ARB Air locker bad pressure switch (1 Viewer)

[Landpimp]

Not really asking a question but I didn't find this posted on Mud..or looked in wrong place

ARB and Compressor are 12+ years old, rear is a full floater, old original style compressor. (I have a 40 and 60 with the same set up)

But a few weeks ago I noticed my rear ARB in the 45LPB was blowing fuses. the compressor would run, then shut off like normal, I could lock and unlock the locker but then the compressor started to make funny noises, relay was clicking and boom......the fuse goes. So after picking up a few more 30amp fuses(lets call it 10) I started to test some things, swap the relay with a brand new one i had, same issue. I took the solenoid apart and cleaned it, same issue. I checked all the wiring and all was doing what it was suppose to do.

Then I noticed gear oil coming out of the solenoid when I would unlock the diff, you know....like the O ring has failed in the locker(this happened in my fj80 I think)

I changed pressure switches(with an unknown good/bad unit i had) did the same thing

So at this point I have narrowed it down to a bad pressure switch(or maybe bad compressor), pick up a new one for $15(I know I have a spare someplace)

replaced the pressure switch last night, and everything is back to working perfect......and no gear oil blowing out of the solenoid.

which makes me wonder........when the pressure switch fails does it let to much pressure into the locker? and blow oil past the O-ring (I guess I do have a question)

admitiedly I don't wheel the rigs but I like have a rear locker, I get on some slick projects and locked the rear up makes life nice.......been running ARB's since it was called a Roberts Locking Diff....actually when I got it the name had just changed to ARB

 

[Output Shaft]

The pressure switch can fail a couple ways. It could not switch off at the stated pressure and over-pressurize everything (hence the blown fuse) or it could get stuck in the OFF position and not let the compressor run.

A little oil blow-by out the ARB control solenoid/s is normal (according to ARB) and doesn't signify a problem. When the pressure is released to turn off the diff, the abrupt instantaneous release of pressure inside the locker forces a little gear oil back up through the feed line. After enough actuations and releases, the oil eventually migrates all the way back up to the solenoid.

When your pressure switch failed, the locker was getting a much higher pressure (which won't harm it) but when that higher pressure was released, it did so with much more gusto and blew any existing oil in the hose and more oil than usual back up through the feed line.
It cleaned things out.

 

[Landpimp]

Excellent ! and thanks.