Transfer case vacuum lines.....HELP

[83 WagDriver]

Does anyone know where the vacuum line that engages the 4 wheel drive is???
My 4 wheel drive is not engaging and I believe this might be the reason.

Is this hard to fix??

[blackjeep2002]

It is easy to fix. There should be 3 hoses coming out of the firewall in the middle of the truck. One goes to a vacuum source, and the other 2 go to the shift modulator on the transfer case. You may have to dig under the dash to find out which one goes to the engine. After you figure that out, it is just trial and error with the other 2 to figure out which one engages and which one disengages 4wd. Hope this helps!
Keith

[Dive 30]

Does the dash switch 'hiss' when you switch it back and forth (with the engine running)? You should hear a short 'hiss' as the vacuum is released from one side and switched to the other.

If you look at the exact center of the firewall, there is a plastic black ball that is the primary vacuum reservoirs. Out of Driver's side there you have a hose that comes out and goes to a 'y'. This fitting goes down to a white plastic check valve, this holds vac on the 4wd system wether or not the motor is running. From there this turns into a harder plastic hose that runs to the center of the dash vacuum switch. Out of the vacuum switch you should have a bright yellow and bright green harder plastic lines. These run out of the switch, through the hole in the firewall and down to a metal triangle fitting with a rubber connector that converts to metal (steel or aluminum) lines that run back to the T-case where they go through an identical rubber triangle fitting, back to the yellow and green plastic lines and to either side of the vacuum motor. If you have (or can get, they are cheap at the auto parts stores) a hand vacuum pump, you can pull vacuum on the vacuum motor and watch it's actuation (haynes has a good write up with pics on testing the vacuum motor). Now, somewhere in there, if you have the vacuum actuated front axle (I think you do), those lines have to come off of there. Mine doesn't have those, so maybe one of the other guys can chime in there. You can also check the switch for leaks with the hand vac pump and a vac gauge can tell you what kind of vac you are pulling throughout the system. A friend of mine who is a wrencher (manages the shop at our local VW/Porsche/Audi dealership) says that the best way to troubleshoot a vacuum problem is to start at the motor and replace all of the vacuum lines until your problem goes away. Sometimes I think that is pretty sensible advice

I hope that helps

Phil

[joe]

83WD, I'll email you the vacuum diagram for the 229 and front axle.
Yours does have the vacuum disconnect axle so check out the hoses and connections there too.

[imported_Big Red]

I had the same problems you are having and with the guidence of the fsj experts, I went and purchased new hose and pipe and made my own vacuume lines. She works like a charm! Over time the factory lines become clogged with rust and dirt. Cost me about $4.00 for the new lines. Good luck!!

[johnwaynejeep]

I have an 85 GW. I only have 2 lines running from the T-case to the switch in the cab. The plastic thing on the firewall where the lines mount before going to the T-case has 3 ports for vacuum though. I thought something was wrong but the PO used the 4 wheel drive all the time and I know he didn't do anything to it cause he's more mechanically iliterate then I am. Does anybody know if this 3rd line is supposed to be hooked up to anything. I've seen 3 or 4 more 85's and all of them only have 2 vacuum lines on the firewall not 3.