Brake issue

[TominMO]

Drove the Festy a couple of days ago and noticed the brake pedal was feeling a little mushy. Today when driving it, the pedal slowly goes all the way to the floor. If I pump it, I get full braking for a second, before it starts going to the floor again.

I checked the brake fluid reservoir; it is full and clean. Haven't gotten under it to check for leaks, but I would think that a leak, letting air in, would also let fluid out, but the reservoir is full.

I would prefer to not suddenly lose all braking (not my kind of excitement), and solicit your thoughts.

[Team Lightning]

Sounds like the master cylinder is bypassing to me. Lack of low fluid condition tells me its not a leak, but the mc is not holding pressure, therefore, the bypassing comment.

[TominMO]

Sounds like the master cylinder is bypassing to me. Lack of low fluid condition tells me its not a leak, but the mc is not holding pressure, therefore, the bypassing comment.

I did wonder if it might be the MC, but not sure how that would work. How would it be bypassed when pushing the brake pedal, since the pedal linkage is connected to the MC pushrod?

[Team Lightning]

I'm thinking bad seals/o-rings inside the MC

[TominMO]

I'm thinking bad seals/o-rings inside the MC

Thanks. Could well be. I think this is the original MC, so 28 years old! I think I have a spare one around to swap in, but if not I'll go buy one. Meanwhile I'll garage it for the remainder of the winter.