Soft Brakes, and line question

[Rellim4560]

Lately I noticed the brakes on the deuce are a lot softer. The pedal goes down all the way to about two inches off the floor before the brakes kick in and work. I checked all the hubs and the hydro Lines I could see and there does not appear to be any leaks in the lines. I don't think it is an air problem since my air pressure gauge never moves from between 90 and 120. This morning i was going to check the fluid level in the master cylinder and try to check for internal leakage in the cylinder as recommended in the TM's. However once i opened the access panel i noticed that there was an unconnected line right on the top of cylinder as shown in the photo below. Being semi new to the deuce, is this line suppose to be connected to the brass fitting on top of the master cylinder? The TM mentions disconnecting this line but i couldn't find where it should go.

 

[deuceman51]

It's the old vent line. Later trucks had these removed because of contamination issues. Replace the 1/8 pipe thread fitting with an axle breather and then buy a tube plub for the tee that the line connects into. Check to see if you have brake fluid coming from your slobber tube on the engine. If your airpack is bad, it will start to vent out brake fluid through that tube. I just replaced the brake system on a rural fire truck yesterday and that was the problem they had.

 

[Speddmon]

It's the old vent line. Later trucks had these removed because of contamination issues. Replace the 1/8 pipe thread fitting with an axle breather and then buy a tube plub for the tee that the line connects into. Check to see if you have brake fluid coming from your slobber tube on the engine. If your airpack is bad, it will start to vent out brake fluid through that tube. I just replaced the brake system on a rural fire truck yesterday and that was the problem they had.

I would agree with what you said except for the fact that his vent line is disconnected. So if his air pack were going bad it would have just blown the fluid out of the open vent and all over the top of the master cylinder.

Also, unless yours was plumbed in differently than the stock ones the vents usually ran to the air cleaner housing IIRC. So brake fluid should have ever been coming out of your slobber tube. I could be wrong though...I have been before and I'm sure I will be again

 

[Speddmon]

If your brakes work OK when the pedal finally starts to get tension, more than likely you just need to bleed the brakes. Start with the master cylinder itself and then move to the passenger side rear dual and work your way closer to the master cylinder just like you would with a car.

 

[Boatcarpenter]

You should check your brake adjustment all around also.
BC

 

[MWMULES]

When adjusting/bleeding the brakes on a duce you start at the master then air pack before you do the right rear. Or at least that was the way my motor daddy taught us.

 

[rlwm211]

First and foremost, you need to do a primary and secondary brake adjustment on your brake shoes. While this is a pain and you need to remove the wheels to do this, it is an essential part of proper PCMS on the deuce brake system.

After getting your brakes properly adjusted, then check your pedal and see how it seems then. If the master is full of BFS and there are no apparent leaks you really do not benefit by bleeding the brakes especially if there is not any brake fluid on the back ot the tires or leaking from the backing plate and drum.

As to brake fluid from the Slobber tube, this cannot happen. Even with the brake vent conneccted to the vent tube, 9 times out of 10 the tube it connects to is not connected to the air cleaner. Even if it was, BFS would lay in the bottom of the aircleaner and go no further.

I will add if you have not done a complete brake inspection on your truck along with greasing the wheel bearings you need to get this on your to do list and this will go a long way towards sorting out your brake problem.

You have to remember that these trucks were phased out of regular duty and also PCMS many years ago and the worst thing you can do to a deuce brake system is to not use it.

I have heard learned veteran Deuce owners and collectors say that any deuce brake system that has not been completely gone through is a deuce with a suspect brake system and should not be trusted until it is brought into proper condition.