Front End Shake Puzzle

[davew833]

The front end of my '94 LS FRONT wheel drive has begun shaking intermittently at about 60 mph on the freeway- more on curves. It shakes hard for about a second and a half and then stops for half a second, then repeats. It's perfectly smooth up to 60 and smooths out again somewhat around 70. The other night I removed the front wheels and checked the ball joints (with a pry bar), checked the tie rod ends, struts, etc., and found no wear or play anywhere. Then I rotated the tires front to back to see if that would change anything. I got the same oscillation even after doing that. So, I took it to a nearby tire, brake & muffler shop this morning. They spent about 90 minutes trying to diagnose it and couldn't find anything deficient in the front suspension either. They did show me that my right front tire had a little wobble when spinning that indicated a tire with separating belts and/or a bent rim. Tonight I swapped that one out with a spare wheel & tire I had and it made no difference. Vibration seems to be worse under acceleration than coasting. I'm stumped-- any suggestions?

[Subix]

If for whatever reason changing the tire out doesn't resolve your issue, find a shop that uses a Hunter Road Force balancer to better pinpoint the problem.

[intelisevil]

I had something similar happen on my Exploder in the past. I'd be driving along and the steering wheel would rip out of my hands, jerking back and forth . . . not fun at freeway speeds on curvy roads!

I had done some front end work replacing tie-rod ends, ball joints, etc. What had happened in my case was that I had moved the steering rack back and forth several times during the work with the engine off and got some air into the system. The fix was to sit in place (in gravel or loose soil is the best) with the engine running and slowly turn from full lock to full lock and back a few times to get the air worked out.

Good luck, I hope it's a free fix like it was for me!

[davew833]

I thought about it being air in the P/S system because I just replaced the timing belt and water pump and disconnected the P/S return hose in the process. I hadn't noticed the problem before that.

I replaced the P/S tank O-ring, filled it up and cranked the wheel back and forth a bunch of times with no effect on the problem. Maybe I didn't do it enough to clear the air out of the system, or it's another problem.

[B 4 You]

I had a similar thing with mine. Did you check your air pressure? Also, take the ball joints all the way out and fiddle with them to see if they're worn out. When I replaced mine it stopped every little shudder.

[davew833]

Well, I bled the power steering again by finding some loose gravel and turning the steering wheel from lock to lock about 40 times rapidly-- it was a good arm workout. That seems to have reduced most of the vibration at 60 mph so I'd say at least part of the problem was air in the system. The remaining minor vibration feels like maybe a wheel out of balance which is easy enough to correct. Thanks to Dan for suggesting it's better to do it in loose gravel or dirt.