Help - MH Brakes Locked Up!

[swebster]

Dennis (87MH) is having some trouble on the road. Just got off the phone with him and he asked me to post this message seeking answers to some issues he had with his MH brakes locking up on the trip from Texas to Georgia (he did make it to the campground finally).

Here is the background:

• 1987 345 MH
• Recently replaced the rear brake discs, calipers, shoes along with new flexible lines and a new master cylinder (read about it here)

Here is the issue:

• Rear brakes gradually locked up to the point where the MH could not longer move. He "unlocked" them by releasing line pressure from the rear caliper bleed valves.
• Next time the problem occured it was with the fronts - fixed it the same way
• It continued to happen on the fronts over and over again.
• He avoided hard braking and supplemented braking with the Toad brakes and the MH parking brake but he mentioned that the issue did not seem to coincide with actually using the service brakes on the MH. In other words - if he never touched the brakes at all they would eventually lock up

His questions are:

• What could be causing this?
• Is there a simple mechanical solution?
• Is this related to the master cylinder?
• Should he just replace the master cylinder with a a GM Factory cylinder?

I'll be calling him back this evening so any and all ideas and suggestions would be appreciated. I'll also (as many of us) be seeing him this weekend so we can bring parts and tools if necessary - but knowing Dennis he won't want to wait until then