4 wheel drive not engaging

[trooperdog]

I have a 1990 Jeep Wrangler YJ 4 x 4 and when I try to engage it, only the back wheels will engage, the front ones will not. Any ideas or suggestions?

 

[J.C.]

Possible vacuum leak going to the front disconnect mechanism? Small plastic vacuum line is notorious for breaking/leaking.

 

[rustyolred]

x2 on the front vac leak.

 

[userbmx1315]

read follow and enjoy. it'll take care of it.

http://www.jeepforum.com/forum/showthread.php?t=595515

 

[fishgutz]

Leaking Vac? Excuse for upgrade

This happened to me on a trail ride.
Had to remove the fork, jack up the axle so the wheel could move and align the collar. Flip the fork and remove the vacuum line in case it miraculously healed.
When I got home I ordered a set of chromo axle shaft upgrade.
Mine for about $450 plus shipping. Now my D30 front can easily handle 35's or 37's.
Superior sells a kit with the u-joints already installed for about $100 more.
Or you can do the cable actuator for $225.

 

[89wrangler]

Just slap a set of D44's in there before you waiste any money on the D30/D35 as they are cheap and almost a bolt in. But as they said, Vacum. The switch is on the top left side of the Tcase. Check the axle end first, probably just pull off the vacum port.

 

[buckshot500]

Plastic vacuum lines

The plastic vacuum lines used, are resistant to all automotive fluids!





Except battery acid.


Why did they run them under the battery tray???

 

[lbyota85]

Now my D30 front can easily handle 35's or 37's.