I had the system flushed and bled and check and things working fine now they are soft again, no signs of leaking, any ideas, is my master cylinder going out, father in law mentioned that there might be a brake line close to exhaust and getting hot and effecting the proformance of the brake fluid, all help welcomed.

thanks in advance

Larry

Could be the master, but the most likely culprit would be the rotors.

If the rotors are a bit warped, they will actually "pump" air into the brake system while you drive. The pistons in the calipers are held against the rotors by springs behind the pistons. When the rotors push the pistons in on the high spots, the springs push them back out on the low spots. This is when they can suck air into the system past the seals. As you drive along, you now have up to four very small compressors!

If a master replacement doesn't solve the problem, you may need to have the rotors resurfaced.

Larry,

If you know a machinist or someone with a dial indicator you could check the rotors for warpage like Joel said. As a precaution pull each wheel and check your calipers for leaks. Also check your brake hoses while your at it. I know you said it does not look like you are loosing fluid but it never hurts to be sure.

Take care!

I had the same problem that Joel describes with my rear rotors. Once I got them turned, problem went away.
The manual says they should be less than .005" TIR. Mine were about .010-.013". Have them checked or do it yourself.