Replacing rotors

gtg737m · Post by **gtg737m** » 19 Mar 2006, 17:24

I have a 1994 850 Turbo wagon and I need to replace the rotors. Does anyone know of a website where I can find pictures and an explanation on how to replace the front and rear rotors? Is this a simple job for someone who has never done this? I appreciate a lot any help that I can get to do this. Thanks.

Post by **pfeener** » 19 Mar 2006, 17:53

Yes, this is one of the best DIY jobs. I'm sure there's pics of it out there someplace, but you don't see it so much because it's pretty basic. If you look through this repair section and the repair section on volvospeed.com, you'll get a good idea of how it's done. I suggest using Brembo rotors from FCPgroton. Good basis rotors for about $50 ea. I also like the genuine Volvo pads. Dusty little devils, but quiet.

Here's the steps: (I'm assuming you're going to change the pads as well)

remove tire
remove the spring clip on the caliper
remove the caliper (7MM hex socket required; remove the caps & the 7MM hex bolts that hold the caliper)
wire the caliper up to the strut spring to keep it out of the way
remove the strut mounting bracket
remove the locating pin/bolt holding the rotor
remove the rotor (you may have to spray the center with PB Blaster and give it a few love taps)
clean the new rotor throughly with brake cleaner
install the new rotor
remove the old pads
loosen the brake bleeder and compress the caliper piston (it's important to use the brake bleeder so you don't force the old fluid back through the ABS unit)
coat the back of the pads with brake grease (special grease - not regular grease)
reinstall the mounting bracket, pads, caliper and spring clip
flush the old brake fluid with new dot 4+

gtg737m · Post by **gtg737m** » 20 Mar 2006, 11:32

If I'm replacing just the rotors and not the pads, do I have to worry about bleeding the brakes? Do I have to make any adjustments even if while I'm changing the rottors I don't push on the brakes? Is it just a matter of setting the brake caliper aside without touching the pads and them putting it back after putting the new rotor?

Post by **matthew1** » 20 Mar 2006, 14:08

You don't have to bleed the brakes for pads, or rotors, or both. Pull the calipers out of the way with one of those lock-ties (large). Then cut it when you're re-assembling/done.

Post by **pfeener** » 20 Mar 2006, 18:51

I would strongly recommend changing out the pads while you have it apart, but if you decide not to change them; no adjustment of the caliper is necessary. Because the new rotors will be a little fatter than the rotors you remove (because of wear on the old rotor) you will need to compress the caliper piston slightly in order to get them over the new rotor. A large "C" clamp will do the job nicely.

Brake bleeding is not required when you service the brakes, whether you do just the rotors or the pads as well, but brake fluid absorbs moisture over time and if left in the system too long will promote rust within the brake lines and components, so it is typically recommended to flush the system with new brake fluid every couple of years.

Post by **pfeener** » 20 Mar 2006, 18:55

One more thing; make sure you do NOT push on the brake pedal while you have the calipers off the rotors. You will push the caliper piston right out of it's bore and brake fluid will explode all over the place as well as caliper parts.

utvol1984 · Post by **utvol1984** » 13 Apr 2006, 07:12

It's usually not a good idea to replace rotors without also replacing your pads. If your pads have any wear at all on them, they could wear your rotors un-evenly and possibly cause squeaks etc. Brake pads are cheap and you have it apart anyway, might as well do the job right. Good luck.

Post by **polskamafia mjl** » 18 Aug 2009, 01:48

Whats this brake grease stuff? Is it called brake grease at a parts store? And how much/where do you put it on? Also, once I put the new pads on do I have to readjust the calipers?

Post by **Zimbo** » 18 Aug 2009, 03:57

Yes you can buy brake grease at an auto parts store.

Put some on between the shim (If you're installing shims) and the back of the brake pad and I put a very thin film where metal to metal contact exists. You shouldn't have to readjust your calipers but with new pads you will need to fully compress the cylinder on the caliper so it will fit back over your rotors.

Post by **wheelsup** » 18 Aug 2009, 07:32

Just so you feel better, replacing the pads/rotors on my 850 was the first mechanical job I ever did outside of replacing the air filter on any car. It took a while but I didn't break anything. It's very intuitive. I would do one side first and leave the other mostly untouched so you can figure how to get it back together.

The Haynes manual for our 850's is actually very useful for our cars. I'd pick one up.