Brake Caliper Piston is FROZEN!! How do I remove?

I've tried the 'ol blow air into the inlet to no avail. It is a two piston caliper so I'm trying to get them out together. I've soaked them in penetrating oil, used extra fine sand paper on the exposed part of the piston then sunk it with a c-clamp. I really don't want to convert to a single piston caliper so if anyone knows of a way I'm not trying then please let me know. I know there is a kit I can order for mucho $$$$$$$$$$!!! Thanks in advance.

I just read something about a method a guy used to push out his stuck caliper piston. I just browsed the article but he used a grease gun to force the piston out. Something was said about the grease was thicker and he could get more pressure from the gun? Like I said I only glanced at the article but maybe you can get an idea from it.

Later, Doug

Thanks bro. That's a good thought. Although, the thought of cleaning out thick grease is enough to make me think twice. I have an extra master cylinder from a car and I'm thinking of rigging the caliper to the MC and stomping on the plunger. What if I used a torch to heat up the pistons?

Alabaster wrote:

Thanks bro. That's a good thought. Although, the thought of cleaning out thick grease is enough to make me think twice. I have an extra master cylinder from a car and I'm thinking of rigging the caliper to the MC and stomping on the plunger. What if I used a torch to heat up the pistons?

If using heat, thinking would be better to heat the area around the pistons.

Also heard of filling caliper with water, plugging the inlet, and putting the caliper in the freezer overnight.
[You already know the rest of this story -- and the risk involved].

Good Luck!

I had the same issue on my bike. I used a grease gun to pop the pistons out. I wasted a good amount of grease doing it, but I didn't want to freeze the caliper with water.

Grease doesn't compress like air and it has to go somewhere. This causes the piston to pop out.

As far as cleaning it wasn't bad at all. Used the good ole finger to wipe the grease out and q-tips. Then used some good degreaser, then alcohol, then rinsed it with brake fluid. Replaced the seals, slaped her back together and it works great.

The trick part was getting the grease gun to connect to the caliper. I was lazy so I used a bolt to screw into the banjo bolt hole and then used the bleeder nipple to attach the grease gun (it was a PITA to detach the grease gun later). I suggest finding a grease gun fitting that will screw into the bleeder hole.