Replacing master cylinders or MC seals

[daverclasper]

Hi. Just an idea. If replacing brake (or clutch) MC unit/seals, could it be bled from the top (say overnight, etc), by wedging the pedal down and loosening the top cover, so the air at the top of system bleeds out (saving cost of more new fluid and time).

Thanks Dave

Edited December 26, 2019 by daverclasper

[Guest]

Hello Dave,

Not really. You really do need to push the fluid through the lines to ensure any air bubbles are dislodged and expelled from the system.

On completion of doing this and you are happy with the pedal, I then lock down the pedal for about 12hrs as this ensures any minute air bubbles are dislodged and escape to the top. It does make a big difference and firms up an already good pedal after bleeding.

As such you are correct in thinking about the idea, but it is not suitable to fully bleed the system, only to get rid of the last minute air bubbles.

Hope that assists ??

Best wishes.

Richard.

[Pete Lewis]

short cuts   you win or loose,  i have only once changed a full cup Mcyl seal on a simca 1501 i had , you could upturn the seal  in the bore

flip it over under fluid and refit the circlip without removing the pipes or re bleeding,  it had a crass design that the recoup hole wore a groove in the seal 

every time it passed over it.

never tried on any others as the vitees has a full piston to remove , a short cut is not going to work ...unless ?????

Pete