6 replies to this topic

[Verderad]

How do you get the Master cylinder pressure differential piston out?
I have a black tag master cylinder I can’t work out how to remove it.
Haynes manual doesn’t suggest any special technique

I’ve removed the switch. Cleaned out the crud behind it. I can see the piston through failure switch hole.

I’ve tried a bit of pressure into switch with a foot pump.

[Verderad]

Problem solved.
Lots of penetrating spray in top and switch hole
Tap tap with small persuader to punch it in, lever it up through hole
Stand and read Bens latest thread.
Pulls out with pliers.

[MiniMadRacer]

I am wondering why, unless its just curiosity, I assume the master cylinder is foo barred, and you will be buying a new one

[Verderad]

No it’s perfectly serviceable.
Removed the piston. Cleaned, put on new o rings

[MiniMadRacer]

Excellent, I am no longer brave enough to do that, always now go for a replacement, I have never successfully rebuilt a master or slave cylinder, but I did try when skint back in the 80s, but bore rust always defeated me in the end

[Spider]

When stripping these cylinders, I found removing the Reservoir and then the screwed Plug over the Differential Valve, then using air in the lower port should get the shuttle out. If it doesn't using shop air, may as well bin the valve at this point because it'll be rusted in. If the valve comes out, then continue removing the main Pistons etc.

The issue with these is the part of the Differential Valve where the Switch screws in is vented to the atmosphere and so they usually rust in that chamber, between the O Rings.

[bpirie1000]

I usually lubricate and then some compressed air in there. But issues arrise when there is any corrosion on the inner..

Either way if it works.... it works..

Well done..