1994 SR Rear Locker Pump wont Shut off?

[skeet1687]

Like the title says when I engage my rear locker the pump won't shut off...the rear locker light indicator remains solid(not flashing) but the pump itself wont turn off I can hear it still running any ideas on whats wrong? Theres an SR at the local junk yard should I replace the pump or is it a different issue? Thanks in advance for any advice!

[Shovel]

The diaphragm in the locker has a tendency to die sometimes.. and it's no longer made/available new.

[skeet1687]

that sucks is that a part of the air pump or is that in the diff housing? aka can I fix this by getting an air pump from the junk yard or do I need to replace the entire locking mechanism in the diff housing?

[skeet1687]

my apologies didn't read your post well enough.....how hard is it to get to this diaphragm? do I need to take the whole entire rear axle apart?

[Shovel]

To remove the diaphragm you need to remove the 3rd member from the axle.   That means supporting the vehicle frame,  draining the diff, unbolting the drive shaft and ratchet strapping it  to the muffler, unbolting the wheel bearing/brake assemblies, loosening parking brake cable brackets, pulling the axle shafts out around 4 inches, then removing the nuts around the third member and finally pulling that heavy bastard out without breaking your hand.

Then figuring out how to deal with the fact that diaphragms are discontinued.

[skeet1687]

LOL on a side note how do I know for sure its the locker diaphragm? could it be the pump that's faulty I'm asking because my rear locker dif light stays constant when I engage the locker wouldn't the light be blinking as it would not be able to create enough pressure in the diaphragm with it being torn or what not? was reading somewhere that the pump itself also has a diaphragm that can fail?

[Crumb]

 Well technically the diaphragm has been superseded, unfortunately you need a new pressure plate too which is like $100 on it's own. Start by using soapy water along all the hoses and connections and find the leak(s). You might just need to replace a hose or two if you're lucky. 

[RyanY]

The locker pump operates at only 5 psi. Your light comes on because the locker is likely engaging, but the system has to continue to keep the pump on to maintain that pressure. It would be worthwhile to trace the air line from the compressor all the way to the rear diff to make sure it's intact and undamaged. Spraying soapy water on any suspect areas will tell you if there are any air leaks. If you find no issues with the line then you're stuck with attempting to repair your diaphragm or finding a new or used replacement somehow.

[skeet1687]

Well technically the diaphragm has been superseded, unfortunately you need a new pressure plate too which is like $100 on it's own. Start by using soapy water along all the hoses and connections and find the leak(s). You might just need to replace a hose or two if you're lucky. 

Hey toasty what do you mean by the diaphragm has technically been superseded? does this mean there is an updated diaphragm I can purchase and use on my 94? not sure what you mean by this...also I'm guessing I need to rip the entire back seat and carpet out to locate the hose? I know the pump in under the back passenger side seat but it dosent seem like I can get to the pump/hoses without taking the entire back seat and carpet out?

[Crumb]

 Yeah there is a new part but you can't use that diaphragm on it's own, you will need to update the entire part. The hoses and compressor are easy to access, check the outside hoses first because they are easiest then do the inside ones. You'll need to unbolt the compressor, it's inside the left storage compartment.

[RyanY]

You'll need to unbolt the compressor, it's inside the left storage compartment.

Right side storage compartment, actually.

[skeet1687]

Experience says diaphragm. Mine leaks also. Do you have a part number? Stealer only I assume?

Does your locker still work? if so do you still use it on trail?

[Crumb]

You'll need to unbolt the compressor, it's inside the left storage compartment.

Right side storage compartment, actually.

 Right!

[JohnnyBfromPeoria]

You'll need to unbolt the compressor, it's inside the left storage compartment.

Right side storage compartment, actually.

Just say passenger side.

Mine's been leaking for like 10 years. I think I bought the last original diaphragm left in the U.S. when I got mine, but it remains in the box because it still works. I just have to "warm up" the diff first and hit the switch repeatedly until it stays on; the pump runs constantly, too, at least after a few tries.

John B.

[PA_JERO]

What can't leak on that system? Nothing! Check your compressor because the head can crack and that will need to be replaced. All hoses heading down to the diff can leak as well, so check those. Also, in the diff there is a very small section of hose going from the housing to the diaphram that can leak. I did all of my stuff a couple months back and found several things that could and did potentially leak. All of which is very easy except the diaphram on the diff housing. That's a bugaboo.

My opinion is to find a gen 2.5 and steal it's 3rd memeber, re-gear it to your liking and use that new housing but replace the diaphram when you re-gear. You can buy a diaphram for those readily available. Early gen 2 locker set ups are discontinued. You can buy a new updated diaphram but that requires a new pressure plate like toasty expressed, but the problem with that is they are 3 months out of japan, they are about $300 plus buying a new diaphram which was $150. If you aren't handy or equipped to do your own ring and pinion set up, calculate labor. Easier to find a gen 2.5 in a wrecker with a locker and there is all your updated parts. Most junkyards would hopefully let a 3rd member go for about $100.