I have been wanting to do this now for a while. I have had crazy handling on my jeep, very scary.
Just some background and things to check first:
1. I found a lot of play in my trackbar bushings. So I purchased KOR durometer bushings, that tightened things up a bit.
2. I installed KORs steering brace, didnt notice a difference, but it minimized a clunk noise I had when turning my steering wheel.
3. Replaced a bad Tie rod end at the pitman arm, also reduced clunking, steering did not improve.
4. all other front end components are tight and new (bjs, control arm bushings...etc)
5. 2 alignments by two different shops, last one resulting in poor pinion angle causing front ds vibes. And my steering performance did not change.
So before I dropped the money for a brand new steering box, I decided to adjust mine, the proper way.
The first adjustment is to bearing preload, second is the over center adjustment.
1. People say this can be done with the box in the jeep... I cant imagine how it is done. Best to remove the thing, otherwise you will make a 2 hour job = 5 hours.
2. Remove the steering box from the jeep, if you have KOR brace remove that too because the box wont have enough clearance to drop with the brace in place. I couldnt get my hands down to the box to remove the pump lines, so I removed the lines at the pump instead of the box. Here it is out.
3. This end here is the stub shaft, it is where the steering column attaches to the box.
remove the lock nut to the adjuster by using a punch and a hammer,
4. now take your wrench, I only had 90 degree needle nose pliers, and turn the adjuster clockwise
until it is fully seated in the housing
5. Take a ruler and make an index mark at an adjuster hole, then measure .5 inches or 13 mm in the counterclockwise
direction and make a second index mark
6. now turn you adjuster hole so that it is positioned/line up to the second index mark!
7. Put the lock nut back on the housing and tighten the crap out of it. BE SURE THAT THE ADJUSTER DOES NOT TURN DURING THE INSTALL OF THE LOCK NUT!!!
8. The next part requires that you find the center of the gear range, you have to turn the stub shaft...I found this rather difficult, so I took a 19mm socket, and folded up a rag, I pressed
the socket over the rag onto the stub shaft, and it made a nice snug fit so that I could turn the thing with my wrench! This also allowed me to put my torque wrench on there to measure rotational resistance/torque.
8.a. Turn the stub shaft all the way to the end of its travel. Now turn it back in the opposite direction counting the number of turns (should be 3 and a 1/4ish turns) Now turn the shaft once again in the opposite direction for half
of the turns counted in previous step. This will be the CENTER of the range!!
9. Loosen the center drag lock nut and turn the adjusting nut counterclockwise
until it can turn NO MORE. Now turn the adjuster clockwise
one full turn.
10. Put your tourqe wrench on the stub shaft and measure the highest rotational torque. Start your wrench in the vertical position and turn left to right to only 9 oclock then reverse to 3 oclock. Record the highest torque.
11. now turn your adjusting nut a little clockwise
and remeasure the rotational torque of the stub shaft. Your goal is to get the shaft torque 6-10 in/lbs higher than the base reading measured in step 10.
12. after you have adjusted your center drag, put the lock nut back onto the adjuster and tighten to 20-36 ft/lbs (the FSM gives two specs for this torque, both 20 and 36. so pick one) Be sure that when you tighten your lock nut the adjuster does not turn!! I used my allen inside my socket to make the nut as tight as I could with my hands and pliers. Then I was able to torque the lock nut.
13. Install the box back into the jeep. Have fun!!
Some Special considerations:
1. Drain the box! I didnt and I made a mess, and the fluid builds pressure and you get resistance when turning the stub shaft, this can lead to bad torque measurements.
2. Get a helper to help you hold the bearing preload adjuster when you tighten the lock nut. That thing will turn when you tighten the lock nut.
3. it doesnt take much on the center drag adjuster to increase the rotational torque by 6-10 in/lbs. I think my adjustment ended up being about 1/4 of a turn.
4. Hold your allen wrench when measuring rotational torque on the center drag adjustment. I found that by turning the stub shaft with the center adjuster lock nut off, the adjuster was also turning. So I had to hold the adjuster while measuring torque.
Gearbox to frame bolts: 65 ft/lbs
Pitman arm nut: 185 ft/lbs
Additional input from NewfieZJ
FSM VS TSB
Just recently did a bearing preload on a box I had kicking around , it's still on the bench But yesturday , decided to try a preload on the MJ I have before swapping boxes , while it was still in the truck .
Going by memory of the TSB , I marked it only 9mm , instead of 13mm . I'm also pretty sure it moved down to 8 after it was tightened . Worked like a charm , hell , I am not changing the box after all , lol .
So that was all well and good . I began to reread some threads on here and reread your write-up , and also the tsb vs fsm thread .
I can certainly agree with the fact this was for a dodge Ram , not a jeep . What I will say is that because of this steering box TSB , I got curious .
All ZJ FSMs up to 1997(printed prior to the TSB) most certainly spec'd 13mm or .5" . however , this is where it gets interesting , the 98 speds 10mm .
Personally , I do think the info was updated , probably never made it to online accessability like the Rams and instead of 13mm , it was updated to 10mm and made print for the 98 model year FSM .
Either way , it's going to be alot tighter than it was before , does the 3-4 mm really matter ? Doubt it