D30 vacuum actuator

okay, so its 5:30 AM and I get in my Jeep to drive at least 2 hours in a snow storm to go snowboarding, but I lose my 4wd. It ended up be the vacuum actuator motor. I have to hurry up and fix this before we get more snow up here so I can get back up to the mountains. I was looking a 4wheel drive hardware catalog and saw a posi-lok cable actuator that would eliminate al of the vacuum stuff. Has anyone installed this cable? If so, how easy was the install and how does it work? To replace the vacuum actuator it would be about $100 and the cable system is $200, if it does what its suppossed to, I wouldn't mind spending the extra $100.

Also, I know how everyone here like things bigger and better for the most part but please dont tell me to swap in a D44 or anything like that, I'm on a budget, when I'm done with school I'll ditch the D30.

Thanks,
Dean

swap in a D60 front...


No my bet would be its not the vac. actuator. have you tested it or anything when mine broke (going up rollover hill) it snapped the fork in half. Also if it is a necessity and you don't have a front locker just take a hose clamp and clamp the fork in the proper position. the only difference is that the front ds will spin all the time other than that you won't tell a difference in 2wd in 4wd it will be just like it is in 4wd. I can expalin in more detail if you need but I would first check the vac. accuator just find any vac. line on the engine and hook another vac line up to it and then put it on the actuator and see if the fork moves with any of them.
DIG IT!

Thanks

I do not know a ton about the system but I did know that something in there wasnt working. My father is a mechanic and knows all about how this stuff works so he'll be showing me.

I have the Posi-Loc system. Even tho it is pricey it is worth every nickel. Very heavy duty and well designed, easy to install. Either way....replace the aluminum fork with the cast iron one, it is available from Jeep.

Rev

more than likely your real problem is you have a cracked line (letting vacuum out)or perhaps its as simple as the connector has pulled off at the actuator. I manually control mine via two fuel tank selectors and it works extremely well. I switch it in and out probably 20 times per trail ride. I have had it this way for 3 years and have done many trails with no problems with the AL fork. I would rather have the cast iron one but I would bet the broken forks are often from weak vacuum that does not pull the fork over completly.

in a stock set up the vac goes from the motor to the t-case and then back to the axle actuator. thats a lot of places for those brittle lines to crack and a few connections to leak, before I used the fuel tank selectors it used to take some backing up and a little time for the fork to slide over, now its instantly in which ever position I put it in with my rocker switch, I put on the cupholder, couldn't be more convienent . the total cost for the solenoids and associated Ts and vac lines was about $50

After fighting rust in lines, broken lines, tc vac switches, etc...I got a Posi-loc
Like Rev Den, I found mine to be very well made and soundly engineered. Yes it was pricy...but i know i have front wheel when i need it most. The final straw for me with the stock system was getting stuck because the front would not lock in.

I am gonna try and make my own posi lock system I am gonna run a Toyota locker cable and handle to the stock actuator and put in a cast fork and then just seal it real good. I am also gonna weld the front gears. So this will help when turning on the trails.
DIG IT!

"more than likely your real problem is you have a cracked line (letting vacuum out)or perhaps its as simple as the connector has pulled off at the actuator."

I checked this out already, no vacuum leaks and the connector was still on there. The vacuum pressure does change when put into 4wd also. So the problem does lie in the actuator. I will take it apart and check it out.

How much does the cast fork run for from the dealer?

thanks

DDCxj said:

"more than likely your real problem is you have a cracked line (letting vacuum out)or perhaps its as simple as the connector has pulled off at the actuator."

I checked this out already, no vacuum leaks and the connector was still on there. The vacuum pressure does change when put into 4wd also. So the problem does lie in the actuator. I will take it apart and check it out.

How much does the cast fork run for from the dealer?

thanks

Click to expand...

I don't think the vacuum should change, except for maybe a momentary dip, when the actuator engages. It sounds like you have a vacuum leak.

If budget is really tight, you can remove the vacuum shift motor, engage it manually, shim it to stay that way with a bunch of flat wahsers, and put it back in the axle. It'll always be engaged after that, but Jeep stopped using the vacuum motor on the XJ after '90 so it's not like you really need it.

I did this; it costs less than $15

http://home.earthlink.net/~stevenschreiber/jeep/tech/cabledis.htm

It works great. Thank you to who ever you are that put your design on the web.

DaveWV said:

I did this; it costs less than $15

http://home.earthlink.net/~stevenschreiber/jeep/tech/cabledis.htm

It works great. Thank you to who ever you are that put your design on the web.

Click to expand...

Here's another (not my design):

Hmm.. I kind of liked the vacuum disco until a few days ago. After I swapped to 4,0 w/ AW4 and NP231 from the old 207 the vacuum switch wouldn't fit the transfer case properly, so I made a manual switch on the dash to control it, through the original vacuum stuff. However, the other day I got stuck in some mud and water and got pulled out. Later I found the vacuum plug on the actuator had fallen off. I put it back on, but after that the front axle would only engage once, and no more. After checking the connections and blowing trough a couple of vacuum hoses plugged with mud I also found that the diaphragm in the actuator was filled with muddy water. But it still didn't work, it seemed as if the vacuum was coming in the wrong hose... the leftmost on the actuator. It needs vacuum on the middle port to engage. I was going off road so I "hotwired" it to suck constantly on the middle port... still haven't figured it out. Maybe some of the "check" valves are dirty/clogged?

Forgetting why I started this post I'm just wondering if anyone has successfully troubleshot this system and have any clue about what's going wrong... ? Or do I have to toss it and install the cable? I think it's too expensive, being a student as well... didn't particularily like the bike wire patent either. But if the vacuum connector is going to keep falling off in the bottom of mud pits I might as well throw it away right now (it's fallen off once before as well)

Amund2 said:

But if the vacuum connector is going to keep falling off in the bottom of mud pits I might as well throw it away right now (it's fallen off once before as well)

Click to expand...

The vacuum connector that is falling off is the one that is coming off the axle end, right? I used a nylon ziptie that runs around the back of the vacuum motor and between the two vacuum lines that terminate at the double plug. Never had a problem, since. Sorry, no pictures, but it should be pretty simple, I was able to do it. :wave:

I really didn't like the bike bike cable in the first place either, but after e-mailing the guy who first did it and asking him how his was holding up, I went ahead and did it. I'm glad I did too. So is my bank account.

Once you actually see how simple the dissconnect mechanism is, you realize that making a cable system isn't all that hard. You don't have to use bike cable. You could use throttle cable off a mower or tractor or whatever. It doesn't need to be super strong.

I mountain bike and know that the brake and shifter cables can stretch enough that neither of them owrk. Has this happened to anyone using it to engage their front diff? If it has, what have you used to create more tension or does it not take much to engage it?

red87cherokee said:

The vacuum connector that is falling off is the one that is coming off the axle end, right? I used a nylon ziptie that runs around the back of the vacuum motor and between the two vacuum lines that terminate at the double plug. Never had a problem, since. Sorry, no pictures, but it should be pretty simple, I was able to do it. :wave:

Click to expand...

that should work, these are famous for falling off, i bought my 87 for $200, ran great interior was mint, but the 4 wheel was shot, i crawled under it, looked around, talked the guy down from 450, crawled back under, put the vaccum lines back on, and peeled away in 4 wheel drive through the snow..

look on his face priceless

i do plan on doing the cable actuator on mine one day as well, if i keep the dana 30,

DDCxj said:

I mountain bike and know that the brake and shifter cables can stretch enough that neither of them owrk. Has this happened to anyone using it to engage their front diff? If it has, what have you used to create more tension or does it not take much to engage it?

Click to expand...

I mountain bike too. Yeah they stretch, but you will NEVER put near that much pull on the cable using it in this way. Like I said, once you go in there and tear apart the dissconnect mechanism you will see that it won't take hardly any pressure to engage the front axle. Once the splines on the two piece axles line up the collar slides over effortlessly. The spring used is not that stiff. I could pretty much compress it with my thumb and for finger. The spring is only there to dissengage the axles.

The lever you use should have notches to keep the cable engaged in either position. There is not really any tension on the cable( except for the smaal amount from the spring.. For less than $15 it's definately worth the time and effort to know that the front axle will engage when I need it.

I like the cheap solution.

it looks like you have to pull the cable to engage the axle lock. so if the cable were to beak, the axle would be stuck in open position?

could the spring and the cable be switched so that it would fail in the locked position?

THanks

jjvande said:

I like the cheap solution.

it looks like you have to pull the cable to engage the axle lock. so if the cable were to beak, the axle would be stuck in open position?

could the spring and the cable be switched so that it would fail in the locked position?

THanks

Click to expand...

I guess you could mount the cable and spring on the passenger side of the dissconnect so that the spring pushed the fork over to engage and the cable pulls to disengage. You would have to do something with the the left overs of the old diaphram. Its worth looking into.

Dave