More Brake Questions

[CharlieB]

So I have replaced all of the brake hoses front and rear and have bled the system. Calipers have also been cleaned up and rebuilt.
After bleeding the brakes I went on a quick test ride (5 miles or so) and the brakes seemed to be working ok. A little soft but fully fumctional.
An hour or so later I was going on another ride but this time the brake pedal was very firm at first and then rock hard after about a mile. The brakes were still working but I didn't want to risk it so I turned around and came back home.
Is this a sign of a failing brake booster? Or am I missing something else?

[vandor]

Was it just firm, or also difficult to push? If so, then it could be the booster (check the booster hose).
Were the wheels warm? Almost sounds like they might be slightly dragging. If so, you may need to shorten the pushrod that is between the booster and the master cylinder.

[CharlieB]

Thanks Vandor, yeah I'll try that. I assume I have to remove the master cylinder to get to it...correct?

[CharlieB]

Sorry Vandor I forgot to answer your other questions.
The pedal was very difficult to press, not just firm. I was able to push the car easily, so the brakes are not dragging. If it ever stops raining, I'll go for another trip around the neighborhood.
Thanks for the help

[vandor]

If they were not dragging then it is not the pushrod. Sounds like the booster is not working. Check that the hose is not collapsed. Some people use heater hose instead of booster hose and it collapses after a while from the vacuum.