Sounds like air in the brake lines to me. As you use the brakes, heat is
generated in the system, and in turn, the air expands as if you were
applying the brake. Try a thorough bleeding of the system in the proper
sequence and I think you may solve the problem. Just a thought - did you
bench bleed the master cylinder when you rebuilt it?
72 Spitfire - FK38809U
----- Original Message -----
From: Aidan Corcoran <email@example.com>
To: Spitfire List <firstname.lastname@example.org>
Sent: Wednesday, August 25, 1999 5:26 AM
Subject: Brake Problem
> A few weeks back I installed a new seal kit on the brake master cylinder.
> only got to drive about a mile, and things were ok. Last weekend, I took
> car out for a longer run, about 20 miles, and had the following problem.
> The brake pedal would get harder and harder to press down, and the front
> brakes in particular were starting to stay closed, and the engine would be
> fighting against the brakes bring always applied. Short term I resolved
> problem by unscrewing the brake line from the master cylinder a little,
> reducing the pressure in the brake system. Getting back home, I
> the master cylinder, cleaned it, and re-assembled it. The same problem
> remains, with the pressure in the brake system growing as I use the brakes
> until I'm forced to stop, and release it through the connection between
> master cylinder and the brake line. I have bled the system, possibly not
> very well, but this didn't change things.
> Have you guys any ideas?
> Thanks in advance,
> 1966 Spitfire Mk 2 (FC83365)