I have a 1996 XJS convertible.

I recently swapped out the upper control arm bushings and both ball joints on the drivers side front wheel.

Now when I'm driving, the brakes seem fine, until the last couple of inches of the slowdown/stop. At the final stop, the steering wheel turns itself to the right (clockwise) and the brakes feel like they're sliding, or slipping a bit.

A forceful slam seems to work ok. It only is apparent under a normal slowdown to stop.

Any ideas?

 

Did you keep all the alignment shims in the original locations? Could the calipers have started to act up and its now showing since that part of the suspension is tighter? There is a lot going on there between braking and suspension, make sure all is tight when you go to inspect.

 

Could it be related to the new upper control arm bushings on that side? I can't think of any specific reason why the brakes would be the problem.

I don't know that much about suspension geometry, but I think the shims on the upper ball joint control the caster, which effects the rate at which the suspension dives and rebounds. Again, I'm not sure about this, but it's worth asking again if you put those shims back in the way they came out. It's also possible that the car was aligned and those shims were installed to compensate for the worn components (ball joints, bushings) that you replaced. Now that you replaced those worn components, the shims could be throwing it off.

Checking again to make sure everything is nice and tight is a good idea.

 

I was careful in making sure all the shims were put back exactly where they came out.

Not sure if this could be the problem.

I'll check tightness tomorrow.

Thanks.

 

If the shims were compensating for worn components, and you replaced the worn components with good components, your alignment is off. Maybe this could be the problem.

Does the steering wheel turn itself when the shocks & springs begin rebounding from the stop?

 

Take the thing out onto the highway and do about 4 emergency stops from high speed. Then onto a gravel road if there is one nearby, and do a few 30 mph to stop hard braking. Get the ABS pulsing.

My money is on a sticking ABS-type problem/caliper not quite releasing /pad or rotor slight frictional difference.

Greg

 

Caliper not quite releasing would be my guess.
RagJag

 

Can you not take the car to your local test station and get them to put it on the brake machine? That should give you a reading of the retardation of each wheel and you can compare the readings to the designed specifications. If one of them is obviously lower than the others then at least it indicates that it may only be one caliper assembly that isn't working properly.
If they are all lower than original spec then it points to a more central issue.
Steve

 

Greg,

Could my monkeying around with the stub axle nut have created this problem? (from my bearing replacement thread)

Thanks.

 

In the USA you will be hard pressed to find a brake test stand like in the UK. Most states that have an inspection just have your auto service center do the inspection and sign off on it. Connecticut used to have a safety inspection and did it at state owner stations. They had a brake skid pad device which really did not work. It all depended on how hard you hit the pedal. They got rid of that years ago. Only have an emissions program now.

 

If you jack up the wheel and the wheel rotates OK with practically no drag, except a tiny bit from the brake pads, I cannot see how it would have. Check the rotating feel is the same both sides, as well.

Greg

 

That's exactly what it feels like...so that's that!

 

Looks like I tore the boot on the new lower ball joint I recently put in. I have white grease oozing out.

I must have pinched it when installing the new one.