LS1Steve

I know you are supposed to run an 80/110 pressure switch on an ARB locker compressor, but is there any danger to the ARB or diff if I run less pressure?

The f-in compressor I have was hitting 115psi just fine until I mounted it in the truck, now it won't go past 40-45psi. I added a guage to the plumbing but thats all, and I can't feel any leaks, I dont know wtf happened.

The ARB engages though with only that pressure. Is it fully engaged? Is there such a thing as partially engaged? Its either locked or not right?

KyleT

is your gauge correct?

LS1Steve

yes, brand new gauge

tc

The big problem is if the pressure is too high - you can blow the seals inside the diff (not that hard to repair, but you have to pull the thirdmember). If the pressure is too low, it may not engage. I don't think it's an "all or nothing" engagement though - I think it could not move the locking mechanism all the way and it grind.

Looks like you mounted the compressor under the truck ( a ways from the battery). What size wire did you use? What's the voltage at the compressor?

I would call ARB.

AxleIke

Call ARB.

I had trouble w/ my comressor, and they shipped me a new one as soon as mine hit their door step. 8 bucks in shipping, but worth every penny. The guys up there are top notch, great customer service.

AH64ID

I wouldnt operate it on too little pressure.. There is a heafty spring in there that you have to depress to get full engaugment... I dont know the specs of it, but I wouldnt want to find out the hard way... find out your air pressure problem...

LS1Steve

well alright then, I was assuming the pump was the problem, but when i removed it, I get 110psi again. I new something was funny when I could smell the diff fluid when I engage the pump, the diff or arb has a leak somewhere. I can't tell where, where should I look? This ARB was replaced under warranty and has only been in the truck for about 3yrs, and used once or twice briefly, not abused at all, light stuff. I am positive it never had excess pressure, what now?

tc

Get a spray bottle and put some soapy water in it, then spray the various connections. When you see bubbles, there's your leak. If that shows all good, remove the diff fill plug and see if air comes out of there. If so, it's probably the little copper line that goes from the housing to the actuator. Two failure modes (Don't ask how I know):
There's a little clip that holds the seal onto the diff. The clip can come undone and the air goes into the diff housing instead of the locking mechanism.
The copper line can get too close to the ring gear and wear a hole in it if you're not SUPER careful when installing the thirdmember.

I had some air leak issues with my rear locker, but worked them out and haven't had an issue since. The lockers have been the best money spent on my rig so far.

AH64ID

Is looks like your pump is upside down mounted, are you sure it can do that?

As far as the fluid leak, check what tc said... I always noticed a gear lube smell near the air pump from the pressure line...