Brake Not Bleeding off Pressure

[WhoMe08721]

Hey Guys,

Went out today with one of my m35a2 and the brakes got supper hot about 400F. Hub where cold as ice and the air Temp is about 35F today, there snow on the ground. Just did bakes on it last weekend. Brakes are adjusted right when I jack up the truck the wheels spin freely no drag. But now the pedal got really hard to push and when I drain the air tanks pedal is still hard. Jacked the truck up after they got hot and can not spin the tires. But after about a day of sitting the brakes release and tires spin. Could the air pack be holding air pressure and how dose it release air pressure.

 

[porkysplace]

Yep , air pack most likely needs rebuilding . When you said you did the brakes did you use D.O.T. 5 brake fluid ? If you mixed D.O.T. 5 and D.O.T. 3 that could cause this also as it gels the brake fluid.
New-Style (Short) Airpack Teardown & Repair with Photos

 

[gringeltaube]

Before anything else - read this post...
Your issue might be as simple as a MC-pushrod adjusted too long!?


(thanks to ecbarnum for his very detailed explanation)

 

[WhoMe08721]

Drained all brake fluid and replaced all bake fluid with MIL SPEC DOT 5 SILICONE BRAKE FLUID

 

[WhoMe08721]

Thanks gringeltaube

 

[texas30cal]

As gringletaub said brake rod too long or a tiny passage in the master cylinder can get clogged and cause this as I’ve seen it many times on cars, atvs and side by sides, it causes the dragging/not releasing brakes and the hard pedal with no free play.

 

[bigmike]

Exactly what happened to me.

 

[TGP (IL)]

Open the valve just slightly on the service brake glad hand.
That's the one on the left rear.
If problem goes away it's the air pack, if not it's the master cylinder.

Tom

 

[gimpyrobb]

You can also open the glad hand on the passenger(or is it driver? I forget!) side of the truck. If there is constant air coming out, the airpack is suspect.

 

[TGP (IL)]

You can also open the glad hand on the passenger(or is it driver? I forget!) side of the truck. If there is constant air coming out, the airpack is suspect.

Service air should be on the left rear. That's the air that applies the brakes.

Emergency or Charge air is on the right rear (pass side)
That's the air that supplies the tanks or system on the trailer and
Used for Aux. air ie tires, wrench, etc.

In the DOT world Emergency. glad hand is Red
Service is Blue.

That's why I said Left (drivers) Service air from Air Pack.

I'm sure you have forgot more than I know

Tom

 

[texas30cal]

The OP drained the air tanks

 

[Big Tom]

What happened to mine once was the cup in the master cylinder swelled and blocked the return port just enough for the air pack not to fully release.with truck running and with brakes stuck pull the gland hand cover on the drivers side if you get air out the pack is not released,could be back pack or relief hole in master cylinders clogged by dirt or cup ,you can take fill cap of master cylinder and stick a small wire in the biggest of two hole ,if the air stops coming out then you will know the problem is not air pack it’ the master cylinder , if no air came out when you opened glad hand and the brakes are stuck you have problem in the drums with wheel cylinders or springs ect.hope this helps !!

Big Tom

 

[Katahdin]

I had bolts inside a drum come loose and get jammed up between the drum and brake shoe, that caused a hard pedal problem for me. I found the problem on the 5th drum I opened up...

 

[WhoMe08721]

So the problem was the MC-pushrod adjusted being too long. That Fixed the problem of the brakes locking up. But now the bake are still get hot and the hubs are cold as ice. Around 70F in the front and 260F in the Rear. I am think the rear are not adjusted right going to readjusted them this week by (TM 9-2320-361-20 8-. Also what should the temperature be on the Brake drums be after drive and how fair should the brake peddle go down when the brake are apply at there max.

 

[WhoMe08721]

 

[cattlerepairman]

It is not possible to give an absolute temperature of the brake drums after a drive - it depends on how much brake use occurred. I would say that after a leisurely drive with the empty Deuce on mostly level ground where you used the brakes to slow down a few mph a couple of times and maybe to come to a complete stop once or twice from 30-40 mph, they should be warm, but not hot. 70 degrees F sound very reasonable. 260 is definitely too hot. It can be as easy as one shoe being a tad to tight and constantly dragging.

 

[Big Tom]

You really need to jack her off the ground and spin the wheels by hand the brakes should not be scrubbing the drums . If you take out the axles on one side it makes it easier to turn without jacking the hole truck at one time .

Just my thoughts
Big Tom

 

[rustystud]

You really need to jack her off the ground and spin the wheels by hand the brakes should not be scrubbing the drums . If you take out the axles on one side it makes it easier to turn without jacking the hole truck at one time .

Just my thoughts
Big Tom

I agree with "Big Tom" here about the axle shafts. When adjusting the brakes leave the axle shafts out. That way you will get a much more accurate feel for brake shoe drag.

 

[Floridianson]

When either adjusting the wheel bearings or brakes leave the axle shafts out.

Just a thought but the "axles" would already be out to get to the wheel bearings.

 

[rustystud]

When either adjusting the wheel bearings or brakes leave the axle shafts out.

Just a thought but the "axles" would already be out to get to the wheel bearings.

Yes, very true ! Unless you have magical powers like all heavy equipment mechanics do !
I guess my mind must be going like yours. Old age and all that.