Author Topic: Help me with a master cylinder rebuild!  (Read 10639 times)

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Offline nobody

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Re: Help me with a master cylinder rebuild!
« Reply #25 on: July 19, 2009, 04:07:48 PM »
Anybody? Somebody here has to have an answer. I've read at least seven or eight threads on this topic and I can't find an answer.
74 cb750k

If life hands you lemons, make lemonade. If life hands you tomatoes, make tomato soup. If life hands you a box of hand grenades... well, now... THAT'S a message!!

Offline BeSeeingYou

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Re: Help me with a master cylinder rebuild!
« Reply #26 on: July 19, 2009, 04:32:03 PM »
The check valve seems to have been discontinued after 76? or not used on some models at all.  If it leaked at the boot either your cup is in backward , damaged or the cylinder bore is gouged.

Offline nobody

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Re: Help me with a master cylinder rebuild!
« Reply #27 on: July 19, 2009, 04:48:37 PM »
Which way does the cup go in? I had it to where the open end was over the top of the spring, is that right? I'm pretty sure there isn't a hole in it as I was very careful with it. I doubt the bore is gouged, the roughest thing I put in there was a red scotch bright to clean out some of the old hardened deposits on the bore walls.
74 cb750k

If life hands you lemons, make lemonade. If life hands you tomatoes, make tomato soup. If life hands you a box of hand grenades... well, now... THAT'S a message!!

Offline BeSeeingYou

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Re: Help me with a master cylinder rebuild!
« Reply #28 on: July 19, 2009, 06:58:24 PM »
I would guess the cup on the piston is the problem.  It does sound like you had the other cup in correctly.  Are these the old parts or did you put in a rebuild kit?  Mine leaked at the same spot after it's long storage but not as bad as yours seemed to so I put in a rebuild kit and no problems now.  If you get the kit get the OEM Honda kit and not the cheap generic e-bay ones.  The difference is only about $10.00.

Offline nobody

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Re: Help me with a master cylinder rebuild!
« Reply #29 on: July 19, 2009, 08:07:49 PM »
The guts are new and oem honda parts. I went out there a little after dinner and put it back together. The fluid doesn't seem to be coming out of the back anymore, the boot wasn't swelling and I couldn't see noticeable traces of fluid when I removed the boot to check. There is fluid coming out of the output hole but it's kind of a dribble. What kind of pressure should I be seeing? Should it be trickling out like it is or should I be seeing a glorious fountain of brake fluid?
74 cb750k

If life hands you lemons, make lemonade. If life hands you tomatoes, make tomato soup. If life hands you a box of hand grenades... well, now... THAT'S a message!!

Offline BeSeeingYou

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Re: Help me with a master cylinder rebuild!
« Reply #30 on: July 19, 2009, 08:24:50 PM »
I never tried pumping mine without any hoses attached but keeping in mind the relatively small volume of the cylinder it can't be too much of a "glorious fountain of brake fluid". ;D  There also may be air in the unit and it would be difficult to bleed as it is basically open so it may not pump properly until hooked up and bled.