Removing brake pistons?

[Fallout]

I have a good lever from just bleeding the callipers but I'll remember that trick just in case.

Interestingly what got me curious was a dude on YouTube was bleeding his MC via a nipple, but it was on a trail bike. I'm guessing this is because they generally need more maintenance and the MC is likely to take knocks and end up on it's side a lot which may introduce bubbles.

[Sid Squid]

Originally Posted by Runako

Stuff

If you do it right you don't need to bleed the master cylinder - that's why there's no bleed there.

Originally Posted by Sid Squid

If you do it right you don't need to bleed the master cylinder - that's why there's no bleed there.

I suppose if I could have got you down to sunny wales to do it for me, it would have been easier

Originally Posted by Fallout

Interestingly what got me curious was a dude on YouTube was bleeding his MC via a nipple, but it was on a trail bike. I'm guessing this is because they generally need more maintenance and the MC is likely to take knocks and end up on it's side a lot which may introduce bubbles.

I'm guessing its just a more modern design of master cylinder to make the process easier but I don't know for sure. From what I can see, the more modern/expensive bikes tend to have a bleed nipple on the MC.

When I fitted the new caliper assembly yesterday afternoon, it literally took me less than ten minutes, to put the replacement caliper on, refil a completely drained brake system and bleed it. I found the old caliper to be the reason I couldnt gain pressure again.

Originally Posted by JonGeorge

When I fitted the new caliper assembly yesterday afternoon, it literally took me less than ten minutes, to put the replacement caliper on, refil a completely drained brake system and bleed it. I found the old caliper to be the reason I couldnt gain pressure again.

Do you know why the caliper caused that? It might be good to know in case someone else has the problem of seized pistons.

This is what I can't work out, it wasn't a fluke either as I tried re-gaining pressure for 2/3 hours with the old caliper back on and the pistons pushed in (Not that the stuck one ever moved anyway. Its a mystery, I think maybe the seal had gone completely on the piston which came out, hence holding little pressure ...

pump them out with a grease gun,never had a piston i couldn't get out,even if they are rusted in solid

Originally Posted by JonGeorge

Ok, went and got some brake fluid, used the hydraulics on the bike and only 1 piston came out? What nhow

What you need to do is hook both back up to the bike and then find something solid to put into each brake calliper.

If you find something that is thick enough so the pistons can extend most of the way but not drop out, then when you pump the brakes both sets of pistons will extend almost all of the way and stop at the same point. Then remove whatever you were blocking them with, keep pumping and some of them will come out, and whichever ones are left will be easy to remove with a pair of pliers because they will be 90% of the way out already.