Master cylinder leak <-> front right blocking at the track ?

[asylum]

I encountered braking poblems today at the track. I could only use half of the breaking power I used to apply because my front right wheel always blocked when trying to brake harder. I though it could be a problem with the brake power repartitor (I have a '92). At the lunch pause, I checked the master cylinder and saw it was leaking (see below). The pedal feel was ok. Fortnaltely it was just a small leak and it did not brake at the end of a straight.

Do you think my blocking wheel problem can be linked to this master cylinder leak ?
Else, what should I check ?

 

[illwillem]

I assume by 'blocking' you mean 'locking'? when the wheel was locking was the ABS coming on too or was the wheel just locking up without the ABS kicking on. A guess would be you have something blocking one of the proportioning ports in the master cylinder. Regardless Id take care of the leak and flush all the fluids.
I would unplug the ABS and see i it still happens you could then rule that out or narrow it down as a problem. Goodluck

 

[silver2002]

Open question: Does the paint bubbling suggest it has been leaking for a while?

 

[asylum]

It is possible that it leaks for some weeks as it is a track only car and it was my first track event of the season. I flushed the brakes last month to prepare for the track season. It is true I did not feel the ABS acting. The wheel locks and I realy have to release the pressure on the pedal if I want to stop the locking.

I plan to replace the master cylinder and flush the ABS.

 

[asylum]

Problem solved. I replaced the master cylinder. Then I made the ABS bleeding procedure by activating the solenoïds one after the other. One of them did not want to open. I had to activate it at east 20 times till the fluid began to flow through.