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Master Cylinder piston won't come out.

  • Thread starter Thread starter ThomasTedder
  • Start date Start date
T

ThomasTedder

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I'm trying to get the master cylinder apart to rebuild it, but I can't get the piston out. I've soaked it in PB Blaster for about two days now. I've even tried using compressed air. Still won't budge. Yes the circlip is out. Any ideas?
 
ThomasTedder said:
I'm trying to get the master cylinder apart to rebuild it, but I can't get the piston out. I've soaked it in PB Blaster for about two days now. I've even tried using compressed air. Still won't budge. Yes the circlip is out. Any ideas?
Click to expand...

Have you tried a little heat on the body? If not I think I would put it in a small can with PB and put that can in a small pan with some water in it on a stove and cook it a while. Ray
 
Since you're going to rebuild it anyway drop it in a can of Berrymans.
The heat idea sound good too.
 
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Its probably just stuck from years of neglect. Use the PB blaster and let it soak. I've removed one from an 850L that was pretty stuck. Try this.. put the brake lever on the mc body with the bolt but reverse it so the hook part of the lever catches the lip on the mc piston. Basically it works like a pry bar. Work it back and forth to raise the piston. Don't go crazy and put gorilla force on it cause you don't want to break the lever. I found this worked better than a pair of pliers because it was hard to get the pliers into the well around the piston. Hope this makes sense.
 
Can't do the PB in the house. My wife swears we're all gonna die from cancer every time she thinks she smells a fume.

I was considering the Berrymans. In a few more days, after the carbs are done soaking I'll try this if it's still stuck.

almarconi, I'm trying to imagine in my head how to use my lever as a .....lever. Could you please explain this a little better?
 
please do i am having the same problem with one of my bikes.....:D
 
I would get another master cylinder. Once you get it out you may find the bore is not serviceable anymore.
 
Try some heat and maybe a needle nose vise grips. Are you going to buy a rebuild kit for the mc. If the piston is toast you can try putting a rod in through wear the banjo bolt threads into and driving the piston out.
 
I would get another master cylinder. Once you get it out you may find the bore is not serviceable anymore.
Click to expand...

That is another option. I'd work on it a little longer and see what it looks like inside.
 
almarconi said:
If the piston is toast you can try putting a rod in through wear the banjo bolt threads into and driving the piston out.
Click to expand...

This is what I did and it worked great, just got the brakes rebuilt and all seems well and good.
 
almarconi said:
Try some heat and maybe a needle nose vise grips. Are you going to buy a rebuild kit for the mc. If the piston is toast you can try putting a rod in through wear the banjo bolt threads into and driving the piston out.
Click to expand...

I've done that in the past, but I don't think the design of this m/c will allow that. The bolt hole is on the bottom and the piston is on the side. Could you describe a little more please, if I'm misunderstanding you.
 
If you do get it apart use a shotgun cleaning brush to remove rust from the entrance. I find it is the perfect sized tool for the job and the brass won't scratch the harder steel.
 
I was able to fit it in with one of the carbs in the Berryman's. I'll try again after it has a good soak.

duaneage said:
If you do get it apart use a shotgun cleaning brush to remove rust from the entrance. I find it is the perfect sized tool for the job and the brass won't scratch the harder steel.
Click to expand...

Good idea. I happen to have more guns than most of people on this forum have motorcycles. Finding a bore brush will be easy.
 
I hope you have both circlips out. One is for the rubber boot dust cover, that comes out easy. Then there's a snap ring underneath it. On mine, I just used a set of needle nose vice gribs to clamp onto the piston. I just yanked it out hard.
 
I've done that in the past, but I don't think the design of this m/c will allow that. The bolt hole is on the bottom and the piston is on the side. Could you describe a little more please, if I'm misunderstanding you.
Click to expand...

My comments were geared towards the L style master cylinder. After looking at the parts fiche for the G model this would not work.

I would try to soak the part, apply heat and continue to try and move the piston. Eventually it will come out.
 
Tarbash 27 said:
I hope you have both circlips out. One is for the rubber boot dust cover, that comes out easy. Then there's a snap ring underneath it. On mine, I just used a set of needle nose vice gribs to clamp onto the piston. I just yanked it out hard.
Click to expand...

Well if there's a second circlip in there, that could explain things. I looked, but maybe it's hiding under some rust.
 
Well if there's a second circlip in there, that could explain things. I looked, but maybe it's hiding under some rust
Click to expand...

What did the clip you removed look like?

The one that holds the boot on is a piece of wire shaped like a half circle



The one that hold the piston on looks similar to this..
 
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To remove the snap ring you need a pair of snap ring pliers with very long jaws or a machinists scribe. I used a scribe because I had one and didn't want to spend the money on the pliers.
 
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