2004 Rubicon front locker won't engage

thatwhitetj

thatwhitetj

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Joined
Mar 24, 2019
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20
Location
pennsylvania
I just picked up a 2004 Rubicon yesterday, first rubicon after wrecking my 97 so i’m not too familiar yet. PO had the 4wd switch replaced because 4wd light on dash would not light up.
Now the rear locker locks fine and i can tell for sure, but the front locker just blinks and won’t engage. I switched the lines and vice versa, rear locker blinks and front clearly locks, and i lose almost all steering so i know the lights on the dash are telling me correct.

Bad lines are ruled out since it locked when the lines were swapped, same with the plunger for the light.
Is this a pump issue and do I need to replace the front pump or what can be done to fix the issue?
 
Test the locker by low pressure (5-10lbs) to see if the locker is working. If it is working then it could be your pump. Check for a bad electrical connection before replacing the pump.
 
Sorry should’ve mentioned, the pump works and runs continuously. I know it’s 5psi so I won’t feel much, but i can feel the light amount of air coming out of the pump when i pull the line and put my finger over it.
 
I tried that yesterday for almost 10 mins when buying the Jeep, took the deal for $500 off as is.
Like I said above, I just went out and swapped lines on the pumps and the front locked just fine within a couple feet, but now the rear wouldn’t lock at all. Went around the block slowly and in reverse and the rear still wouldn’t lock.
Starting to think it could be a bad front pump, but again, I can feel the air coming from the pump so that’s leading me to believe it’s not bad.
 
So it sounds like you have:
  1. Ruled the locker is ok
  2. The line to the front is ok.
  3. Power is getting to the pump

So it has to be the pump. I have a box of rubicon pumps that all are broken. Some of them sound like they are working but if you place your finger over the outlet they don't stop pumping (they should stop when max psi is hit).

Can you confirm that the front pump sounds like it is running but when you place your finger over the outlet it keeps sounding like it is running.
 
It has to be the front pump. I just pulled the line off the pump and put my finger over it, heard it get deeper like it is building pressure but it will not turn off after 30 seconds. They are a little rusty so it doesn’t suprise me, I will replace and see how everything works then. Thanks for being so quick guys
 
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I have a bunch of them that do that I suspect it is due to a leak internal on the pumps. My only solution so far has been to buy a new pump.

My new pumps were moved under the hood to make them last hopefully longer.
 
New pumps are $$$. There is a thread out there listing all of the other vehicles which use the exact same pump - was quite a list. Easy way to same some cash.
 
Just wanted to share my locker fix in case someone else has the same issue. I tried Jerry's S turns to engage but nothing happened. I then tried swapping the hoses to see if it was the pump. Neither pump would go for more than a second. When I put the hoses back in order I notice the issue. Some bonehead (me) switched the intake and output hoses when moving the pumps to the engine bay. I switched them up and both lockers engaged immediately.
 
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Reactions: Feralkid
If the pump runs continuously, even when you put your finger over the output port, you will need to replace it.
 
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