I previously posted a thread on my brake problem.

In a nutshell, when driving it the brakes progressively lock themselves after approximately one or two miles of driving. Initially when starting out, no brake issues. After a while, you can hear a pad gently rubbing against a rotor. It slowly gets progressively worse until the brakes stop the car.

One member of the forum suggested it could be a brake line that has deteriorated on the inside which would not allow the brake fluid to retract easily. This make sense.

I also did some more research on brake systems in general and on a couple of US car forums people mentioned that defective brake boosters could do the same thing. Could this also be the possible problem in my Jaguar? Also, once the brakes are locked up, could I disconnect the vacuum line from the brake booster and see if this releases the brake pads?

Any other ideas on how to troubleshoot?

What I would like to do is figure out a systematic way to troubleshoot this rather than blindly start replacing parts which could end up being expensive.

thank you

As the brakes get warm, the fluid expands. Normally there is enough airspace on top of the fluid in the master cylinder to compensate. If the master is overfilled, what you describe may occur.

It is my understanding that an automotive brake system is not a closed system at the master cylinder.

Sorry I didn't read the last thread but have you considered that the caliper pistons may be sticking? Have you done a full fluid flush and refill?

Pressure in the master cylinder would just cause it to leak, IMHO.
RagJag

If your brake lines haven't been replaced at the front wheels, by all means, it can't hurt. I bought the front lines for about 19.00 each. And clean fluid in these cars seems to be the best thing you can do for them, as the fluid absorbs moisture over time, works against you. Water expands with heat, so if the fluid has absorbed moisture, this "could" be your problem.