Pneumatic System Tank Draining Procedure

[davidbrady]

Taken from SpongeBob's documentation. Should also be useful for our Wanderlodges. This set of tests verifies that all air system check and pressure protection valves are working properly:


1) Start engine, pump brakes to 90psig, allow compressor to run to cut off
pressure
2) Note pressure and shut off engine
3) From under the coach, listen for any leaks. Note and repair as required
Restart this procedure if leaks were found and repaired
4) Verify no pressure drop on gauge.
5) Open Wet Tank drain valve and drain completely; close drain. Note and
record moisture / oil contamination.
6) Check Primary and secondary air gauges. Still should read 120-130
7) Open Primary brake tank drain valve and drain completely; Close drain.
Note and record moisture / oil contamination.
8) Check Secondary brake tank pressure should still read 120-130
9) Open Secondary break tank drain valve and drain tank completely; Note and
record moisture / oil contamination.
10) Open Accessory tank drain valve and drain tank completely; Note and
record moisture / oil contamination.
11) Ensuring all valves are closed, start engine, note time required for air
pressure to reach cut off pressure.
12) Document in vehicle file to build a history for coach.

In addition, I'd add:
13) Start engine and allow compressor to run to cut off pressure,
14) Open Accessory tank drain valve and drain tank completely,
15) Check Primary and secondary air gauges and verify they're at the expected psi.
16) Open Secondary brake tank drain valve and drain completely; Close drain,
17) Check Primary brake tank pressure to verify it retained its expected psi.

IOWs, work backwards.

[davidbrady]

Here's a good diagram by Meritor on general air brake troubleshooting:

http://www.meritorwabco.com/MeritorWABCO...tp9973.pdf

[GregOConnor]

Dot inspectors also do a park brake diaphram test... chock tires, release park brake, turn engine off, listen for air leak at maxicam .
I install ball valves on the parking diaphram fill line for theft protection. It got me red tagged once , but I kind of think it was a warning to step up comliancy. New lines ,new parts , and fresh paint attract dot attention . They do a good job keeping everyone safe. Dot inspections should be expanded to rv's with air and air assist.

[GregOConnor]

Dot inspectors also do a park brake diaphram test... chock tires, release park brake, turn engine off, listen for air leak at maxicam .
I install ball valves on the parking diaphram fill line for theft protection. It got me red tagged once , but I kind of think it was a warning to step up comliancy. New lines ,new parts , and fresh paint attract dot attention . They do a good job keeping everyone safe. Dot inspections should be expanded to rv's with air and air assist.