Brakes Rumbling In 97 850R

xXFaceEaterXx · Post by **xXFaceEaterXx** » 29 Jul 2008, 16:19

I have had a reoccurring problem with the rear of my car rumbling when I brake.
I had my ABS rebuilt first by Victor, thinking that might have been the problem.
Well, it still occurred.
The "TRACS OFF" light comes on randomly and goes off randomly.
Before I assumed that might have been the problem, I replaced the rear rotors and pads since the rumbling is coming ONLY from the rear.
The first day after replacing them, it was awesome.
The problem was assumed to be solve.
Well, the next day, it was WORSE than it was BEFORE!!!
Now, I'm lost...
I don't understand what the problem could be.
PLEASE HELP!!!

Post by **MadeInJapan** » 29 Jul 2008, 16:33

I'm thinking it's actually the rear e-brake (emergency brake)....this is a separate drum on the inside of the wheel hub...check it out. After many years, it tends to rust and fall apart but even before that, it starts to adhere to the side of the hub making a terrible racket. There is a good write-up in the repair database by Lee on this one. For best results in that section, use your BROWSER'S Find feature (it's under the Edit button at the top of your browser). Good luck!

xXFaceEaterXx · Post by **xXFaceEaterXx** » 29 Jul 2008, 16:44

Well, I thought the same thing at first because one of the hand-brake shoes is worn and has absolutely nothing on it.
However, the rumbling DOES NOT occur until the "TRACS OFF" light comes on.
When you first start the car up, the "TRACS OFF" light is off.
Once you start to pick up speed a little bit, the "TRACS OFF" light comes ON, and the rumbling begins...
=/

xXFaceEaterXx · Post by **xXFaceEaterXx** » 29 Jul 2008, 16:46

I also adjusted the e-brake shoe to where they weren't even making contact...
So, it kind of cancels that out...

wolfspiritky · Post by **wolfspiritky** » 29 Jul 2008, 18:01

This is the 850 R I bought. The rumbling/vibration started not long after. THE ABS AND TRACS lights were on when I bought it. I sent the ABS module off to Victor and he worked his magic. After re-installing the module the lights went off and stayed off but, the vibration continued. So, this past Sunday I installed NEW pads and rotors. I did however have to re-use the solid metal shims, with a liberal coating of "disc brake quiet". Now, as he stated above , things were good until Monday night. Now the tracs light comes on and stays on after reaching a speed of 20-25. It had been coming on intermiitently for about 3 days before the new brakes were installed.

The vibrations happens at most all speeds and stopping pressure.

E-brake shoes liners were gone on the drivers side and almost new on the passengers. I made sure I adjusted them as far "in" as they could go. They make no contact with the inner drum now. If they did the vibration would be constant. Vibration only occurs when the brakes are applied.

I did remove the fuses for the main ABS (#9) and ABS pump (#14) with no change.

volvo tech · Post by **volvo tech** » 29 Jul 2008, 22:41

This sounds like you have the wrong shims installed in the rear brake pads. If you remove the rear pads and look at the piston. If the piston is not step, you will need to installed a half shims. If the piston is step you need to install a full shim.