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Re: 'frozen' brake cylinders

To: mgs <mgs@autox.team.net>, mgt <mg-t@autox.team.net>
Subject: Re: 'frozen' brake cylinders
From: Bullwinkle <yd3@nvc.net>
Date: Wed, 04 Oct 2000 21:08:06 -0700
Listers:

This is a little long, so if you don't like long threads delete.

Blake

***********************************
Parts of this message were taken from a thread in another BBS
        
Todd Gray, Canton, OH , USA, toddtts@nls.net 

Just Getting into rebuild of the MC on my 1600. Clutch side working OK but will
rebuild anyway. The piston in the brake side is stuck, jammed all the way to
rear of the MC. Any advise on how to get this piston out? I cannot get the MC
cover off (the screws are rusted on and stripped). 


Steve Merical, Illinois, USA, merical@aol.com 

If it's not stuck too bad you might be able to blow through were the brake line
attaches and force it out (worked for me). Air compressor should work too - just
be careful as the parts will fly out 


Ben Baldock, staffordshire UK, bjbaldock@hotmail.com 

  Todd, I have also had the same problem as you, I tried heating the MC and then
inserted a hand drill With a bit slightly smaller than the diameter of the
recess in the piston into the MC so it located in the recess of the Piston by
turning the drill slowly it freed of the piston however beware of any fluid left
in the MC as
this WILL boil when heated, I found out... By the way once you have managed to
free the piston it is worth having the MC re-sleeved, If you change all your
braking system at the same time you may want to use silicone fluid (see archives
for posts on silicone fluid) hope this is of help Ben 


Randy Myers, Santa Rosa, CA, Dovecon@msn.com 

Todd,

I had a similar problem with the piston in my slave cylinder and used the air
compressor idea with great sucess. I had the slave cylinder on the bench,
wrapped in a towel, and kept pouring wd-40 down the cylinder and periodically
tapping (gently)the piston and casing of the slave cylinder to break it loose.
After a couple of days of soaking and rewrapping the slave cylinder then
applying air pressure at the pipe connection hole it broke loose and came flying
out like a bullet- the towel caught it and saved it from damage to itself and
me.

Good Luck.

Randy Myers 


Todd Gray, Canton, OH , USA, toddtts@nls.net 

Thanks for the advice guys. I am going to try the air compressor idea tonight. 
Randy I have put so much WD-40 on this thing I think it might be flammable for
the next decade. Randy did you have to hone your cylinders after you got the MC
piston un-stuck?  Ben did you use a propane torch on the MC? Thanks again guys. 


Blake J., in SD 

Take a used brake line fitting and add a grease zerk to it. Use the grease gun
to expell the stuck piston. Alot safer than compressed air and builds up much
higher pressure. 



Les Bengtson, Arizona, USA, ragnar@aztec.asu.edu 

  Blake. That is a great idea. Like Randy, I
  have had the "bullet" parts when using com-
  pressed air. Todd. I have given up on using
  brake hones. Instead, I use a flap sander
  with 320 grit cloth to very lightly go over
  the interior of the cylinder. This will show
  any corrosion or roughness which would re-
  quire sleeving or boring the cylinder for an
  oversize seal kit. To make a flap sander,
  use a piece of 1/4" rod, about 6" long and
  cut a slit about 7/8" deep along the center
  axis on one end. Chuck the un-slotted end
  into a drill or die grinder and put a strip
  of 320 grit into the slot. You need drill
  rod for the die grinder, but cold rolled will
  work with a drill. The key word is "light"
  polish. Keep it moving and just remove the
  crud. Clean with brake fluid. Les 



Todd Gray, Canton,OH USA, toddtts@nls.net 

  Blake... What Size is the grease fitting you were using ?? I have tried the
"air thing" it did not work. On to the grease idea.
  Thanks to all 


Blake J. in SD 

  Todd:

  I can't find the one I made. The zerks I still have measure 1/4" or 0.25". The
brake pipe measures 0.20, so you may have to drill, and tap?, the fitting. I
believe I may have soft soldered the two parts together, too. 


ben baldock, Staffordshire, United Kingdom, bjbaldock@hotmail 

Todd, I have just tried Blake's grease method on another two seized master
cylinders that I had lying around, Wish I had known about this method when I
tackled the first one! The pistons came out with no problem and the MC is now on
its way to be re-sleeved. 


Todd Gray, Canton, OH , USA, toddtts@nls.net 

Thanks again to all for advise. The zerks idea indeed works great. I just sort
of rigged something up in the fitting department.  MC is rebuilt and back in the
car and working great!! Onto the next project!

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