Brake Problem

[eagle19952]

OK this is not my MH, but a fellow who has a 1966 Travco built on a Dodge M375 chassis is having a few problems, the major one, the newest one, is as described below.
My guess is the master cylinder or the vacuum booster....but it's to many years since I messed with anything but air brakes. So trying to help a roaming family with two little kids, brakes would be handy.
Here's what he says.

After a stop today I started up the Travco and went to drive away only to find the brakes were locked up. So locked up the bus wouldn't move. After a few minutes they loosened up, but then they were super soft and we had almost no stopping power. They worked a bit if I pumped them a couple times. We limped into a truck repair shop and bled the four brakes. I drove around the block, but there was no change. Super soft and needed to be pumped. We all scratched our heads, then took off the wheel that had just been worked on in Amarillo. Everything looked okay there. Then the mechanic and I rolled underneath to look at the brake booster and noticed another bleed valve on there. We bled that one and boom, the brakes felt like new again. I drove around the parking lot, all good. We left, drove through town about two miles to an RV park. I went inside to pay with the engine running, came back out and the brakes were locked up again. Shut down the engine. Waited a couple of minutes and they loosened up, but were soft and hardly working again. Limped into our spot and called it a night. Long day.
My only thought is that since I drove around the parking lot between bleeding the four brakes and the time we bled the booster that maybe there is still air in the system. I need to bleed the whole thing at one shot. Of course it could be something more, master cylinder, or booster? I don't know.
Any ideas?

[luvrbus]

Find the filter and clean or replace it should be on the frame rail past the drivers seat it has probably never been change since the 70's and some had dual Hydro/Vac systems one for the front wheels the other for the rear wheels

good luck

[Jim Eh.]

Maybe they should try a complete brake fluid flush. Brake fluid has a nasty habit of absorbing moisture. Really a wise thing to do each spring on a vehicle that puts a big demand on their hydraulic brake system.

[chessie4905]

   Were all the wheels locked up, or just front or rears? If both, probably needs new master cylinder. If just front or rear, needs that hydrovac replaced. Opening the bleeder released the pressure in system that check valves should have done when foot was removed from pedals.

[oldmansax]

What Clifford said....

TOM