brakes for 850R

chriskose · Post by **chriskose** » 27 Oct 2002, 17:34

Has anybody had experience changing the rotors on the 96 850R model? I guess the brakes would be the same across the 850 model range... There is a vibration when the brakes are applied at highwah speed >60 mph and again below 35 mph. I assume the rotors are warped. Also, would the pads need to be changed as well?

Post by **matthew1** » 28 Oct 2002, 18:15

I spoke to a 25-year Volvo tech on Saturday about this very topic. I asked if I should take my rotors in to have them planed (smooth the ripples). He said to bring the whole car in to a reputable Volvo shop and have them lathe the rotors while they're on the car. Much better accuracy -- but it'a newish procedure so not all shops have them yet.

As far as pads go, they're a seperate issue. If they're in need of replacement, replace them. If not, keep em.

As always, I recommend OEM brake parts.

Volsey · Post by **Volsey** » 23 Jun 2003, 02:45

The pads may or may not be warped. I used aftermarket pads (from a reputable and high quality company) on my last brake change. After the change the car shuddered like all hell on the freeway (while braking). When i was measuring the rotors for warpage, i noticed that the pads didn't sit right. i applied quiet-stop to the backs of them and the problem vanished. one other possible problem would be your ABS wheel speed sensors. when one or more are dirty, they give false signals to the control unit and the system engages anti-lock braking. this can often feel like the tires are skipping or bouncing and the entire car feels like it's going to fall apart. These can be checked and cleaned by pulling the wiring harness that connect to the hub of each wheel and removing the bolt that holds the sensor in. then clean the tip surface and remove deposits. be careful not to jar the sensor though.