Weird suspension issue. (Page 1/1)
LS4FieroGuy JAN 17, 09:44 AM
Hey everyone. I've been having an extremely weird issue with my 88 Fiero that happens every time I'm going over 55mph. If I get on the throttle to accelerate it tries to go to the right. And if I let off the throttle it will steer to the left. And what I mean by steer is that I can feel it in the steering wheel and the car starts to gently but suddenly move in the direction that corresponds with what I stated above. I did a complete polyurethane conversion. I did the front shocks. It doesn't have a rear swaybar(yet) and nothing feels loose! It's a very unpleasant issue especially on the freeway. So please any help would be great!

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Joshua Seeger

Vintage-Nut JAN 17, 10:08 AM

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Weird suspension '88 issue / It doesn't have a rear swaybar(yet)



My advice: check out the steering {rack / ball joints} and finish the rear suspension with sway bar end links

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Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles

cvxjet JAN 17, 11:58 AM
I had this exact situation happen back 12 years ago or so; Coming home from work across the San Mateo bridge- which is mainly an absolutely straight causeway- I started noticing it pulling one way under throttle application, and the opposite way during braking...

Was examining the suspension- and noticed one of the struts was LEAKING fluid....removed it and did the compression test....A) No pressure, and B) It did not extend back after.

All of the pressure had leaked out and then fluid was also leaking out.

Check your rear shocks/struts.
cliffw JAN 17, 12:08 PM

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Originally posted by LS4FieroGuy:
I did a complete polyurethane conversion.



When ? Is that when you first noticed it ?

I replaced the lower control arms on my Wife's Rav4 and had the same issue. I had to re-tighten the bolts. Problem solved.
82-T/A [At Work] JAN 17, 01:19 PM
I had this exact same problem in a 2008 Jeep Patriot... (exactly as you explain it with accel / decel and pulling in those directions). It turned out to be the front lower ball joints. I ended up replacing the entire control arms on both sides, which came with new rubber bushings and a ball-joint already installed, and that solved the problem.

If it's a ball joint, you really want to NOT drive it unless you absolutely must. It likely means the ball joint is ready to fail, and that means popping out of the socket. You can test the ball joints by jacking up the car, and trying to wiggle the wheel in and out (from the top and bottom of the wheel). If the wheel moves any way vertically back and forth, then the ball joint(s) are toast. If it moves easily back and forth horizontally (left / right), it's probably the tie rods.
Patrick JAN 17, 03:10 PM

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Originally posted by LS4FieroGuy:

I've been having an extremely weird issue with my 88 Fiero that happens every time I'm going over 55mph. If I get on the throttle to accelerate it tries to go to the right. And if I let off the throttle it will steer to the left.



If it was an '84-'87, I'd suggest checking the cradle mounting bolts. I don't think it's as much of an issue with the 88's solid mounted cradle.

Since it's an '88, I'd say check the long bolt that goes through the rear knuckle. If one or both get loose, the symptoms are exactly what you're describing.
gregr75 JAN 18, 09:27 AM
+1 on the ball joints. I had the same symptoms you had, except it happened at all speeds. The right rear ball joint eventually separted from the knuckle while I was driving 3 months ago the wheel dislocated, and the car swerved luckily I was only doing 15 MPH at the time and didnt hit anything.
olejoedad JAN 18, 09:49 AM
There are no ball joints on the rear of an 88 Fiero.

Long bolt thru bottom of knuckle, bad strut or bad lateral arm bushing are your most likely sources for your issue.
fieroguru JAN 18, 10:20 AM

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Originally posted by LS4FieroGuy:
If I get on the throttle to accelerate it tries to go to the right. And if I let off the throttle it will steer to the left. And what I mean by steer is that I can feel it in the steering wheel and the car starts to gently but suddenly move in the direction that corresponds with what I stated above.

I did a complete polyurethane conversion.



Poly on the rear suspension of an 88 is a bad idea... and likely the cause of the issue.

To start, the sleeve for the lateral links is too thin and when properly torqued will deform/creep. This means you torque it like you should, drive it a bit, and go back to them and find that they are not torqued. Repeat the process, and eventually you will get it to hold torque, but that is due to the poly bushing itself taking part of the load now that the metal sleeve has been compressed.

As the 88 rear suspension moves, the lateral links do not remain perpendicular to the bushing bolts. They are pulled forward and pushed backwards due to the arc of the trailing link. The stiffness of the poly and the over tightening of the bushings due to the compression of the sleeve cause binding, squeaks, and a harsher ride. Rod end lateral links are the way to go. Smooth bind free motion, single torque of the bolts will hold, near zero toe deflection due to bushing compliance, provide better ride quality than poly. The only downside is they are a wear item and need replaced every 10K to 20K miles depending on how you drive your car. https://www.fiero.nl/forum/Forum2/HTML/120882.html

The 88 trailing link is also not a great place for poly for the similar issue of the links following the arc of the lateral links. Add to this the attachment bolts being M14 and in single shear, the poly can puts additional stress on the bolts. Twice that I am aware of this caused one of the M14 bolts to break resulting in a bad day. When rod ends or other metal to metal solutions are used in the trailing link, they typically break as every bump on the road shock loads the connection making for a harsher ride and reduced lifespan of parts. Retaining the rubber bushings in the 88 trailing link is best (Rodney sells new ones). It is also worthwhile to note that shortly after the Fiero, GM switched to M16 bolts for trailing links in single shear on several FWD applications where they only had to deal with braking forces and road irregularities - no acceleration forces.


LS4FieroGuy JAN 18, 12:56 PM
So it looks like everyone is saying that I should buy the kit to fix the bolt holes on the rear knuckle as well as the rear struts. I already checked my front end and all my ball joints and tie rods are good but one of my wheel bearings is starting to go. And for the rear end for maximum performance I should do rubber bushings on the trailing arms and Hime joints for the lateral arms? And on those lateral arms could I technically just make them out of some aluminum round stock? Also when It comes to the rear swaybar should I use zero lash in the bach with the polyurethane mount bushings?