ok, So I bought some new rotors(Brembo), and new Genuine Volvo Pads from FCPGroton. I bought the front sets only, my plan was to intially just change the front pads and rotors. So I started with the front right tire, I popped off the tire and got it jacked up on stands, I got off the caliper off, and the pads were off. The rotor seemed to be stuck on it was pretty rusted. So I hammered that off. Then I put on the new Brembo rotor, I put on alignment pin.
So then I tried to compress the piston so it recedes back into the piston housing. Didn't seem to work no matter what leverage I used, So I went to my local auto store and bought one of those tools for compressing the piston. It's like a lead screw, and a plate that pushes it in. I used that, and pushed it in several millimeters. Then I tried to put the caliper around the new rotor and pads, and there wasn't enough room. It was too short by about 1 or 2 millimeters. I tried to compress the pad more, and I used some channel locks to turn this device more, and the stupid plastic handle broke off. Damn manufacturer saved 50 cents and I suffer for it, they could have used metal, but used plastic instead. So I tried to wrap channel locks around the lead screw, but the caliper piston seemed to be compressed as much as possible. O yea, I opened the container under the hood for the brake fluid, so there was no resistance. But the rubber boot around the piston ring on the caliper, was broken. I was thinking maybe some particle got inside there, or something. I dunno.

So I'm not really sure what my question is. Should I get a new brake caliper/piston? Or should I get a better tool for compressing the piston in the caliper? Anyone experienced this before?

Any help is much appreciated, Regards, John


then I put on the glue on the back of the pads, and the grease where the pads mount to the caliper.

 

Welcome to the club.

Next time you buy a tool, I would look on the label on the back of the package to see where it's made, and if it's made in C.... I would spend extra to get made in the USA orJapan.

The piston area was probably corroded and if any part of the piston/caliper is damaged, I would consider a rebuilt caliper on both sides. See what Tech says on this. In general, you would have enough clearance to put the pads once the piston is pushed far enough. I used a 10WR locking plier (Vise-Grip) and didn't use anything else to push the piston.

I would put either silicone-based or molybdenum-based brake lubricant on all metal-to-metal contact surfaces EXCEPT the friction surfaces of course. Generic brake quiet compound won't do for the 850s. I used cv-joint grease, which is moly-based, and the squeak from the rears was gone forever. Generally, you can stop the rear squeak by installing half-size shims but mine kept squeaking even with the half-shims.


JPN

 

Definitely get new/rebuilt calipers. A torn piston boot means leaks and also the possibility of trash getting into the piston bore itself.

 

You're probably done already, but I have always found that if I can't push the piston as far as I need with a pair of channel locks, a new caliper is needed. Be sure to tighten all of the bolts when you are done. I got interrupted by a phone call while finishing up recently and failed to do so. I lost a bolt and had a hell of a time getting a replacement.