A couple of ARB questions???

[Chuck K.]

I am trying to help out a friend who just bought a 75? CJ-5. chevy 350 and turbo 350. Frame off restoration. I has ARB lockers front and rear but they dont work. We tried trouble shooting it tonight but he has no info. on the ARB from the previos owner.

I jumped the relay and the pump came on. We then found where a + wire had been disconnected behind the dash, this wire appears to be the "trigger" wire for the relay. Once I put 12v to this wire the compressor came on and stayed on for about 30 seconds and would not cut off until I removed the 12v. Both front and rear switches where turned off. Not knowing anything about ARB's I would still think the pressure switch should have opened up and turned off the compressor? This is probably the reason this wire had been disconnected.

My first question: Is there supposed to be a master switch that energizes the relay(that runs the compressor) or is the relay energized once the front or rear ARB switch is turned on?

2. With both front and rear ARB switches in the off position should the compressor even come on?

3. About how long should the compressor run before the pressure switch shuts it off? ( with both front and rear lockers turned off).

4. If the compressor continues to run non stop should I suspect the pressure cut out switch or a bad compressor that wont develop enough pressure to trip the switch?

Thanks for any information, as you can tell I know very little about ARB's other than what I have read here and on other forums. Chuck

[ScottyY2K]

Mine is set-up with three switches at the dash.
1. Compressor
2. Rear Locker
3. Front Locker

When I hit the trail I fire the compressor to have air in the system and ready to engage the lockers. So I'd say has it is ok for the compressor to be on without either locker engaged (questions 1 & 2).

My compressor runs for about 15 seconds when I first fire it up. It'll then stay off until I switch a locker on. If the compressor continues to run I'd look real closely for leaks and then suspect the pressure switch. (questions 3 & 4).

Someone that is an ARB expert will probably chime in here soon. Luckily mine has worked flawlessly since it was installed and hasn't needed any trouble shooting.

[blkTJ]

My understanding, although limited, is that there should be 3 swithces. One for the operation of the compressor, and two to engauge the lockers. The positive juice to the locker solenoids is usually tapped off the post lead of the compressor switch, meaning you can't turn them on unless the compressor is active. The relay should only be involved in the operation of the compressor. The fact that the compressor won't turn off tells me you either have a serious leak or no pressure switch (or one that doesn't work). Hope this helps, it's all I've got to offer.

Brian.

oh yeah, if I'm wrong here, let me know.

[DirtDawg]

My last two offroad outings taught me lessons about my ARB's...

Last month at Rowher Flats, my ARB compressor wouldn't engage and spool up pressure. Problem?: A crusty rusty 30A fuse. Solution?: Scraped end cap on rock as a temporary fix, then later replaced fuse using dialectric grease to prevent recurrence (and carry spare fuses from now on!).

Last week, heading up Lockwood-Miller, my compressor engaged but wouldn't shut off. Problem?: Air escaping at compressor's large O-ring. Solution?: Back-off compressor end cap compression bolt (14mm head), allowed O-ring to pop back into place, then retightened. Problem solved!

Jeff
(OK, so I was WAY overdue for a post here! )

[Stu Olson]

Originally posted by Chuck K.
[B]
My first question: Is there supposed to be a master switch that energizes the relay(that runs the compressor) or is the relay energized once the front or rear ARB switch is turned on?

Yes, a normal ARB wiring harness will only allow the locker solenoids to engage after power has been applied to the relay that controls the compressor. In fact, the factory harness, without mods, will only allow the front locker to engage after the rear locker has been turned on.

2. With both front and rear ARB switches in the off position should the compressor even come on?

Providing you have the master switch turned on, yes, the compressor will come on. When you first turn on the master switch, the compressor will usually run for about 15 or 20 seconds, as it raises the pressure until the pressure switch cuts off the relay.

If you do not use the lockers for some period of time, the pressure will eventually drop (system leakage) and the compressor will turn on and bring the system back up to pressure again. My compresssor goes well in excess of 30 minutes on a leak down test (actually I quit testing it when it hit 35 minutes as that was well over the minumum time that ARB recommends).

3. About how long should the compressor run before the pressure switch shuts it off? ( with both front and rear lockers turned off).

15 seconds, give or take a little bit

4. If the compressor continues to run non stop should I suspect the pressure cut out switch or a bad compressor that wont develop enough pressure to trip the switch?

Either the pressure switch has shorted contacts which means the compressor will be forced to run until it burns itself out.....or.....the system is leaking so badly that it can not maintain pressure so the compressors runs continuously. I have seen the latter but not the former.

[Chuck K.]

Thanks everyone, I will print this and take it with me when I go over his place and give him a hand.. Chuck