front brake caliper piston is stuck

[steve vu]

82 suzuki GS650L, the front brake caliper piston is stuck. Am not sure when was the last time anyone touched it. I have tried using the compressor to force it out, did not work. I soaked it WD-40 and it is still stuck. Any suggestions?

[Nessism]

More air pressure. Just make sure you use a rag as protection for when the piston shoots out.

If you don't have more air, I've heard of people using the brake master to pump brake fluid into the caliper until the piston poped out, and some people use grease from a grease gun as well but I don't recommend this method because the grease is a pain to clean.

Good luck.

[hampshirehog]

If you don't mind boogering the seals a bit of heat on the alloy can help as well. Otherwise both Ed's suggestions work 99.9% of the time.

Absolute last resort - drill a hole in the caliper and punch the piston out. You then have to get the alloy welded up or tap a thread in to it and stick in a bolt. I've done it once and it worked but that was the mother of all corroded calipers.

[rustybronco]

The long slow and hard way...
pack the banjo bolt hole with grease and screw a bolt with the same thread into it, remove the bolt, add more grease, thread bolt into the hole again.
repeat as necessary.

the faster way...
put a bolt with the same thread into the banjo bolt hole, loosen the bleeder screw and put a grease gun on the bleeder.
then pump away.

works for me when they're really stuck.

[nisom512]

I just rebuilt 5 calipers on my bikes and I useded the keeping it attached to the line and pumping a ton of brake fluid in there that is the safest and cleanest and cheapest and easyest way IMO