brake master cylinder

[Avanti7]

I have brake fluid leaking from the master cylinder at the connection point to the booster. Is it possible for fluid to get onto the booster and if so will it ruin the booster?

[WayneC]

Yes, if the rear seals (O-rings) on the master cylinder piston leak, the fluid can be sucked into the booster and attack the bladder. If you are using silicone brake fluid, the booster bladder may not be damaged, but the master cylinder still needs to be repaired/replaced.

 

Edited December 31, 2019 by WayneC
add'l info

[scottgriggs]

I agree with WayneC.  I have had this happen on a brand X vehicle and became aware of it because of a hissing noise when actuating the brakes.  The fluid leaking into the booster created an audible vacuum leak.

 

Scott Griggs

Louisville, KY