Removing vacuum actuator

Shadowfire

New member
Did you figure this out? I had a 90 YJ and that system is vacuum actuated by shifting into 4x4 if I remember correctly there are 4 vacuum lines that run under your Jeep red/yellow/blue/green goin to transfer case it’s been a while and black for the 4x4 lite Anyway is your 4x4 lite on you dash on? Or have you raised you jeep to verify the axle is locked? The reason I ask is the 4x4 light can be on and the axle not locked. It’s common for the vacuum system to leak and not lock but I guess if your lines are crossed you could always be locked or just indicating. There is a mod that you can do that uses a cable system to engage the 4x4 manually if your vacuum system is bad..that being said and if memory serves me right it’s not dry there and you can’t pull it without fear of fluid loss. The common problem is the diaphram that actuates the lock sleeve dry rots and fails . I don’t have the service manual for that Jeep anymore I gave it to the new owner for his reference. Great video on YouTube that explains how it all works Hope this helps


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Fezz89YJ

New member
Thank you for your help no the light doesn’t come on at all no matter where I put the transfer case in I’m thinking my whole system is just bad.


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Shadowfire

New member
I think the actuator on the axle has 4 vacuum lines the black one turns the light on or off and the 2 yellow and a green you can disconnect those and see if any of them have vacuum same at the transfer case Red is the supply Yellow and green are the actuator on off blue is simple a vent these are easily accessible under your Jeep my Jeep was carbed and my lines ran down the passenger side with A T @ the firewall across to the carb follow them from the Xfer case up they are in a protective sleeve fuel injection Jeeps may be different.


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Shadowfire

New member
PS . The amount of fluid at the actuator should be below the line for losing a whole lot if removed. Raise the passenger wheel the fluid should go to the driver side. If The vacuum stuff is all good I would order a new one and just replace it it’s not an expensive part but that’s subjective. Good luck


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