TR2/3/3A caliper piston stuck

[tomnanney]

Anyone have a good way to free a stuck caliper piston? The caliper is off the car. One came out easily with compressed air , but the other one won't budge!
Thanks
tom

 

[Geo Hahn]

If you reinsert the removed piston and clamp in place you should be able to apply some serious pressure to the opposite side. Some possible source of the pressure:

Air -- easiest but possibly least effective.

Hydraulics -- reconnecting to the car's brake line and using the pedal, a lot of pressure but may be impractical if much of the rest of the system has been removed or is non-op.

Grease Gun -- never had to resort to this myself but some have adapted a grease gun fitting to the caliper inlet and pumped grease forcing the piston out. Messy but at this point that is possibly not a concern.

Whatever you do - keep fingers and other parts out of the way.

 

[trglory]

Having one out gives you the extra room you need. Press the stuck caliper back in with a C-clamp and a socket. If it is cocked, press first at the high point.

Joe

 

[Darrell_Walker]

I saw this on the Moss Motoring blog recently:

https://www.mossmotoring.com/frozen-brake-caliper/

Pretty slick idea, basically block of the hydraulic connection on the caliper, fill with fluid, then use a clamp to press the free piston in, which will force the stuck piston out.

 

[mrv8q]

Grease gun worked fine for me. As Geo says, messy, but effective!

 

[sail]

A bicycle foot pump got mine with the other piston held in the caliper by a board and 2 C clamps to the workbench.
Not messy but to clamp it on the bleed valve had to cut the end of the hose off.

 

[tomnanney]

A bicycle foot pump got mine with the other piston held in the caliper by a board and 2 C clamps to the workbench.
Not messy but to clamp it on the bleed valve had to cut the end of the hose off.

thank for all the posts. I put the other piston back in and clamped it down. Used compressed air and the other one came out! Now the rebuild starts!
tom

 

[sp53]

If I remember correct, I took one of those zerk fittings offthe lower wishbone because the threads are not cut on a taper like most zerkfittings and somehow hillbillyed that on a grease gun then plugged the other side with a piston and itcame right out.

 

[dklawson]

I saw this on the Moss Motoring blog recently:
https://www.mossmotoring.com/frozen-brake-caliper/
Pretty slick idea, basically block of the hydraulic connection on the caliper, fill with fluid, then use a clamp to press the free piston in, which will force the stuck piston out.

I REALLY like that idea. I have known people to use the grease gun method before but that seems like it would need an awful lot of chemical cleaning later. Closing the caliper off and using the trapped brake fluid sounds so much neater. However, I hope I don't have to try this anytime soon!

 

[alanjohnturner]

Zerk is a new word for me. In the UK these are "nipples".

Just thought you would all like to know that.

 

[Geo Hahn]

Oscar Ulysses Zerk

 

[TomMull]

Zerk is a new word for me. In the UK these are "nipples".

Just thought you would all like to know that.

Oscar Zerk's fame has not spread to the UK? (I had to look this up): https://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=21910566

 

[dklawson]

What a neat bit of history! Thanks for posting it!