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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => Project Custom Motobricks => Topic started by: erictyler11 on October 10, 2016, 12:28:34 PM

Title: Grease for rear master cylinder?
Post by: erictyler11 on October 10, 2016, 12:28:34 PM
Is there any particular grease you folks would recommend using for the rear master brake cylinder? I took the boot off last night and whatever was there was granular, yet it was not from outside elements. The repair manual states to use ball bearing grease for any locations not mentioned, and this seems to be one of them. - Eric
Title: Re: Grease for rear master cylinder?
Post by: Martin on October 10, 2016, 04:34:21 PM
I use heavy thick silicone grease under the boot, it's the same grease I use on the fluid coupling steering damper.
Regards Martin.
Title: Re: Grease for rear master cylinder?
Post by: Inge K. on October 10, 2016, 06:15:42 PM
Is there any particular grease you folks would recommend using for the rear master brake cylinder?

Search "red rubber grease".


I took the boot off last night and whatever was there was granular, yet it was not from outside elements.

That is crystalized brake fluid, you have a small leak in that brake cylinder.


The repair manual states to use ball bearing grease for any locations not mentioned, and this seems to be one of them.

Never ever use petroleum based products in the brake system, it destroys the gaskets.
Title: Re: Grease for rear master cylinder?
Post by: gazman on October 10, 2016, 08:45:09 PM
1+ Rubber grease
Title: Re: Grease for rear master cylinder?
Post by: erictyler11 on October 11, 2016, 05:11:00 PM
Thanks for your advice  :clap: Is the brake fluid leak from the master cylinder something to be concerned about, or should I continue to ride until  the fluid continuously oozes? :mbird
Title: Re: Grease for rear master cylinder?
Post by: Laitch on October 11, 2016, 06:37:58 PM
Thanks for your advice  :clap: Is the brake fluid leak from the master cylinder something to be concerned about, or should I continue to ride until  the fluid continuously oozes? :mbird
Fix it so you'll have a rear brake when you need it.
Title: Re: Grease for rear master cylinder?
Post by: Inge K. on October 11, 2016, 07:11:25 PM
Check the if the gaskets isn't worn and check the bore for corrosion.

Sometime it's enough with a good clean out and a reaming of the bore, very fine emery paper
and a screwdriver handle can also be used this.
Very caryfully clean out the bore afterwards with methylated spirit to it's absolutly clean,use red
rubber grease on the piston and gaskets when remounting.

Check for leaks now and then as a routine the next couple of weeks when in use.
Title: Re: Grease for rear master cylinder?
Post by: stokester on October 11, 2016, 08:17:50 PM
Never ever use petroleum based products in the brake system, it destroys the gaskets.

Great advice.

Any petroleum-base product in the braking hydraulic system will cause the seals and boots to swell and deteriorate.  That is why only brake fluid is used for internal caliper components and silicone-based lubricants on the slide-pins for your car.