New Style Air Brake Switch issue. Air Pack stuck?

[HunterW]

Thanks to the replies on my thread, I now have a new brake master in the truck. Installed the new style air brake pressure switch. Bled the master and all 6 brakes.

The brake lights will come on... and then stay on. I assume this means my air pack is malfunctioning?

I read another thread that mentioned the air pack should bleed off (pssshhhtt) after you release the brake pedal each time? Is this true? Mine has never done that.

The pedal will feel good at first pump, each after the pedal is VERY stiff and almost impossible to stop the truck. This would mean there is no longer air assist until it somehow bleeds itself off?

My brake lights are staying on because there is still air built up in the air pack assist system even after I release my foot off the brake pedal. It probably takes a good 5 minutes before the lights will go off after depressing the pedal and letting it sit.

Thanks for any help!

 

[cranetruck]

Take a look at this picture, the "breather" line must vent after each use. Open it and try pumping the brakes.
Second image shows where the new stop light switch is supposed to be connected. You didn't put it in the vent line did you?

 

[HunterW]

I didn't put it on the vent line. From that first picture, I feel like it went on the Trailer Service Air Line... Is this correct?

In the second (cartoon) picture, it doesn't show the air line that goes to the rear of the air hydraulic cylinder. I did remove this line, depressed the brake pedal, and air came from the air pack and would have headed toward the back of the air hydraulic cylinder if the line had been on. I hope that makes sense?

 

[emmado22]

Double check your placement of the switch on the correct line.. If you put it on the wrong line, you have the problem you describe. Ask me how I know....................

 

[HunterW]

I wonder if anyone has an actual picture of it installed on theirs. According to the diagrams I have it on the correct line.

I am worried that my brakes don't release pressure (PPSSSHHHH) after I release the pedal. I think the air hydraulic cylinder is holding the pressure in which is keeping the brake air switch activated.

 

[m16ty]

I wonder if anyone has an actual picture of it installed on theirs. According to the diagrams I have it on the correct line.

I am worried that my brakes don't release pressure (PPSSSHHHH) after I release the pedal. I think the air hydraulic cylinder is holding the pressure in which is keeping the brake air switch activated.

Seems to me if that was the case your brakes would be locked up.

 

[jwaller]

this is the best I could do in the pouring rain with skid plate on.

 

[HunterW]

Seems to me if that was the case your brakes would be locked up.

You make a very good point there...

And jwaller, thanks for the pic attempt! From what I could tell I have it on correctly...

 

[AN/ARC186]

Not sure if this helps but.......

 

[progun]

Old thread but I am having the same problem. My air pack looks just like the one pictured here. New switch in the new location. My brake lights stay stuck on too. Did you ever fix it Hunter?

 

[toddm]

This might help

 

[rlwm211]

There are two possibilities that can cause the brake lights to stay on.

1) the master cylinder has a "relief port" which is a tiny port into the main bore ahead of the piston. This serves to allow the fluid to return to the resevoir releasing the brakes. An additional possibility in the master is the "check valve" on the end of the master return spring. This valve is designed to relieve pressure down to 10psi or so which is enough to keep the piston seals in the wheel cylinders in proper position to promote sealing and prevent leakage. If the port is blocked or the check valve is sstuck this can keep the brakes applied.

2) The actuator valve in the air pack is sticking and the air is applied, but not reactively to the pressure of the input. That would explain the situation where the harder you push the less braking reaction you seem to get. This would also allow a low pressure application of the air cylinder and turn the brake lights on.

To test for the master and possible probelms, remove the fill cap, and gently apply the brake pedal with your hand while watching the resevoir. Initially you should see a back flow into the resevoir, and then the pedal should get firm. When you release the pedal you should see a flow back into the resevoir. If this all happens your master is working properly.

As mentioned in the post, you should hear an air release when you release the brakes with air in the system. Obviously the truck should be off.

While a completely accurate diagnosis is impossible via the internet my guess is your air pack is sticking. Many will recommend adding oil to the piston area. This does little to lubricate the operating portion of the air pack. I would consider injecting a small amount of air tool oil in the INLET line to the air pack. The build up air and apply and relase the brakes several times. Add a very small bit of oil. I am talking a squirt or so of an oil can. Not an ouce, or even close to that. If the actuator assembly and the compensator valve are stuck this may persuafe them to loosen up.

If this does not work, I would rebuild the air pack.

Hope this is helpful

RL

 

[HunterW]

I have not yet resolved the issue. Mainly because work has kept me on the road for the past few months and away from the deuce.

Check the pictures I uploaded and make sure the lines are in the correct locations.

I removed the front wheel cylinders to find one side of each leaking and the other completely seized up. I then removed the air pack, tore it down, only to find massive amounts of corrosion everywhere. I don't think any of it is able to be salvaged. I am planning to order 6 new wheel cylinders and a new air pack. This will mean an entire new brake system except for lines.

It looks like someone really had some water in the system at some point. The corrosion was horrible and almost everything was seized up.

On a side note: my front axle/hub nuts (the 3" eight sided ones) were HAND tight on both sides.

 

[rlwm211]

The air lines look correct as far as I can tell. The copper line that is at the bottom is the vent line of the air pack. You should have the switch hooked into the same line that goes to the rear service brake gladhand.

RL