5 ton brake booster help

[vtdeucedriver]

Hey all. I got a stranded M52A2 since july at a friends house 50 mi away. I had a smoking right rear and right middle axle. I got her there to his house with a very stiff pedal.

I took. it as a bad brake booster because when I was at the rally, i had the smoking right rear and i drained out about a 1/2 qt of water on the air side. This was my 1st big run of the year and with the truck after its restoration.
My question is, could i still have a bad master cylinder???? I put the airpack in today and I plan on getting the truck tomorrow. I got really good brake pedal and she stops fine sofar..........i am just worried about locking brakes again.

 

[BEASTMASTER]

coud be yes, the last parade i was in my brakes started dragging and would'nt release .took the master cyl. apert and cleaned it , and put it back together ,no problems since .

 

[acetomatoco]

Jeff, you probably should bleed the whole system before you contaminate the new booster with crappy fluid... and make sure the push rod is adjusted with the correct amount of play in the MC...

 

[5tonpuller]

Drain every time I park it.
Also add some oil to that little GD hole in the back of the booster. ( I want to KILL the guy that put the death grip on that little plug )
I was told by the mech. at the armory that was one of the most common things for brake hang ups.
my $0.05 worth.
Matt

 

[acetomatoco]

Jeff already had the OHT lecture from me at the VT show..

 

[BKubu]

Bleed a little of the fluid out at one of the wheels. This will release the brakes and will allow you to get home. I've had this problem before. Apparently, the brake pedal needs more play. I bet your brake lights were stuck on when you pulled over. This is because the expansion of the brake fluid (when it got hot) activated the brakes. Just as ACE says, it is the push rod going into the master cylinder that needs to be adjusted.

 

[vtdeucedriver]

ok let me ad this. I drove the truck home when i bought it and she drove from NH to vt for 5 hrs without problems. I have not touched the brakes since then until now with the airpack R&R. you still think the master needs to be adjusted??? I will ask the guy that was behind me. but he never mentioned that my brake lights came on.


what is the correct amount of adjustment for the MC??

 

[acetomatoco]

Not necessarily the problem, Jeff, we are diagnosing from a distance and these are valid points... M800 series truck had the same problem on route to the Stowe Show one year...and I opened a bleeder and proceded home with no brakes to speak of...the master push rod is just one cause...your airpak full of water was another and who knows what is in your master if you have not flushed it yet.. I would not put on a new air pak without flushing all the fluid out of the system...and put that OHT in the new booster before you put it on the truck...is easier on the bench....I am still not convinced that the one brake you had dragging was a mechanical event and not a hydraulic event...have you pulled that wheel or at least backed off the brake adjustments or exercised the return springs for that wheel??? And yes, you should not have sold the Andy Truck....amen...

 

[vtdeucedriver]

ok here is a question...........if its mechanical, why would the brake pedal get stiff like it did??

 

[vtdeucedriver]

BTW, did flush the master, drained it fully but the booster is installed now......................if it were mechanical, what would cause the stiff pedal???