Author Topic: Brembo master cylinder rebuild  (Read 10741 times)

Offline Dellortoman

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Re: Brembo master cylinder rebuild
« Reply #15 on: July 12, 2020, 01:37 »
That bloody mud in the hydraulic fluid is a bit of a mystery to me. I dunno where it comes from, but it seems to contaminate all hydraulic systems after a few years. Brake and clutch hydraulic systems are closed, so I very much doubt it's dust that gets in from outside. It doesn't appear to be metallic so it's not from cylinder wear. It must be some chemical change in the fluid that causes particles to precipitate.  Are there any clever people out there who know the answer?
Location: Tasmania, Approx 4253S 14723E

Online Laverdalothar

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Re: Brembo master cylinder rebuild
« Reply #16 on: July 12, 2020, 10:12 »
I suppose it is a mixture of water and wear. The piston f.e. has a coating, maybe that wears off a bit and builds up that mud together with some water (Any time you open the reservoir to top-up the fluid, it comes in contact with air and might drag some humidity out of the air into the system)
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1000 SFC 1985 #2934 currently under restoration
1000 SFC Preproduction bike 1985 #0001 *sold*
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Online Laverdalothar

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Re: Brembo master cylinder rebuild
« Reply #17 on: July 12, 2020, 10:15 »
Lothar,
It was mud. A couple of sessions in the ultrasonic cleaner loosened it up nicely. Thanks.
Ian

 (cheers)

great it worked out to be just mud and now you can re-assemble the sucker again. Be careful after re-building it, make sure it really holds together and is tight and sealed correctly. Better test the brake with slowly riding several times and check the fluid reservoir stays full.
750 SF(0) 1971 #9934 *sold*
1000 SFC Classic 1989 #3367 *sold*
1000 SFC 1985 #2934 currently under restoration
1000 SFC Preproduction bike 1985 #0001 *sold*
1200 Jota 1981 #7474
750 S-Formula 2000 #1602
1000 Motoplast - currently under construction

Offline CLEMTOG

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Re: Brembo master cylinder rebuild
« Reply #18 on: July 12, 2020, 10:18 »
surely its the degradation of the black seals?

I notice on TOG that the fluid is nice and clear in the (see through Ducati) master cylinders, but that it changes to dark then black over about three years, by which time the fluid should be changed anyway., Seals maybe after six years, leaking or not, we all do that don't we?
CLEM

Offline Mactriple

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Re: Brembo master cylinder rebuild
« Reply #19 on: July 13, 2020, 09:06 »
(cheers)

great it worked out to be just mud and now you can re-assemble the sucker again. Be careful after re-building it, make sure it really holds together and is tight and sealed correctly. Better test the brake with slowly riding several times and check the fluid reservoir stays full.

I will get the parts re-anodised and go from there. is the o-ring a special one?
ian

Online Laverdalothar

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Re: Brembo master cylinder rebuild
« Reply #20 on: July 13, 2020, 10:01 »
I don't think they are made of a special material, but they are special shaped. So - no chance to have them replaced by something "standard". You will always need to replace the complete piston set. But then - how often do you do that...? Every 30 years is a good interval I would say...  ;)
750 SF(0) 1971 #9934 *sold*
1000 SFC Classic 1989 #3367 *sold*
1000 SFC 1985 #2934 currently under restoration
1000 SFC Preproduction bike 1985 #0001 *sold*
1200 Jota 1981 #7474
750 S-Formula 2000 #1602
1000 Motoplast - currently under construction

Offline Andre

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Re: Brembo master cylinder rebuild
« Reply #21 on: September 03, 2020, 08:46 »
The guide was very helpful thanks Lothar. Made it simple.

Andre

Offline Mactriple

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Re: Brembo master cylinder rebuild
« Reply #22 on: September 12, 2020, 06:11 »
Thanks Lothar the instructions were very helpful. Just finished both M/Cs from the 860cc MV Agusta Monza. Worked out very well thanks. The most expensive part was getting both bores re-sleeved due to corrosion. Cheers
Ian

Online Laverdalothar

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Re: Brembo master cylinder rebuild
« Reply #23 on: September 20, 2020, 07:21 »
great it was of help, thanks for the feedback
750 SF(0) 1971 #9934 *sold*
1000 SFC Classic 1989 #3367 *sold*
1000 SFC 1985 #2934 currently under restoration
1000 SFC Preproduction bike 1985 #0001 *sold*
1200 Jota 1981 #7474
750 S-Formula 2000 #1602
1000 Motoplast - currently under construction