OKay so I just got done installing new wheel studs and wheel bearings on the front end of my 240. Also doing a brake job on the front. Now I have a piston that refuses to budge on the passenger side. Other three pistons on that side went back in like butter but that fourth one is stuck. I'm at wits end...again. First it was the rear brakes, then I had to replace the rear wheel studs with the brakes, then the front brakes and wheel bearings go, then the FRONT wheel studs, and now after I just got done doing the bearings and studs THIS happens.

Is there any way to unstick it without removing the caliper from the car? I have a knack for breaking bleeder screws so I REALLY don't want to remove the caliper because I don't have enough money to buy two new calipers (since you never replace just one side) when I break a bleeder.

 

If the piston is stuck it means that most likely moisture has infiltrated in there and rusted. Only real solution is to pull it out and rebuild it. Or easier yet, just spring for a set of rebuilt calipers. My '90 has the same problem and I have just ordered a set of front calipers. I suspect the ones on there are original.

 

Ouch, breaking bleeder screws. Maybe not so much torque on these. Snug... plus works well.
When I replace pads, I always open the bleed screw and use a C clamp to depress the pistons. That allows the hottest, most used brake fluid to be flushed out. After a few more cycles when bled, I feel I've rotated out much of the older line fluid.
I would never depress the calipers with the bleed screw tight and force the old fluid back up into the system.
It also might help from allowing that moisture to build up as noted above.

 

Do you live in a "rust area"? I can see that being a problem there.

Soak those bleeder valves in PB Blaster or similar before starting the job and then use a six point socket to get them off. Still, if they too rusty you'd have to use heat.

If you need another caliper and are short of funds, may be you can get a used one; and replacing them in pairs is, well, desirable but not crucial... As long as they are not frozen, that's all that counts... You can try Craiglist or even Ebay, besides a junk yard. Plenty of old Volvo parts on the market...

 

OKay so in my small spare parts reservoir I found a set of brand new rear caliper boots and piston seals. Can I use those to rebuild the front passenger side caliper? They look as though they fit fine and the set is only short one piston seal (no idea where that fourth one went).

And yes. I live in a VERY rust prone area. Western PA. My calipers look like they're original to the car when, in fact, they are only two years old. It didn't help that the people who did the reman didn't paint the calipers with any sort of protective measures. Also yes, I have to do things the cheap way. No necessarily the right way.

 

Well, try and rebuild them then! Especially since you have the parts. This rust belt is a bitch--I can always tell: a couple of winters in snow and everything is corroded. I don't even see how you can keep an older car going with so much rust...

 

I only have enough to do the caliper that is froze up. The car itself isn't rusty much at all. A few small spots on the undersides of the doors and one bad spot on the body right behind the rear passenger door. That spot is because previous owner smacked something and improperly covered up the dent with putty. I removed the putty and now I just spray on some rust converter once a year. In another two years it'll rust through. Then I'll putty it and drive it until the engine blows up or that spot gets bad enough to render the car structurally unsafe.

 

I don't think the rear boots will fit on the front. You will also need new seals. Go over to Rock Auto and take a look at what they offer as far as rebuild kits and do it up right. Kits start at less than $3.00 and will do one caliper.

 

make sure you get seals for the right type of caliber too... volvo often used 2-3 different brake calibers on the same year/model car, depending on what was available.

 

I have both rebuilt calipers, bought rebuilt calipers and even found a new replacement caliper at one point. With so many pistons and so much moisture it seems I am working on a frozen piston once a year. I feel for you. You can rebuild them, be careful and use Nutblaster or Kroil and heat if needed as Lev said. The tough part is getting the frozen piston out. If you have the time, remove the seal and spray the piston with some penetrating oil and let the piston sit overnight.

Use compressed air to try to remove the piston. Place a piece of wood so that when the piston gets launched out, it hits the wood. If this doesn't free it up, try pushing it in with a clamp. Be careful not to **** it. Once it is moving try to get it out with air again.

Once the piston is removed, clean up the bore. You are supposed to use a hone. I have used Scotchbright and it worked out well.

Good luck. Let us know how it goes.