4wd

Go topless 87

New member
Hey I've got an 87 and when I put it in 4wd the front shaft goes around but the front wheels don't go around. Any idea what's wrong wit it. I've got vacum operated 4wd. Any idea?
 

make sure all the vacume stuff is still connected.
 
make sure all the vacume stuff is still connected.
check under your battery for a possible hole in your vacume line,what has been known to happen is that the acid from your battery gets on the hose and eats a hole in it. If I was you I would get the posi loc system,and do away with the vacume system. It is a cable that runs from inside your jeep to the actuator that engages your 4 wheel drive. Which is located on the passanger side of your jeep,on the back side of your axle.It is a small square box. Inside that box is a fork that slides a ring that engages your front axle,that may aalso be the origen of your problem,the fork could be wore out,and not able to slide the ring to engage the front . Quadra tec has the posi loc. Good luck.
 

man i had that posi lock and i hated it. it didnt work much better. i finally put tj shafts in and wish i wouldve done that to begin with. it was cheaper to convert to tj shafts than to get the posi lock and its a hell of a lot better.
 
I changed all those horrible plastic lines for rubber lines and haven't had a problem since. Bought 20' of line and laid under there and changed it all out, from the engine to the transfer case to the axle.
 
It is an easy fix. It requires troubleshooting though, not internet questioning and geussing. It is most likely a failed vacuum line which is almost no time to fix
 

I had a new YJ, tan, in 1990. I and my new bride (deceased) took off from NASA-KSC in Forida, up to Montana, my folks place. No probs. After 4 months, I developed so much vacuum issues and the issues with the 2nd gen SSI (Solid State Ignition-Computer) and finally, sent the Jeep to auction in Spokane.

No more of that.

So, trace out the lines, test for leaks, then, strip out the whole mess and go with a used points and condenser Iginition for about $50 and call it good....

Just a thought,

Robert
 
to put in tj axles you need to get a different seal thats the same diameter of the tj shaft. the short side goes in with no changes but the disconnect side is way bigger so the old seal wont work. i just took all that disconnect crap off and put the collar where it is engaged all the time and put 2 big tywraps on each side to hold it in place and its been working fine for 7 or 8 months now and only cost 50cents. no seal replacement either. my buddy has had his like that for 2 years with no problem.
 
a problem i noticed with a locked front end is sometimes you get some vibration from the driveshaft turning all the time. i am not sure if the shaft was bent or what but on the wife's 93, that was an issue when the collar was in the locked position all hte time
 

a problem i noticed with a locked front end is sometimes you get some vibration from the driveshaft turning all the time. i am not sure if the shaft was bent or what but on the wife's 93, that was an issue when the collar was in the locked position all hte time

Something is bent or you have a U-joint fail. VEX and all other Jeeps when things are sound and hubs in, especially if you have CV joints at the TC, should ride and drive as smooth as a car at all speeds.

Robert
 
You can also remove the disconnect from the axle, engage the shift collar, and reinstall the disconnect upside down. The shift fork will now hold the shift collar engaged. It's safe to run like this all the time.
 

I suggested the posi loc cause actually I dont know much better,I bought my jeep with the posi loc already on it.after joining this forum,I came to believe that it is a better set up then the vacum system. When I started useing the posi loc I wasn't to impressed with the way it engauged,and thought there has got to be a better way,but havent done any research in that area yet . When permanetly locking in the front end with the drive shaft turning,wouldnt that effect power and mpg,espically for a 4 cyl,which is what I have.
 
yea mine had some vibration when i first did it but i changed the ujoints and is smooth riding now. and when you on the street your in 2 wheel (hopefully anyway) so the front is just spinning its not taking any power from the motor. i didnt notice a change in mpg.
 

I suggested the posi loc cause actually I dont know much better,I bought my jeep with the posi loc already on it.after joining this forum,I came to believe that it is a better set up then the vacum system. When I started useing the posi loc I wasn't to impressed with the way it engauged,and thought there has got to be a better way,but havent done any research in that area yet . When permanetly locking in the front end with the drive shaft turning,wouldnt that effect power and mpg,espically for a 4 cyl,which is what I have.

I run TJ alloy axles up front, which means my front DS is always turning. No issues with power loss and mpg have come up yet (over 2 years), and I drive a 600 mile roadtrip every 3 months (from Panama City, Panama to San Jose, Costa Rica).
 
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