Stuck pistons

[the red baron]

Hi Guys, I've got the old locked up front brake problem on my 73 TX650, i took the caliper apart today after reading a thread about the same issue, however my caliper dosn't have the floating design, it appears that only the pistons move, how do i get them out ?

Cheers

 

[I am Carbon]

Air will usually do it but the trick is you have to break the stuck piston loose 1st. Put a big C-clamp on it and press it in a bit. Not much, it won't go much, just enough to break it free. Then put the air to it, it'll move out a little bit, then squeeze back in with the C-clamp, then air again ...... repeat, repeat, repeat. It will come out a bit more each time and eventually pop - and I mean POP. Put a large balled up rag under it and keep your fingers out of the way.

 

[the red baron]

Thanks, just the air gun from compressor into hole fluid line would usually screw into

 

[I am Carbon]

Thanks, just the air gun from compressor into hole fluid line would usually screw into

Yeppers

 

[gggGary]

bolt caliper back together backwards kind of make it look like a butterfly. Do what carbon suggests with the c-clamp. Heat doesn't hurt let it sit with a hair dryer pointed at it for 10 minutes. put a c-clamp loosely over BOTH pistons. you want both loose, near the end of travel before you let either one all the way out. If they are fighting you, alternate air and c-clamp moving them in and out slightly if needed. Final desperation method is a zerk and grease gun in the line fitting. Once apart decide if you can clean up and reuse the pistons (rust pitting) or need to replace or buy a whole new caliper.

 

[5twins]

Once one piston pops, you're going to lose all your air pressure for getting the other out. I bolt the caliper halves back together with a small square of sheet aluminum between them covering the fluid crossover hole. This effectively isolates the two halves. Blow air in the line hole on one and the bleed nipple hole on the other. I just use a tapered rubber fitting on my blow gun, pressed hard into the hole.

 

[Wingedwheel]

I'm working on Bobbing a '72 and the caliper had been sitting for 13yrs or so. I split the caliper and worked the bleeder side piston in and out with a clamp and air until it finally "popped". I took a small piece of aluminum, drilled two holes in it to fit the pattern for the hex bolts. I then just put a small piece of old inner tube rubber underneath, used a couple of large nuts for spacers and hand tightened it down. It sealed the fluid hole just fine and the hose side went easier than I expected. The hardest part of the job was keeping the small o-ring from twisting. lol

 

[the red baron]

I'm working on Bobbing a '72 and the caliper had been sitting for 13yrs or so. I split the caliper and worked the bleeder side piston in and out with a clamp and air until it finally "popped". I took a small piece of aluminum, drilled two holes in it to fit the pattern for the hex bolts. I then just put a small piece of old inner tube rubber underneath, used a couple of large nuts for spacers and hand tightened it down.View attachment 57794 It sealed the fluid hole just fine and the hose side went easier than I expected. The hardest part of the job was keeping the small o-ring from twisting. lol

Thanks i was trying to figure how to solve that problem

 

[jonesey]

Just as 5Twins and W W explained, but if they are really stuck u might have to resort to pumping them out with a grease gun. i did some about a year ago and when i saw grease come out of the one i held it in a vice until the other came out. A little more messy than air but somtimes u need a little more omph.

 

[Wingedwheel]

I tried the grease route first and they were stuck too badly. The back and forth method worked much better for me

 

[jonesey]

Yes, i guess a lot depends on what u have at hand, i'm pretty sure the back and forth method will work well. Once u got movment your half way there. a little penetrating oil would also help once its moving. i'm sure my grease pump can out perform my wanked out old compressor so out they came. Either way is good.

 

[peanut]

I got mine out by using a pair of stilsons and gland pliers . I just gripped and turned whilst pulling the pistons out at the same time . It took a while as they were very rusty.
You are going to replace them anyway so it doesn't matter if you chew them up.

 

[Wingedwheel]

Peanut, mine were actually in pretty good shape, no pits or rust. Once i got them out I cleaned them with some 4x steel wool and they were shiny and beautiful.

 

[peanut]

excellent
although skinflint that I am I don't think I would be tempted to save money reusing 35+ year old brake pistons myself . They are surprisngly cheap

 

[ROYSTON]

You can put some water in there, close off the holes & put the calliper on a camping stove in the yard, that shifts them, does set off a few car alarms in the street, though.

 

[the red baron]

Thanks Royston, that sounds like me i may just try that, after all bikes are all about fun

 

[happydaze]

excellent
although skinflint that I am I don't think I would be tempted to save money reusing 35+ year old brake pistons myself . They are surprisngly cheap

Where do you buy them?

 

[peanut]

Where do you buy them?

Yambits in England

 

[650Skull]

32 English pound may not be much to you Peanut but if i could get them out without damage and they were good, pistons don't wear out unless they are rusty. i would be spending the money saved on new Brake lines.

 

[Wingedwheel]

Mine were incredibly clean even after being stuck for years, I did replace the lines which were actually the only rusted part of the system and the rebuilt calipers work awesome!