87 BII Bump Steer/Over-steer Problem

[ab_slack]

Pretty much stock front end on my 87 BII

I've recently encountered a problem with the steering. It seems to be most prevalent when I hit some bumps or an unusual direction change in the road surface affecting one wheel but not the other. Such as might be near a storm sewer.

In most cases it makes a very definite pull to the right. It doesn't just drift that way independent of where the wheel is pointing, but I can very definitely feel the pull in the steering wheel. When I correct it stops. It isn't necessarily changing my direction a whole lot but I feel if I weren't holding the wheel and resisting the pressure it probably cause some change in direction.

It has not exclusively been a pull to the right. It has pulled to the left although much less frequently with the same feel in the wheel but opposite direction.

In most instances steering is well behaved. Normal return to center coming out of turns. No vibration in the wheel at any speed.

Could this be a basic alignment issue? Its been a couple years since last alignment, I could have hit some nasty bumps.

When this started happening I took a look at the steering. I found the coupling between the pitman arm and the tie-rod to have a significant amount of play. So I replaced the tie-rod and while at it the inner tie-rod end for left hand wheel. The outer tie-rod ends I had replaced a couple years ago.

The only difference correcting that problem really made was the steering got a bit tighter and now I very definitely feel the pull in the wheel while before it wandered without as much feel.

The wheel bearings and ball joints seem to be okay.

I had a similar problem a couple years ago with wandering over bumps and un-even pavement. That turned out to be one of the tie-rod ends and when replaced steering was really precise.

I thought perhaps one of the new outer tie-rod ends is no good. They seemed okay when I looked though.

Any other thoughts what might be going on?

 

[4x4junkie]

It sounds to me like something under there might be loose and moving around.

Have you checked things like the radius arm-to-axle bolts? Axle pivot bolts? Steering box-to-frame bolts?

Also, if you haven't already, you might jack it up and make sure everything moves smoothly from lock-to-lock (make sure nothing is binding, etc.).

 

[ab_slack]

I haven't resolved this yet, been very busy but I think I might have found the issue.

No binding anyplace.

I got a camera on a magnet and put it in various spots on both the right and left, forward and behind the wheel. I can see nothing moving in an abnormal way with the ball joints, radius arm to axle bolts, axle pivot bolts.

What I did see was on the driver side the radius arm, over bumps, the entire arm seemed to show quite bit of up/down movement. Of course at the wheel end it must move with the wheel, but the other end I would expect much less movement. Passenger side acted as I expected.

I put the camera to look at the radius arm bushings and the driver side is moving around a huge amount. Both sides move back quite a bit when braking. I would expect that as they see the entire braking load, but driver side moved back so much that clear space opened up between the bushing.

The way it turns I would have thought the problem was on the passenger side, but perhaps I have the front end biased to compensate for a leftward turn and the pull right occurs when the left hand arm shifts into a more normal position.

I want to take a look at see what condition the metal is underneath the bushing.

As far as replacing the bushings, not sure how difficult that is or what tricks there are to it.

I've suspected problems with the bushings before but could never get them to move which suggests there was probably some load on them, so I am not sure if I am getting in over my head.

Thinking about it, perhaps the springs end up insuring some load is always on those bushings.