Hi all - you folks did such a great job helping me figure out my last problem that I thought I would try this again.

Sometimes - only sometimes - when I break, I get a "buzzing" or "vibrating" noise from the rear of the car. It's a lot worse and happens a lot more often when there is a lot of weight in the back seat and trunk. I recently had three passengers and their luggage in the car (with one very large passenger in the back seat) and the break noise happened almost every time I used the breaks.

With just me in the car, it only happens ever so often. It's a very strange buzzing noise. Is it the breaks - do I need new rear breaks? Is it the ABS? Is something wrong with that? It's almost like the ABS has engaged for no good reason.....

Help!! Thanks

Kathleen

If it is th, at your best guess, a brake related issue, I would first look at the ABS. Sound like a possible culprit to me. It could be attempting to engage due to over exaggerated weight imbalnces.

Out of curiosity, how long have you had the car, and if for quite awhile, how many times have you changed the brake pads up front?

Usually you will go through several front brake pad changes before the rear needs to be changed, as most normal stopping puts the greatest work on the front brakes. A major load imbalance could alter the typical ratio between front and rear,especially if the rear is holding more weight to the ground, and in the case of alot of difference can lessen the grip of the front tires, causing the ABS system to think the front tires are loosing some traction. This is only a pure guess though.

Usually when the ABS kicks in properly you should feel a pulsing while the car slows down or stops. Do you notice any kind of pulsing?

I'm still fighting an annoying random brake squeeking in mine since the day I bought it and have yet to find what is causing it. I;ve replaced all the rotors and pads and used all the anti-squeek I can, and mine still drive me nuts...haha

Is it really just a buzzing sound or a vibrating one?
By buzzing, you're implying its noise level is low.

If yes, then clean the ABS sensor at all the wheels, particularly from the back. Sometimes, a stuck caliper (can be rebuilt byb just changing the seals) can also produce a low noise, as much as a loud one.

The noise is a vibration - and it's pretty loud.

Kathleen

Well, in THAT case, look at your shock mountings, your shock absorbers themselves, and also the rubber bump stops to see if they got loose or something. If you started having the problem or if the problem escalated after taking in huge loads, my guesses are just so, as above.

Just took care of the vibration, squeaking, etc. entertainment with the brakes. Go to the Volvo dealer and purchase a "Service Kit" (Volvo part number 272272). It contains 4 brake pad shims. Replace the shims on your rear brakes (use silicone grease on both sides of the shim) and problem solved. Ket was 13 bucks or so.

My soccer-mom-mobile screamed on occasion during gradual braking - no longer.

OR if you cannot afford it, use tin snips to cut away the bottom half of the brake SHIMS (leave the pin guide holes alone) and that should work as well.

Volvo has a service bulletin for this. Good luck.

Check your rotors!!! I actually just had this problem with my 850 glt sedan, and my rotors were pretty badly grooved. Changed the rotors and the noise is gone.

But I know what you mean. It can be incredibly loud, and embarrassing! Mine could be heard from other cars! Mine seemed to be affected by higher temperatures.

Hope this helps!

As you can see Kathleen, there're a few possibilities.
:)

Rear Break rotors were badly grooved - that was the issue. Service station replaced them and I'm good to go.

Thanks everyone - as always - you have GREAT info here.

Kathleen

Thanks for the update.
:)