Rear Brake...judder.

[Free2Drive!]

Hi Volvospeed

Recently a mild judder from the rear axle has appeared at low speed when I apply the brakes.

This has slowly gotten worse and now happens at any speed up to 50 mph.

So, should I replace the pads/shims, or is it the rotors? How do I tell?

The pads have a lot of wear left on them so could I just re-insert new shims?

If I need to replace the rotors then I will replace pads as well, do I also need new shims or will old ones be good?

Finally, if I have the rear rotors off then should I replace the hand-brake lining as well?

Look forward to your thoughts.

Matt 1993 850 GLT auto 155,000 miles

[Free2Drive!]

Should add post-script....

This is definately judder/vibration NOT pulsation..

Thanks again...Matt.

[BlackT5]

I used to have a 93 850 and I had the same problem. The only thing that fixed it was having the cutout shims installed.

[drej1]

Could be the "rear " emergency (hand brake) lining that has come off?

ours did...

(you have these rear disc's right)

D~

[CA855R]

The easiest thing to do is to install the cutout shims. See Bay 13 in this site for details. Just be sure to add a lot of silicon grease to the shims and it should take care of the problem. Might as well change the pads if they have been changed in awhile. Easy .5 to 1 hour fix for both sides...

[KLS]

How do the antisqueal shims cause brake judder?

The parking brake lining coming off the shoe inside the brake rotor "top hat" must have been an interesting find.

The only time I've had the rear brake judder was from pad material deposited onto the rotor surface. Sanding the rotor surface and the face of the pads fixed it for a short time, but new rotors with a different material was the fix.

Ken

[Bay13]

How do the antisqueal shims cause brake judder?

The cut out shims don't cause it they get rid of it. The vibration or resonance would be a better term is like the wine glass trick where you rub your finger around the rim of the glass and get it to resonate and drive everyone at the Wedding crazy. Well the same thing can happen on the 1993 to 1997 FWD cars. Volvos solution was to install the cut out shim which offset the pressure the caliper piston put on the pads and that eliminated the problem. If you have glazed rear rotors and pads you might also have to replace the pads and rotors. In 1998 they just built the cut out into the caliper piston.