Author Topic: Brake master cylinder rebuild help.  (Read 626 times)

Online bigbikerrick

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Brake master cylinder rebuild help.
« on: June 08, 2023, 11:23:16 AM »
Hello Folks, The rear master cylinder on my Convert has a small drip, of fluid. This will be my first time taking apart/rebuilding a master cylinder. I have ordered the rebuild kit from MG Cycles. Is there any good tutorial/instructionsl on how to do it? Any tips anyone would like to share, on pitfalls to avoid, etc...
Thanks in advance,
Rick. D.
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Offline guzzisteve

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Re: Brake master cylinder rebuild help.
« Reply #1 on: June 08, 2023, 11:49:20 AM »
It's covered pretty well in the G5/Sp1000 manual. I'm analog though.
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Online bigbikerrick

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Re: Brake master cylinder rebuild help.
« Reply #2 on: June 08, 2023, 02:41:47 PM »
Thank you Steve, I will check that  manual out. Dont feel bad....I am "analog" also, Sir! :laugh:
Rick
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Offline guzzisteve

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Re: Brake master cylinder rebuild help.
« Reply #3 on: June 08, 2023, 03:53:29 PM »
Hey, I actually use paper bound manuals up to 05.
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Re: Brake master cylinder rebuild help.
« Reply #3 on: June 08, 2023, 03:53:29 PM »

Online bigbikerrick

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Re: Brake master cylinder rebuild help.
« Reply #4 on: June 08, 2023, 05:35:10 PM »






Well, I got the master cyl. off and taken apart. Removing the piston was a bit of a bugger, it took a bit of "persuasion" with a small punch and hammer.  I found a you tube video, for rebuilding the MC on a Ducati darmah, which was helpful, as the two are similar. The workshop manual, like Steve suggested was also helpful.
Below is a link to the helpful video, in case anyone is interested.
https://www.youtube.com/watch?v=8OQz4f5MS9U

Rick.
« Last Edit: June 08, 2023, 05:37:25 PM by bigbikerrick »
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Offline guzzisteve

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Re: Brake master cylinder rebuild help.
« Reply #5 on: June 08, 2023, 07:57:14 PM »
You'll be using that hammer again to put the locking washer in place.
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Online n3303j

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Re: Brake master cylinder rebuild help.
« Reply #6 on: June 08, 2023, 10:04:51 PM »
Make sure the bore is not pitted before installing the new rubber parts.

I've also seen it recommended that one replace that cap and float with a sealing cap and rubber bellows to keep moisture out of the brake fluid.
'98 MG V11 EV
'96 URAL SPORTSMAN
'77 MG 850T3 FB

Online bigbikerrick

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Re: Brake master cylinder rebuild help.
« Reply #7 on: June 09, 2023, 12:14:56 PM »
Thanks ,Gentlemen, for the suggestions.much appreciated.
Rick D.
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Offline guzzisteve

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Re: Brake master cylinder rebuild help.
« Reply #8 on: June 09, 2023, 02:19:39 PM »
It helps if you push piston in when you are putting in the cupped seal & lockring washer(also cupped). I push in w/screwdriver down the center of a 13mm or size that fits, then hit end of the deepwell socket home. That way you are not pushing in the piston w/socket and seal can get all the way home w/o interference.
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Online bigbikerrick

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Re: Brake master cylinder rebuild help.
« Reply #9 on: June 10, 2023, 12:05:18 PM »
Thank you very much, Steve. That makes sense. This is a fine example,of the kind of "hands on" advice I was looking for. Its the little details like that, which make a big difference in the final outcome, and help us ham fisted mechanics, keep these cool old bikes on the road. I will be receiving my rebuild kit soon, and feel confident, that ,with all the sage advice received here, it all goes smoothly. :thumb:
Rick D.
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Offline guzzisteve

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Re: Brake master cylinder rebuild help.
« Reply #10 on: June 10, 2023, 01:01:55 PM »
You need 3 hands for it or a holder like a vice.
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Online bigbikerrick

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Re: Brake master cylinder rebuild help.
« Reply #11 on: June 11, 2023, 03:16:59 PM »
Ok, I think I will use a little 4" vice I have to hold the master cylinder body, while I work on re assembly. Good tip!
Rick.
"You meet the most interesting people on a Guzzi"

 

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