Brake pedal doesn't come back up, brakes lock up

[jleo313]

Hey guys I am new to the forum and new to being an RV owner.  I have an 87 Itasca Windcruiser with brake problems.  The brake pedal depresses but doesn't wanna come back up.  The brakes seem to be locking up and getting hot...Any suggestions?

Thanks and glad to be a part of this community.

Jarrod

[DonD]

Welcome..

I've read that the Hydroboost is not user serviceable other than adding p.s. fluid and bleeding the system. Have you checked the p.s. fluid level?

Has any work been recently done on the brake system?

[jleo313]

I took it to a mechanic and the brakes were locked up.  He turned the rotors, new calipers, new pads, bled the brakes and filled with p/s fluid.

The only thing now that it is not doing is the brake pedal still lacks bouncing back all the way about an inch.

[DonD]

http://www.scribd.com/doc/6829161/Operation-Diagnosis-and-Repair-of-HYDROBOOST
I recently replaced my hydroboost unit myself, wasn't too bad. Much better brakes.
Good luck with your issue, I'll be watching....

[tiinytina]

A new hydroboost unit is pretty cheap... easy to replace.... ours was boiling the fluid one trip out... eeeks.. we did whole brake system when that happened as well... one rear caliper was locked from it... 

Tina

[jleo313]

So far so good....no more issues.  How would I know if the hydroboost was not functioning properly?  Would my brakes fail to work, or would they just not work as well?

[DonD]

Mine had no boost so took lots of effort to stop.

[shimmy]

Do you know if this is on the front brakes?

I had a similar problem.  The cause was the flex hoses between the frame and the caliper.  There was a kink or weak spot in the flex line. 

I understand that the high pressure from the hydroboost will force pressure to the calipers but normal pressure won't allow the hydraulic fluid to go back into the master cylinder.  The lines can be purchased at Advanced or Auto Zone for about $20 each.  Replacing them and bleeding the lines got me back in business.

[Lash61]

If the above fails to remedy the situation check the proportioning valve, Mine was stuck from sitting so long  and as a result would not back off so the fluid could travel back up the line . So my callipers were seizing to one front rotor. Luckily mine was serviceable. By the way I had done all of the above.