ARB locker issues (1 Viewer)

[Brian894X4]

I need some suggestions from anyone with ARB airlocker experience.

I have two air lockers on my FZJ80 using a small ARB CKSA12 compressor.

Today, the ARB relay failed and turned on without switch power and forced the compressor to run without the switch turned on. In the process of doing this, the compressor ran for several minutes without the benefit of having power cut off via the pressure switch.

So, I replaced the relay and now when I turn the compressor on, it runs for a few seconds, then shuts off, which normal, with the smaller compressor and pressure switch, but then it immediately turns back on and runs continiously.

There is no obviously leak anywhere near the compressor. I can't tell if there's a leak inside either of the housings. I suspect (hope) the pressure switch has failed, but I'm not sure. I don't think anything has completely failed in the diffs, because if I disconnect the pump after it's run for a little bit, can turn the locker solenoids on and off several times with them venting air each time.

To add to matters, I've noticed that I've got gear oil leaking out of both solenoid vents.

I have three major questions while I continue to trouble shoot.

a) Is it possible to accidently overpressurize the locker or internal lines and have them blow or maybe the seals inside the diff? Can the ARB air pumps make too much pressure if they are left to run without a pressure switch?

b) I've heard that o-rings can fail and be replaced. What o-rings are these? Are there o-rings I can check that don't involve removing the differentials?

c) Has anyone had or seen an ARB pressure switch just fail like this?

 

[CycloSteve]

My compressor pressure sensor died with less than a year of use, of course while going up a muddy steep hill. I had most of what you are describing happening with my rig, compressor running incessantly. There is an overpressure valve on the tank, so you should be OK with the lines, O rings, and lockers IMO. I contacted ARB and they sent me a new one which arrived in two days time. Easy to fix, and no issues since.



Steve

 

[Brian894X4]

Thanks for the reply. It gives me some confidence that the compressor probably didn't pop anything since it only overran for about a minute. Did some more testing with a gauge and the pressure sensor is definately toast.

So, it cuts off at 100 psi, like its suppose too, but then immediately resets and with the compressor running, it shoots up to 140+ in 2 seconds flat. I'm sure the lines and ARB have seen whatever the max output is of this ARB compressor, because without an airtank it rises fast. When you let out the air pressure, the sensor clicks at 70 psi, like its suppose too, so the pressure part of the sensor is probably working but the electrical part is sticky for some reason.

Now, I just need to figure out how bad having all this gear oil in the solenoids is and why it's there.

 

[jonheld]

You're getting gear oil back to the solenoids because the system over pressurized the lockers and blew the seals. They were not designed to see 140 psi. Your use of a gauge will put you on the correct path. Run the compressor till it sees around 70 psi and see if the lockers will reliably engage. Then purchase a fixed pressure switch with cut in at 70 and a cut out at 90. Or find an adjustable one. Run the pressure as low as possible to get positive locker engagement.

The 3rds need to come out to replace the seals, but IIRC you can do that without removing the diff carrier from the housing. Best to ask ARB. Their customer service is outstanding and they are always willing to help.

 

[desertdude]

Brian, Might not be your situation but.... a couple years ago, I have had an issue (inside the rear diff) where the copper air line cracked where it is soldered coming from the locker seal assembly - this created the leak and moved diff oil through the lines as well.

Fast forward to last month at the Rubithon, the rear locker leaked and would not engage, (compressor running, would not pressurize and shut off.) I am going to guess its the same issue (copper line cracked at the solder joint on the seal assembly). I just received the parts and will dig into it in a few weeks and report back.

Also - I installed "L" fittings under each solenoid switch with mini tubing running into a small catch jar. This idea ( and fittings) came from Christo, this allows me to monitor any oil in the lines that runs as far as the switches - when everything is working properly, there is a very miniscule amount of diff oil in the jar.

 

[Cruiserdrew]

The 3rds need to come out to replace the seals, but IIRC you can do that without removing the diff carrier from the housing. Best to ask ARB. Their customer service is outstanding and they are always willing to help.

I had a pressure switch fail and the solenoid fail. There is a better plug in Solenoid to use that has a higher current rating and is US made. I'll find the part # and report back. I got it at Carquest.

Regarding the seals and o-rings. There are 2 areas of concern, and both require the carrier come out of the differential housing. Newer style ARBs with the spring clip on the inlet o-ring housing thing may be different.

The inlet o-rings are easy/cheap. They should be replaced every time you have the diff open. There is a newer version of those o-rings that has a square cross-section that supposedly lasts longer.

The more difficult seal is inside the locker and it too can fail, and requires the disassembly of the locker itself to service.

Anyway, you gotta pull the 3rds to figure it out.

 

[Brian894X4]

Well, let's just theorize for a second that the air pump over pressurized and blew the seals inside the locker.

Seems to me that ARB could have better designed this system being as I'm using their pump and pressure switch and if/when their stupid pressure switch fails, the pump is going to zip up the pressure in the lockers real freaking quick. Why not have a pop off valve on the compressor that it prevents it from exceeding whatever the design limit of the seals are on the diffs?

If a $15 pressure switch failure really is going to cause me to have to pull the diffs, my opinion of ARB lockers will sink right into the toilet, despite years of otherwise hassle free service on two seperate rigs.

That said, the lockers do appear to be able to hold pressure. I can't say for how long because there's a minor air leak in the connections in the engine compartment that I need to sort out, but it's not dumping air in the diff and the pressure switch is definately bad. So, if the those seals are blown, they aren't blown to the point that it wont' hold air pressure and I'm pretty sure the lockers are engaging and disengaging normally.

Note to self...next time...electric lockers!

 

[Brian894X4]

If anyone is interested, this is the response I got back from ARB......if their head tech guy is correct, it certainly makes me happy and now its time to check out my breathers. I have long breather extensions, but they could still be plugged up and I'm using the stock breathers just on the end of a long hose, which might be an issue.

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Hi Brian,
We have the pressure switches here and I will have one sent to the address you have provided. The additional pressure will not damage anything in the system and is not related to the oil coming from the solenoids. Oil from the solenoids is typically caused by pressurization in the axle housing. With Toyota's this is commonly caused by the 1 way vent valves getting stuck closed resulting in pressure building as the axle warms up. I would suggest cleaning the blue airline and solenoids with brake cleaner (unhook the lines at the axle housings) followed by compressed air. Next, replace the vent valves (assuming you still have them) with a barbed fitting and fuel line to allow the axles to breath properly. More than likely this will resolve the issue, however, if the oil does return please contact us at the number below and we can discuss it in greater detail.

 

[desertdude]

Interesting... I will have to check my breather line as well they terminate high up in engine compartment, with the OEM breather valve at one end.

Thanks Brian

 

[Cruiserdrew]

Pasquale-

Top those lines with an inexpensive fuel filter. That factory valve thing is a dumb idea.

 

[TrickyT]

...Today, the ARB relay failed and turned on without switch power and forced the compressor to run without the switch turned on....

Others have addressed the oil leakage and seals and stuff, but I wanted to say that relays don't fail like this. Their coil has to be energized for the relay contacts to close and run the compressor, so something else in the electrical system failed and that caused this to happen. It sounds like you already suspect the pressure switch, but it could also be a short in the wiring. You need to track down the root cause so it doesn't happen again.

 

[desertdude]

yeah - its a simple steel ball ...duh!

Pasquale-

Top those lines with an inexpensive fuel filter. That factory valve thing is a dumb idea.

 

[Tools R Us]

yeah - its a simple steel ball ...duh!

Some are a rubber flap, ether type tends to get stuck. The design allows air to escape as the diff heats and doesn't allow air in as it cools, so sucks from other leaks, like the knuckle seals. The tends to pull knuckle greases into the diff fluid and increases the chance of moisture contamination. As Drew said, a simple filter is far more effective, I prefer the VW type fuel filters, light, cheap and effective.

 

[jonheld]

Others have addressed the oil leakage and seals and stuff, but I wanted to say that relays don't fail like this. Their coil has to be energized for the relay contacts to close and run the compressor, so something else in the electrical system failed and that caused this to happen. It sounds like you already suspect the pressure switch, but it could also be a short in the wiring. You need to track down the root cause so it doesn't happen again.

IIRC the ARB pressure switch is NC and breaks on high pressure. its a switch, not a relay.

 

[CycloSteve]

Pasquale-

Top those lines with an inexpensive fuel filter. That factory valve thing is a dumb idea.

x2, and exactly what I did when extending my breathers...cost $4 and definitely no restrictions whatsoever. Gained 2+ feet of water-crossing ability, should I ever get the nerve to go scuba with my rig...need the snorkle first.

Brian, glad to hear that the seals themselves were not damaged...that was my primary concern with my rig when my pressure sensor went kaput. Luckily it seems as if the overpressure valve does its job well on the CKSA12 compressors.



Steve

 

[TrickyT]

IIRC the ARB pressure switch is NC and breaks on high pressure. its a switch, not a relay.

Got it. I was going off what Brian said in his original post: "the relay failed and the compressor ran without the switch being on." He must have meant the pressure switch failed. It also must mean he's wired his compressor to always have +12v running to the motor. So if this happened with his truck parked and him not around he'd come back to a very dead battery.