PacBrake - Am I Missing Parts?

[Jackn]

I am trying to identify my existing PacBrake so I can order a new one. In examining my brake, I found what appears to be a missing threaded plug (the large gaping hole) in the air line as it enters the air cylinder. Is anyone familiar enough with their PacBrake to tell me if the end of that fitting should be plugged up in order to make the PacBrake work? Thanks again! Jack

[Happycarz]

Jack,
You are right about the hole in the end. Hopefully, you didn't get too much junk in the cylinder. Replace the broken piece with a brass 90* fitting.
Get some PacBrake oil, or equivalent, and lube according to this chart.

[DtBt]

The picture is not really clear to me but I do know there is supposed to be a quick release valve ( the thing that makes the right angle I think). The purpose of the quick release valve is to make the butterfly close quickly after air pressure is removed. The hole is where the purged air comes out if I am correct.

[sjholt]

There is a cone shaped rubber dealie that goes in there and an insert that screws in and holds it there, it is for releasing the pressure when it is turned off. Call PacBrake and tell them what you need.
Now I'm going out to check the tightness of mine since I did have it apart!
HTH

[Jackn]

Thanks guys...

I think I'll go try to replace my missing parts for now, but it sure is temping to upgrade anyways..... Happy camping, everyone!! Jack

[RonNBama]

Before you guys with knowledge go to bed, let me ask for clarification here. If that opening is as shown, there will be no pressure applied to the PacBrake piston at all, right? There would only be a big hiss and loss of air pressure while the PacBrake pedal is pushed...? I noticed my PB was not functioning as well as I expected and found an open port at about that same location (slightly different models of PB). Mine had a threaded hole (cannot recall the exact specs but the same size and pitch as a large grease cert). I hooked up a 12V signal to the solenoid and all I got was a pssssssttttt out of the opening. Figured what the heck and plugged it. PB cycled through normally when activated. Is there supposed to be a relief port in that hole? Looks to me like the PB lets off immediately when voltage is removed from the solenoid.

[Happycarz]

The solenoid that opens and sends the supply air to the cylinder is what is known as a 3-way solenoid. When voltage is applied to the solenoid, it opens letting air go to the PacBrake cylinder. When voltage is removed, the solenoid shuts off supply air and opens a port in the top of the solenoid to release the pressure in the line to the cylinder.

When I replaced my Cummins/Jacobs E-Brake with the PacBrake, the kit contained a standard 90* brass elbow to connect to the cylinder.

Verify you have a 3-way solenoid by disconnecting the 2 wires to it and applying 12v and ground to the solenoid. It doesn't matter which wire, or terminal, is hot and ground. The cylinder should actuated with voltage applied and the give a little psssst sound as the cylinder returns when the voltage is removed.

Jack,
Yours won't do the above until you replace the 90* fitting.

[RonNBama]

Exactly the response I was getting Happycarz. I assume that a plug vibrated out of mine and now all is well.