Rear Steer Problem

[mottleemob]

I have a slight feeling of rear steer. Every bush and the upper rear ball joint have been replaced as well as all the bushes in the front . It is better but still has the wandering feeling. Any ideas appreciated.
cheers Phil

[Jimmyb]

Rear track bar perhaps that centre's the rear diff?

[bodgie]

Have the bushes in the lower rear control arms been replaced?

If not, I would be suspicious of the oval bushes, they can cause this sort of problem.

Jason

[JeanLuke]

The WJ/WG does not have a rear track bar. It's what is known as a "three-link" system - a pair of lower trailing arms and the third upper arm laterally constrained (by being a "A" shape). It looks like four links, but technically it is only three.

For what it's worth, I've worked through this on my WG and resigned myself that it is a combination of the geometry and the large tyres. I've gone as far as putting in polyurethane bushes on the lower rear and all new rubber on the upper, yet it still wobbles in the rear like the particular type of girls Freddie Mercury sang about - the ones that "make the rocking world go round."

Geometry is hard to explain in words, but if you think about it, the rear ball joint is up high on the diff housing. When one wheel moves up the ball joint will want to move in an arc centred on the ground half-way between the wheels. This is a fairly long radius, so a small change in angle of the rear axle relative to the vehicle body produces a noticeable sideways movement of the rear. Taller tyres will amplify this because they make the radius longer.

I've gotten used to it and don't notice until I drive my hot-hatch for a few days and get back into the Jeep.

[bodgie]

Originally Posted by JeanLuke

For what it's worth, I've worked through this on my WG and resigned myself that it is a combination of the geometry and the large tyres. I've gone as far as putting in polyurethane bushes on the lower rear and all new rubber on the upper, yet it still wobbles in the rear like the particular type of girls Freddie Mercury sang about - the ones that "make the rocking world go round."

If the lower rear bushes are clapped out this will definitely make things worse. If I were the original poster, that would be where I'd be starting.

I've got superpro poly bushes (the oval ones) in the lower rear with the original rubber bush in the front hole. I've also made a 10mm spacer to help improve the balljoint and pinion angles. The spacer appears to have helped a little with the rear steer challenges.

Shortly I'll be installing another superpro poly bush in the front of the rear control arm, i'm interested to see if this helps improve the situation.

Jason

[mottleemob]

AS mentioned in my original post all the bushes have been replaced. Maybe I will have to live with or get rid of the car
cheers Phil

[bodgie]

I recently made an observation about rear steer.

My caster angle was below spec at 5.36 degrees and the rear end definitely felt like it drove the car quite a lot.

I added some caster angle, probably around 2 degrees but I need to get this checked.

I noticed two things:

1. The steering is much lighter and responsive again.
2. The rear end seems to make less of a difference to the way the car drives, there feels like there is less rear steer effect.

Might be worthwhile checking what your wheel alignment is. May be helpful if it is out of spec.