Self Centering problem

[Sparticus]

Following my preivous post about failing the SVA of about 8 points one of which was self centering steering i was given some advice about moving one of the shims on the upper front ball joint. Today i jacked the car up, scribed the locations of the bolts then took out the shims on either side of the car and i now have them both at the front of the ball joint.

However, the steering STILL isn't self centering (or making virtually any attempt to do so). Any idea what the problem could be? the SVA guy didn't really seem happy with the lower UJ where it connects to the rack (its new from DAX) it seems to be either worn or fighting against the rack he seemed to think. Can I have ideas ASAP, i'm missing all the half decent weather?

Thanks again

Si

[TINKA]

Sorry but to give any useful information It would be a lot easier if you could post a picture of exactly what you are on about.

[wilf]

If it is set up exactly as DAX describe, the geometry should be OK. Enough Dax's have been through SVA without a problem.

Sure you have the wishbones around the right way?

[Sparticus]

dax built the rolling chassis, so it "should" be okay , without bits the wrong way around. I'm getting the feeling my rack is still too tight orrrrrr i have sone sort of problem where the lower UJ meets the rack. SVA guy said the UJ seemed to be worn or that the forces were fighting against each other or something. Might mean i have to reduce the length of splined rod between the 2 UJs between the bulkhead and rack (its not power steering).

Its difficult to show the potentially offending bit in video but will make an attempt.

Si

[slogger]

Originally Posted by Sparticus

Following my preivous post about failing the SVA of about 8 points one of which was self centering steering i was given some advice about moving one of the shims on the upper front ball joint. Today i jacked the car up, scribed the locations of the bolts then took out the shims on either side of the car and i now have them both at the front of the ball joint.

However, the steering STILL isn't self centering (or making virtually any attempt to do so). Any idea what the problem could be? the SVA guy didn't really seem happy with the lower UJ where it connects to the rack (its new from DAX) it seems to be either worn or fighting against the rack he seemed to think. Can I have ideas ASAP, i'm missing all the half decent weather?

Thanks again

Si

Just a thought that springs to mind. Have you got the lower wishbones fitted on the correct sides of your chassis?

Arr. I see that Wilf has pointed this out. I'll learn to check the thread out first.

[maurice butler]

self centring is controlled largely by caster ange. increase it to increase self centering. thats why the question above about having the wish bones on the right side. if you are using jag bits you can have problems mixing bits from different series which end up with next to no caster angle.

Maurice

[Sparticus]

Ok i've tried to put on some pictures from earlier in the build so you can see the suspension and steering setups i have. Hope it helps :S

Si

[Nobby]

Si, have you tried disconnecting the track rod ends to see if the front wheels are difficult/notchy to move (with the car jacked off the ground)

This would show if the top and bottom balljoints are OK or tight. Plus it's possible that the steering rack is duff or damaged. With the track rod ends diconnected is the steering stiff or smooth from lock to lock? I've heard of 2 (Dax) people who've had new racks that were damaged.

Have you got the caster shims in the right place and how many are there?
May be neccessary to add/subtract some?

Cheers

[Sparticus]

have both caster shims to the front of the upper front ball joint. is now no place to fit any more shims in. Will try jack the car up and check for notchyness.

Si

[Happy Jim]

If the UJ's on the steering linkage are fighting each other that would be enough to affect the self centering. Jack the car up and spin the steering wheel from lock to lock, any rumble/grumble would indicate more work required (either in the orientation of the UJ's on the splines (relative to each other) or as you say the length may be causing it to bind.

Rgds

Jim