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Unread 06-17-2013, 06:09 PM   #1
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1989 YJ Wrangler 
Join Date: Feb 2012
Location: Borger, Texas
Posts: 5
4x4 trouble

soooo....was out doing a little wheeling lastnight and got stuck then i noticed my 4wd was engaged and the drive shaft was spinning and the "vacuum hose"? that comes off the axle was disconnected.. and i cant figure out where it goes is there a diagram online somewhere that i havent found that shows me where it connects to? its a 89 yj islander straight 6.. the driveshaft turns but nothing seems to be working i put a new carb on it got rid of the carter and put a motocraft 2150 on there and had a hard time finding a vacuum port that pulls enough from the carb to engage the accuator so its straight off the intake and its always engaged. and i think that might be some of the issue because its always engaged...which also hurt me driving down the highway at 70mph so this morning I messed with the actuator a bit this morning and now the 4wd works not sure if it was stuck or what but I still need to find a vacuum other than straight out of the manifold to connect to im sure someone else has had this problem thank ya!

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Unread 06-17-2013, 09:01 PM   #2
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1994 YJ Wrangler 
Join Date: Aug 2009
Location: Ripon, California
Posts: 19,228
Just lock the fork over.
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Unread 06-17-2013, 10:04 PM   #3
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1994 YJ Wrangler 
Join Date: Sep 2009
Location: dyersburg
Posts: 14
I'd go ahead an do the one piece axle swap just search it on here be worth it in the long run. Just my .02
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Unread 06-18-2013, 12:30 PM   #4
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1990 YJ Wrangler 
Join Date: Jun 2008
Location: st. louis
Posts: 1,268
It needs a check valve between the vacuum source and where it hooks up to keep the vacuum from being too low when you accelerate.

Here is a diagram of how it is set up. Stock, there is a vacuum reservoir, but I unhooked mine and it still works fine.

Note that the blue line is a vent. Also, be careful, there are some diagrams floating around (color homemade ones) that don't show the checkvalves correctly.

The vacuum lines are almost 25 years old if they are original. Probably should just replace them while you are messing with it. Regular autoparts store rubber ones are fine.

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