Rebuilding a master cylinder - oring grease?.

[cheese]

Is there a specific grease to use? I have some molykote 111 grease, is this ok?

[schrodingers cat]

Is there a specific grease to use? I have some molykote 111 grease, is this ok?

Simply wet the o-ring in brake fluid. Or a bit of vaseline does no harm.

Really the point is to allow the seal to slide in first time and not fold or tear. Once there is fluid in the system all becomes moot

[vr4king]

Simply wet the o-ring in brake fluid. Or a bit of vaseline does no harm.

Really the point is to allow the seal to slide in first time and not fold or tear. Once there is fluid in the system all becomes moot

Rodger that

[cheese]

Thats what I thought, but I got told something slightly different I thought that the grease could gum things up??

[CookMySock]

Use only brake fluid inside it, and any sort of grease under the boot to reduce corrosion.

[KevinD]

Use only brake fluid inside it, and any sort of grease under the boot to reduce corrosion.

You can buy specialized rubber grease (Red Colour)specifically for brake pistons it keeps the pistons corrosion free and keeps the dust seals and piston seals supple.

[CookMySock]

You can buy specialized rubber grease (Red Colour)specifically for brake pistons it keeps the pistons corrosion free and keeps the dust seals and piston seals supple.

Yeah I know, but it washes out with the brake fluid anyway, and where there is brake fluid you wont get water and correspondingly you wont get corrosion.

Behind the boot where there is no brake fluid should be copiously gooped with any grease - doesnt need to be anything fancy.

[imdying]

You can buy specialized rubber grease (Red Colour)specifically for brake pistons it keeps the pistons corrosion free and keeps the dust seals and piston seals supple.

Sadly, it does not for any significant length of time. Basically it's an assembly lubricant. PL7S is still the best for that too (IMO, but I've tried a few).

If you're only doing the odd one once a year, brake fluid is all you need. When you're doing fifty a week a tub of red rubber grease is an economical way to go.