Rear brake master cylinder

[Dewclaw34]

I have an '83 FT 500 with a seized master cylinder. Tried the usual heat and penetrating oil to no avail. Any suggestions welcome

[greenjeans]

heat.  Usually if they are frozen, the internals are pitted and generally not useable.   I'm trying to find out which master cylinders  (off another bike) might be compatible with the old one.

[murdo]

As an experiment I drilled a 1/4" hole in the end of an old seized master cylinder so I could put a punch through and knock out the piston. That sucker was so tight that after many big hammer hits I had succeeded in swelling the alloy piston so much that it split the cylinder wall, and the piston was still stuck. 
If you cannot get it out with air pressure or a grease gun then you are best to look for a new one.

[Dewclaw34]

Thanks guys I will look for a replacement unit

[Dewclaw34]

Fitted a 2000 CBR600 unit. Needed to swap reservoir and feed pipe to suit new dimensions. MOT passed today - happy days

[murdo]

Good work.

[hangon]

Hi all!
New here. Rebuilding a rust pile found outside a car mechanics...
Had almost the same problem, Cracked the caliper trying to get the seized air vent screw out...
So, the cbr 600 brake - although not looking the same - not being a double piston brake, fits fine except the issue w cables and reservoir?
Are there other rear brakes that might fit?

Thanks!

Oh, sorry! Found the info needed in this superb forum:)
At least I realize that there is a difference between master cylinder and caliper.
Tech english is not my best. Living in sweden.
I will probably check in later with more questions and hopefully some answers too.


/pat

[patrino]

I'm running a 2007 EX250 (250 Ninja) rear master cylinder on my FT500.  I made an adaptor with a piece of 1/4" aluminum plate:  cut out a parallelogrammy shape, drilled four holes, and mounted it up.  The master cylinder mounts to two of the holes, the other two fasten the adaptor to the threaded tabs on the frame (which held the OEM master cylinder).

$20 for the master cylinder and $10 for the aluminum, plus a couple hours of time.  Maybe more work than you're willing to do, but it's working well on my bike!