I would appreciate any tips on how to successfully mount the secondary cup on the piston of master cylinder. I am replacing seals on the original master cylinder and my aging arthritic fingers can't seem to gently or otherwise "slip" the secondary cup over the piston crown to get it into place. The manual says use of tools ist verboten! as you will damage cup etc. I guess he "rebuild" of bike is going to take quite a long time if stuck on this rather simple step. Cheers, John
Tip needed mounting secondary cup on piston master cylinder
- Thread starter ve3lz
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Re: Tip needed mounting secondary cup on piston master cylin
John, cover it in brake fluid before trying. 13 mm. is the real way to go.
John, cover it in brake fluid before trying. 13 mm. is the real way to go.
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Re: Tip needed mounting secondary cup on piston master cylin
Ugh its a tough task even w/o finger issues. I did one this summer and found it easier to force it over the lever side and work down to the groove. Might put the seal in hot water to soften it up some. Its pretty tough so un-edged tool can be used to lever it over lips. I may have used a hook with sharpe point to drag mine on then just slipped hook out, but don't tell I ignored the manual, again. I've two Combats and both developed leaks at the big outer boot seal so watch in don't drip on paint.
I solved it last time by Hylomar smear on center and rim edges of the boot. Took twice to stay dry over 1000 miles - so far so good this last couple 1000.
Ugh its a tough task even w/o finger issues. I did one this summer and found it easier to force it over the lever side and work down to the groove. Might put the seal in hot water to soften it up some. Its pretty tough so un-edged tool can be used to lever it over lips. I may have used a hook with sharpe point to drag mine on then just slipped hook out, but don't tell I ignored the manual, again. I've two Combats and both developed leaks at the big outer boot seal so watch in don't drip on paint.
I solved it last time by Hylomar smear on center and rim edges of the boot. Took twice to stay dry over 1000 miles - so far so good this last couple 1000.
Brooking 850
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Re: Tip needed mounting secondary cup on piston master cylin
As Steve says, yes you can use a scriber or similar, to be on the safe side, get a brazing (gas welding) rod and peen the end with a hammer on the back of your vice,into the shape you require, being softer metal, it wont damage the cup if you have to use a bit of force and slip off. I use the same for O rings. Lead the cup on the piston, put the tool under and roll around until it goes over. Put the piston in the vice using 'soft jaws' to keep a grip!!!!
If you decide to use an upgrade as in 13mm, ie (RGM)I have just done mine and have pics and hints to help if need be.
Regards Mike
As Steve says, yes you can use a scriber or similar, to be on the safe side, get a brazing (gas welding) rod and peen the end with a hammer on the back of your vice,into the shape you require, being softer metal, it wont damage the cup if you have to use a bit of force and slip off. I use the same for O rings. Lead the cup on the piston, put the tool under and roll around until it goes over. Put the piston in the vice using 'soft jaws' to keep a grip!!!!
If you decide to use an upgrade as in 13mm, ie (RGM)I have just done mine and have pics and hints to help if need be.
Regards Mike
Re: Tip needed mounting secondary cup on piston master cylin
Thanks to all the suggestions, item is installed with no apparent? damage. I will probably upgrade to 13 mm size piston eventually. I am running a 12 inch disc with AP caliper from Norman Hyde, obtained 20 years ago. It was better than standard disc suet up but would probably be even better with upgraded master cylinder. Many thanks, Tschuss, John
Thanks to all the suggestions, item is installed with no apparent? damage. I will probably upgrade to 13 mm size piston eventually. I am running a 12 inch disc with AP caliper from Norman Hyde, obtained 20 years ago. It was better than standard disc suet up but would probably be even better with upgraded master cylinder. Many thanks, Tschuss, John
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Re: Tip needed mounting secondary cup on piston master cylin
If ya take a orange-red hot 6 penny nail run through the stupid tiny restrictor hole to completely remove any restriction you can get most if not all of what a 13 mm neck down cylinder provides right now on the cheap. None of the resleeves have any restricition so its safe and now after experiencing both back to back I feel that's there main reason everyone likes them over stock restristed ones. After feeling the significant difference i think restrictor put in for law suits of drum brake pilots going over the bars too often.
If ya take a orange-red hot 6 penny nail run through the stupid tiny restrictor hole to completely remove any restriction you can get most if not all of what a 13 mm neck down cylinder provides right now on the cheap. None of the resleeves have any restricition so its safe and now after experiencing both back to back I feel that's there main reason everyone likes them over stock restristed ones. After feeling the significant difference i think restrictor put in for law suits of drum brake pilots going over the bars too often.
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