xj 4wd issues

[Will3161]

I've been having problems with my 4wd engaging; I did some troubleshooting, and here's what I've found:

1. First, the vacuum lines were disconnected. I checked them for vacuum, which they have, and I put them back, but they're really easy coming off. I though of using RTV on it, but I'd rather not. Anyone else do something with their's to keep them from coming off?

2. After reconnecting the vacuum lines, I get the part time 4wd light.

3. I know its going into 4-lo because the rear tires will turn against the parking brake and the front driveshaft turns as well. However, in 4-hi I'm not sure; the front driveshaft doesn't turn; is this normal?

So, any ideas? I'm pretty sure it is something in the axle, or more specifically the part that engages the axles. But, I don't want to pull anything apart until I've eliminated everything else.

 

[Seven]

What year and transmission?

 

[DOSS]

Pulling apart the engaging mechanism is no bid deal.. just 4 bolts.. clean it really good with some brake cleaner and then hook it up to the vacume and see if it actuates when vacume is applied.. if it does.. it should work.. if it is super slow or doesn't work.. it is dead.. 15 minutes of playing with it is all . Time spent cleaning this and making sure it is working is worth the time.. also make sure it is getting vacume. I belive there is a valve that turns on the Vacume that you may wish to check as well.. can't remember where it is as I have always just bypassed it and got rid of vacume disconect

 

[Will3161]

its a 1990 with the 4 speed auto/4.0 six. Interesting that you say there's a valve...I know I'm getting vacuum...but I wonder if it's enough? Do you know where the vacuum line draws from?

 

[DOSS]

its a 1990 with the 4 speed auto/4.0 six. Interesting that you say there's a valve...I know I'm getting vacuum...but I wonder if it's enough? Do you know where the vacuum line draws from?

Don't quote me on this but I believe that it is on the T-Case part of the selector. Someone who doesn't just put bolts in that Vacuum line may be able to speak to this more accurately... I will put $$ that the disconnect on the axle is either seriously gummed up or is not working though

 

[DaveB]

If it were my jeep I would ditch the disconnect axle and drop in a newer non-disconnect axle.

 

[Will3161]

I agree with changing axles, but money is an issue. (And I don't really have the facility the do any serious fab needed to change suspension mounts, etc.)

 

[DOSS]

I agree with changing axles, but money is an issue. (And I don't really have the facility the do any serious fab needed to change suspension mounts, etc.)

you could just get another D30 from a non disco year and just drop it in there...

Also you can just pull apart your vacuum disco actuator.. add some shimms (IE washers in there on the rod) so that it is always actuated.. then you no longer have to worry about the actuator failing on you.. or people used to make a mechanical actuator and there are some write ups on making it manual instead of vacuum.. I think it was on stu offroad?

 

[outlaw_offroad]

you could just get another D30 from a non disco year and just drop it in there...

Also you can just pull apart your vacuum disco actuator.. add some shimms (IE washers in there on the rod) so that it is always actuated.. then you no longer have to worry about the actuator failing on you.. or people used to make a mechanical actuator and there are some write ups on making it manual instead of vacuum.. I think it was on stu offroad?

You don't need anything but basic hand tools to swap out the shaft for a non-disconnect shaft. The housing is never removed from under the truck. The toughest part is pulling the carrier out of the center section. If you do swap shafts, by an axletube seal for at the carrier, this is not installed at the factory on disconnect axles.

If you are going to keep the disconnect shaft, install a 4x4 Posi-lock kit. They are around $100 and you will never have problems with your front axle again.

 

[Will3161]

I would like to do the posi lock, but with Christmas I'll have to wait a while. It sounds like the best compromise between manual hubs and what I have now. I'll look into the homemade one too. I read a little about it, but I think I need pull mine apart to see what it looks like up close. Concerning the shims, is that an easy quick fix that I could do for the moment and then switch to posi lock or something similar later?

 

[outlaw_offroad]

I would like to do the posi lock, but with Christmas I'll have to wait a while. It sounds like the best compromise between manual hubs and what I have now. I'll look into the homemade one too. I read a little about it, but I think I need pull mine apart to see what it looks like up close. Concerning the shims, is that an easy quick fix that I could do for the moment and then switch to posi lock or something similar later?

Shims are great and cheap, as long as the fork is in good condition. You need to inspect the fork for cracks. Also, another cheap option is using a jake-brake switch (vaccum switch) instead of the Posi-lock. You can buy them from a truck shop like Cummins for around $20.

 

[JoeT]

Shims are great and cheap, as long as the fork is in good condition. You need to inspect the fork for cracks. Also, another cheap option is using a jake-brake switch (vaccum switch) instead of the Posi-lock. You can buy them from a truck shop like Cummins for around $20.

Now you have my attention. Do you have any pics of one of these installed?

 

[90 cherokee]

i have a vaccume piece that works good you can have if you want it (broken fork) but if you want it pm me

 

[krany]

how did you check for vacuum?

 

[Will3161]

I had checked for vacuum by feeling it at the piece. Regardless, I've just shimmed the thing now. I probably wasn't getting enough vacuum, since I felt how much force was needed to actually move the fork. But, it works great now. I'm just gonna leave it like this unless I get a better front axle. Not the best for gas mileage, but that's not why I bought it anyway.

 

[krany]

say hello to posi-lok
http://www.4x4posi-lok.com/app_jeep.html
you should need part #920 if your lifted- better to get even if your not lifted since you never know what may happen in the future:greg: