xj front axle vacuum problems.

benztechnc

New member
Ok, this has probably be covered before, but I just havn't been able to find it. If some one knows what is going on then please tell me cuz I haven't got a clue.

91 xj, 4.0l.

If I connect up all the vacuum lines, i have constant vacuum to both the ends of the front axle locking actuator, which means the pressure is equaling out, and thus no lockiing or unlocking of the axle, which alas means no four wheel drive. :?|

ok if i disconnect one or the other line, it locks in and unlocks. :D so... i replaced the vacuum switch with 4 lines connected to it on the transfer case, figured that was what controls it. 2 lines in to supply vacuum, 2 lines out to put the vacuum to the front axle. also the 4wd light doesn't work, ever.

am I understanding the workings of the system right? and if so, how am i getting full time vacuum to the front axle on both sides, and how do I get it to stop and work properly?

thanks in advance!
 

The 4 vacuum lines on the transfer case switch are:
Vacuum in
Vent to engine compartment
2 lines to front axle

I'm thinking you have a vacuum source on the vent line, which along with the original vacuum source line is giving constant vacuum to both lines to the front axle.

I would find an XJ that hasn't been touched and compare your vacuum line setup to it, or have somebody on here tell you which color lines go where.
 
THanks. I've tried that. So far so good. Though I havn't had to use it all that much. I also found a ton of cracked vacuum lines and have been replacing them as I have found them.
 
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