Freeing frozen piston in master cylinder

[stovebolt]

Any suggestions on how to free a piston in my master cylinder. It is the piston at the bottom of the bore. I've soaked it with WD40, blasted it with compressed air, tried hooking it with a piece of wire, all to no avail. Any suggestions would be appreciated. Thanks, Joe.

[Mike S]

 Did you remove the retention screw from the floor on the inside?
Mike

[stovebolt]

Yes, I did remove the stop screw.

[maroman]

Can you MAKE a grease fitting to fit into a hose fitting? Block the others and pump it full of grease.

[stovebolt]

Thanks, I will try that.

[stovebolt]

I made an adaptor by turning a metal rod to a squeeze fit in a brake line fitting then drilled and tapped it to accept a standard zirk grease fitting. After blocking off the three holes at the bottom of the reservoir with a piece of hard rubber and a C-clamp, I pumped in grease with my standard pistol-grip grease gun and out it came.
Thanks for the suggestion.

[maroman]

Cool beans, glad it worked for you. I'm thinking a standard grease gun produces something like 1200 PSI, multiply that times the area of the piston and that's how much pressure you have. The grease is cheap to fill the cavity and can be reused.

[69Z28-RS]

Has anyone bought a Master Cylinder Rebuild kit recently?    Any suggestions on source for one?

[tmodel66]

I know I keep beating the NAPA "Drum" but they either had all this stuff or could get it over night. I used Wagner and Bendix brake stuff. The good thing about NAPA (well my NAPA guy) he tells me if it's import or not and can get the good stuff  (made in USA)  95% of the time.