Steering Box Input Seal Replacement
Earlier this year my Jeep started acting rather naughty and began noticeably marking it's territory. A 4.0 leaking oil is nothing out of the ordinary, but in this case, the leak was much farther forward than where the usual engine leaks would show up. For me it was my steering gear box, and it appeared to be leaking pretty good from the input seal at the top of the box.
This was a bit inconvenient as I had a camping trip planned and wanted to get this fixed up prior to that. The rebuilt boxes that you can get from the usual parts stores tend to be sloppy and leak, and new ones were upwards of $500+. My steering box was in good shape other than the leak, with no slop at the pitman shaft, and there were no dead-zones in the steering. I have experience rebuilding the steering box for a friends 87 XJ so I figured this was the route that I'd go. However, due to my time constraints, I chose to just replace the offending seal and not rebuild the entire box at this time. If I need to take it back out later on down the road it isn't a big deal, and not too difficult of a job.
To start out I figured I'd begin with the most dreaded part, removing the pitman arm. I loosened up the pitman arm nut with my impact, but left it screwed on a bit in order to catch the arm when it pops free. My box had a black rubber boot on the pitman arm shaft which had popped out over time; I made sure to push it back up into the box before I used the pitman arm puller.
Now it was time to have some fun! I had a couple
Harbor Freight tie-rod/pitman arm pullers laying around that I could torture. I tried being civil with the first one by tightening it with a ratchet and beating on the pitman arm with a BFH. That didn't work at all, and just ended up bending the puller and ovaling out the threaded hole on the puller.
I busted out the second puller, and this time I planned on not being so nice; I put a c-clamp over the open end of the puller to try and prevent it from spreading open. I grabbed my big impact and gave the puller full beans until it started to spread open. I gave the pitman arm a few BHF whacks but still no luck. Using the impact I sent a few more ugga duggas into the puller, and right before the puller was about to spread apart too far, the pitman arm popped free!
I removed the fluid from the reservoir using an
OEM tools fluid extractor, afterwards I setup a jack underneath the box to support it as I remove the bolts. I also had to disconnect my SwayLoc links and swing the arms out of the way, the driver-side arm obscures the steering box bolts. With that done I used my impact to remove the steering box bolts, all 3 came out with no issues.
I lowered the jack a bit to give me better access to the power steering lines as well as the steering shaft bolt. I removed the bolt on the collar of the steering shaft and used a pry-bar between it and the box to pop it loose. The lines are easily removed with an 18mm wrench; I didn't have a flare wrench that size but a normal open end worked fine. Once the lines are removed the box was free.
Before starting on the seal replacement I took a rotating preload measurement on the input shaft with my beam-style torque wrench, similar to differential pinions. I neglected to take any pictures but the FSM covers the procedure, called the "over-center adjustment", and it's quite easy to do. In a nut shell you make sure the pitman shaft is centered and then you measure the rotating torque on the input shaft 45* in either direction. In my case the box came in at about 10 in/lbs of rotating torque.
Now the disassembly can begin. The locknut on the outside of the input shaft preload adjuster is the first thing to be removed. I've seen them in different shapes, but they all have notches on the outside edge where you can fit a punch and tap it until it's free.
With the lock ring removed I then scribed a mark aligned with one of the holes on the adjuster nut. This mark, as well as the preload measurement I previously took, will help me ensure everything is put back together correctly in the end.
A special tool is required at this point, it is a large pin spanner used to remove/tighten the adjusting nut. I easily fabricated one using some 3/16" steel stock and grade 8 bolts that fit the pin holes.
The adjuster nut can now be removed with the spanner. The FSM and few guides I found made this step seem easy, and perhaps it is for most situations, but this box wasn't going to give up without a fight. I fought with it for a while on my bench in a vise, but I realized I could mount the box upside-down in the frame to really get good leverage on it. It took a serious amount of force, even bending my tool a couple times, before the nut finally gave up and broke free. Once I spun the nut all the way out it was pretty obvious why it fought so hard: years of crud accumulation had caused lots of rust and corrosion.
The input shaft should now be able to be wiggled free with a little bit of effort. Mine did not want to budge, and I figured it was likely due to the crud and rust. I did lots of cleaning and spraying with penetrating oils and WD40, even using some heat, but the thing just did not budge. Eventually I resorted to putting it back into the frame and tried using the input shaft itself to push the seal/bearing assembly free. It took a lot of force but it finally did break free and move a little. I brought it back to the bench and removed the whole assembly. It is important to not turn the input shaft much past the point where it pushes the assembly free, as that will unleash all of the input-shaft ball screw bearings inside the box.
The input bearing assembly pulls away from the input shaft and valve body
I inspected the input shaft where the seal rides for any grooving and polished it up a bit with some 400 grit and then 600 grit sand paper.
The input shaft seal itself is in the top of the bearing assembly and is easily removed with a seal puller. There is also an o-ring on the outside of the bearing assembly that needs to be removed.
I spent some time cleaning up all of the parts, including sanding and polishing up as much of the rust that I found earlier; this will help decrease the chance of damaging the o-ring upon installation. I dug through my rebuild kit and located the new parts, using my old parts for reference. The kit I ended up using was a
Gates 349630 Power Steering Repair Kit
I drove the new seal into the bearing assembly and applied some grease to the seal lip. Then I soaked the o-ring in power steering fluid and put it into it's groove on the outside of the bearing assembly. I poured a bit of power steering fluid into the bearings and then slid the assembly back onto the input shaft. I put some tape over the splines to protect the new seal during install.
The assembly must be aligned with two tangs and a pin that are located inside the box on the worm-screw shaft. I pushed down until the assembly was fully seated.
Due to all the rust discovered during my disassembly I chose to slather all surfaces between the input bearing assembly, adjuster nut, and threads of the box with lots of anti-seize. The adjuster nut was then screwed down until the mark I made previously lined up properly. I tested to make sure that the rotating preload was in spec and everything checked out.
I put a bit more anti-seize onto the outer threads of the adjuster nut and then threaded on the lock-ring. While holding the adjuster nut steady with the spanner I punched the lock-ring in a similar fashion to how it was removed until it was snug.
The box was now finished up, I got it back under the Jeep and reattached the lines and steering shaft. The steering box bolts had blue LocTite applied to them and were torqued to 70 ft/lbs. I applied some anti-size to the pitman arm splines and slipped it on as well as it's nut and lock-washer. The pitman arm nut was torqued to 185 ft/lbs.
I filled the power steering reservoir up with fresh fluid, hopped into the Jeep, and turned the steering wheel lock to lock a few times. I topped the reservoir back up and then fired up the TJ and repeated the process until the level was stable. I took it for a drive around the block, trying to make as many turns as possible to work the system good. Everything felt as good as before the repair, and after getting back and inspecting, there were no leaks! This repair has been a success, and still has no leaks several months later.