Frustrating air pack

[m37dsl]

So long story short i installed all new brakes on my deuce and cannot get the air pack to function properly. Rebuilt all 6 wheel cylinders, all new rubber lines, rebuilt master cylinder, installed kit in air pack and honed bores slightly.

Where i stand now is air being sent to the back side of the air chamber when no brakes are being applied causing them to drag. I took it apart last night and found the little exhaust valve sticking so i cleaned that up and now it is not quite seating all the way. The TM says to tighten the nylock nut on the exhaust valve inside the air pack until one thread is showing. If i tighten it a little bit further will it help it seal by creating greater spring tension? Has anybody else had problems with these rebuild kits?

-Is the newer style air pack worth upgrading to?

-Does anybody sell a gasket for the back of the air pack that actually fits and stays in one piece?

 

[Clay James]

Just got done doing the same to my brake system. TONS of work.

There's no rebuild kits for the new style air pack so if it breaks you have to buy a new one.

Would RTV work instead of the gasket? I've used it on lots of stuff on my trucks and it holds fine.

 

[gimpyrobb]

There's no rebuild kits for the new style air pack so if it breaks you have to buy a new one.

That is incorrect. I bought a rebuild kit from Monkeyboyarmy. Also, the new style has a better design and less parts to mess with when it needs rebuilt.

 

[Clay James]

That is incorrect. I bought a rebuild kit from Monkeyboyarmy. Also, the new style has a better design and less parts to mess with when it needs rebuilt.

I guess things have changed. I've always heard there weren't. Good thing since I have the new style in my A2.

 

[SoundGuy]

Mine did this and it turned out to be the master cylinder. It would apply pressure but not release it. I finally figured it out when I pumped the petal until it wouldn't move when stood on. I then released the air pressure using the gland hands and the pedal still wouldn't move.

 

[m37dsl]

When i let the air bleed out the brakes release.

 

[rlwm211]

I think you need to isolate the problem. What I mean is to make GD sure that it is the air pack and not the master.

Apply the brakes.
Then, release the input brake pressure at the bleeder on top of the air pack. If the brakes release then the pin hole relief port is plugged in the master. This is quite common when you hone the master cylinder. The port is tiny. less than 1/16.

An additional way to make sure the master is ok is as follows:

If you look inside the master with the cover off and apply the brakes by hand and then release you should see an upwelling in the master as the fluid returns to the master. If you do not then you have the problem with the relief port.

At www.jatonkam35s.com in the deuce tms there is a tm from Wagner Lockheed that has great cutaway drawings of the master and how this all is.

I will be honest and tell you that I have rebuilt a lot of air packs and I have yet to have an issue. Oh, I do tighten the nylock nut on that valve all the way which is how it is when you take it apart. The valve seat comes against a shoulder on the brass valve assembly anyways.

Check the master and make sure it is not the problem and let us know what you find.

RL

 

[gimpyrobb]

Yup, I forgot about that compensating port, make sure that is open before going further.

 

[Flyingvan911]

Check the little hole in the Master Cylinder that lets the fluid come back in to the MC. It may be plugged.

 

[salvorone@aol.com]

gimpyrobb is right , rebuild kits for the newer style shorter air packs are available , have installed a few from memphis equipt. and they work fine , 150.00 i think check your air discharge line , had a dirt dobber fill mine one time clogging up the works

 

[bugei]

m37,

are you familiar with this posting and thread?

http://www.steelsoldiers.com/deuce/7623-airpack-rebuild-warning.html

if you know about this error in the tm, then carry on, if not, it is worth being aware of. my truck did some really wierd stuff when i missed a step. gotta say, it is quite exciting when you have "full pedal" and no brakes on 13,000 pounds of moving metal. e-brake check . . .

 

[m37dsl]

m37,

are you familiar with this posting and thread?

http://www.steelsoldiers.com/deuce/7623-airpack-rebuild-warning.html

if you know about this error in the tm, then carry on, if not, it is worth being aware of. my truck did some really wierd stuff when i missed a step. gotta say, it is quite exciting when you have "full pedal" and no brakes on 13,000 pounds of moving metal. e-brake check . . .

Yes i double checked that seal last time it was apart.

 

[turnerman]

had the same problem it ended up being the compensation valve piston was to tight and not sealing. loosened it and until no threads showed on the shaft and then it worked great. if the spring is tight, bad, makes no sense to me but it worked. the tell tale sign is the air bleeds out the passenger rear air glad hand.

 

[m37dsl]

OK update i havent had a chance to work on the deuce in a while but checked it out tonight.

-Started out removing J pipe and with air system up to pressure and no pedal applied air is leaking to the J pipe and therefore to the back of the pack.

-Next i loosened the nut on the compensator valve as stated above and put it all back together... Lots more air leaking to back of airpack, worse than when i started..

-Tightened nut a little bit further than when i started (maybe 2 threads showing) and leak is almost gone.

-Tightened it almost all the way (2.5 threads showing) and air leak has stopped!

-Tested brakes and drove truck around everything works great i just have a very slight drag left after getting brakes hot.

-I dropped all the air out of the tanks and the drag remains which points me to a hydraulic return issue.

-I plan on cracking the bleeders at the wheels and at the booster to determine where the hydraulic return issue is.

-If no pressure exists behind either breather perhaps its just a matter of adjusting the shoes now?

 

[gimpyrobb]

Sounds correct. I would adjust the shoes anyway. An easy shortcut is .015 top and bottom.

 

[m37dsl]

UPDATE...

Took the truck out this weekend and after a couple of applications of the brakes they were dragging.

So i pulled over and cracked the bleeder on the airpack... Nothing

Cracked the bleeder on one of the rear wheel cylinders and the brakes released.

So that tells me the master cylinder is not the problem... Correct?

If i back the nut off on the compensator valve then air will leak into the back of the air pack causing the same problem?