe bushings.

I replaced my front differential Mount and it solved my problem. But, it ain't cheap. Oh, and yes. the front diff. mount ON THE REAR! No differential in the front. DUH! :D

I have the exact same problem
 

My 90 GXL drives fine normally but as you said at high speed going over small bumps my car tends to get pitched to the side. When I bought my car I figured I would 'try' to drive it through the winter but just the slightest amount of snow at highway speeds and hittin a small bump would pitch my car halfway into next lane. Needless to say I don't drive it through winter anymore. One other thing I noticed: Whenever I reverse with the steering cranked about half way or more it seems like my front tires all a sudden are way out of alignment and you can hear one of the tires sliding instead of rolling on the pavement.

Dude have your rack and pinion system checked by a professional. That could be the reason it does not matter if it is alighned or not. Sometimes when the R/P is fucked up the steering line changes while driving...

Go have your alignment checked soon. If they font find anything wrong, you know you need to look elsewhere for the problem.

I would jack the car up, and visually inspect the front and rear suspension. You might see a loose bolt or something of the such.

From Mazdatrix:
http://www.mazdatrix.com/faq/rrsteer.htm

That could be it- Also- there is no noise or clunks of any sort- just a radical swinging back and forth!!
Way to much movement, the car keeps wanting to go in different directions, and pitch around when I've got cornering load at higher speeds.
I won't be able to look at it soon, as I'm going on vacation, and it's too damn cold here, I just thought this could be a common problem, ya know, someone could say- "Yup, my car did the exact same thing, and I did this....).

I had an 88 GXL, and it was ROCK solid all the time. the rear never pitched around like this.

Thanks

Welcome to the shitty world of DTSS...



-Ted

Great, can I get a T-shirt?

I'll be getting the rear toe eliminators from mztrx for sure.
The installation looks like a pain though- I don't have a press.

I had a improperly installed lateral link on the right side. Has a ball joint at each end. The hub end was not pulled down into its bore resulting in toe out, toe in, toe inbetween etc. Was a real killer in the rain and in hard(heck, mild) cornering. Found it by jacking the rear and grabbing the front and rear of the tires and pull/pushing.
Also, recently a Georgia Boy on this site, found his wagging tail was caused by the rear toe bushings. He described his car as *wagging its tail*.

Yep, the exact sensation.
I guess that'll be it!

I meant to add that the Georgia Boy had just one of his toe bushings fouled up. Evidently had a lot of slop in it. Seems you'd see this type thing if you jack it up and really jerk things around good.

I'll check that
BTW- the reason I post a lot of questions without going over the usual steps first (like jacking up the car and shaking it) Is because it's winter here... pretty damn cold, I am in school, and I have do drive to my parents house to have a facilaties available to do anything mechanical. (swapping engines was real fun)
I just figure I can get a head start on things here first- so I know what I'm looking for....
Thanks everyone.

like they said in the directions, its a good time to do the brake pads. since you have to take it all apart anyway. brakes are a pain, so you might as well have to do everything at once.

hey Ted? do you know if the rear caliper pistons are the kind you push back? or are they the freaking twist and push kind? I hate those.

Just rotate clockwise(no pushing required).