Rebuild and Assembly
For rebuild, I will start with the ball screw and gear piston assembly. If you were unfortunate enough to remove the ball screw from the gear piston (as we did) you have likely found how it works. The machined groove of the ball screw engages with 10-15 precision ground bearing balls. Some mechanical slop in the steering box could be due to wear of the balls. On a future rebuild, I will measure them to confirm size for replacement (mcmaster has tons of sizes and tolerances available).
To re-assemble the ball screw and gear piston, first remove the 2 bolts that fasten the transfer tube to the top of the gear piston (sorry, no photo). Remove the tube and separate it into its two sections. Insert the ball screw into the gear piston. Proceed by dropping balls into the holes in the top of the gear piston until the ball screw track has been filled. Place the remaining balls into half of the transfer tube. Place the other half of the tube over the balls, and quickly insert the tube into the gear piston. It may take a few tries. Once installed, re-install the two bolts the fasten down the tube.
Now with the ball screw and gear piston re-assembled, you can install the new seals. The assembly uses 5 square cut seal rings on the power steering portion of the ball screw, and one more on the gear piston with a backing o-seal.
On the gear piston, remove the original seal and o-ring and install the blue o-ring and pink square seal ring provided in the kit
For the balls screw, remove the 5 original seals. To ease installation of the new seals, we removed the snap ring and retaining rings as the top of the assembly. It may not be necessary, but it made it easier for us. Be careful as there are small parts.
Remove the snap ring to access the two torx screws. Remove the two torx screw, then using pliers remove the retaining ring, pins, and blocks.
To install the seals, we gently heat them with a heat gun and carefully stretched them over each seal gland, making sure not to twist or cut the seal. Take care not to over stretch the seals.
Once all 5 seals are in place, re-assemble the retaining ring, torx screws, and snap ring if removed. Take note not to over tighten the torx screws.
With the ball screw and gear piston set aside, begin to remove the original bearings as seals from the housing. First, remove the sector shaft seal wiper from the bottom of the housing. Under the wiper will be a snap ring and retaining washer.
Remove the snap ring and washer.
With the snap ring removed, using a long punch or driver, tap the lower sector shaft bearing and sector shaft seal out of the housing.
Flip the housing, and from the other end using a long punch or driver, tap the upper sector shaft bearing out of the housing.
With that, the steering box housing should be fully disassembled and ready for new seals and bearings. Take the time now to clean the entire housing with brake cleaner. Also, if planning to port and tap the steering box for hydro assist, now would be the time as it can be thoroughly cleaned after.
To rebuild the housing, using a bearing driver, drive the new upper sector shaft bearing in from the top of the housing.
Using a bearing driver, now drive the new lower sector shaft bearing in from the bottom of the housing.
Next install the new sector shaft seal. You will likely need to use a seal/bearing driver to seat it. Take note to install the spring side of the seal inboard of the housing. These are directional seals, and will leak under pressure if backwards. Yes. We messed this up. Below shows the seal in backwards:
Next install the washer and snap ring in the housing.
Finally, install the sector shaft wiper seal using a bearing/seal driver. Make sure the wiper is facing outboard of the housing.
Returning to the ball screw, lubricate all 5 seals with ATF and carefully slide the gear piston and ball screw back into the housing, making sure that the gear piston is square to the sector shaft cavity. You may need to turn the ball screw a bit to force the piton into the housing further, into a more central location so that it easily aligns with the sector shaft.
Re-install the large snap ring holding the ball screw into the housing.
To rebuild the power steering block, first, drive the input shaft bearing out of the housing with a large surface punch. This bearing is not replaced in the kit, so take extra care when removing it. Drive it away from the seal with the punch. You can see the disk-shaped rollers under the seal in the below photo:
With the bearing removed, drive the seal out of the housing the same direction.
Install the new seal first, ensuring that the wiper is out, and spring side (shown) is facing into the block.
Re-install the original input shaft bearing as shown, with the larger majority of the disk-rollers showing when viewed form the inside.
Side that goes against the seal:
Once the seal and bearing are installed, replace the OD seal on the power steering block with one of the black o-rings.
Replace the face seal on the power steering block with the provided small o-ring.
Lubricate the OD seal with some ATF, and gently re-install the power steering block to the housing. Install and tighten the 3 housing bolts.
Finally, remove the original OD seal from the sector shaft cover, and install the provided replacement seal.
Lubricate the OD seal and gently slide the sector shaft and sector shaft cover into the housing, making not to properly align the gears. Re-install and tighten the 4 cover bolts.
Remove the sector shaft adjustment nut without adjusting the bolt, and install the new nut. Verify that the gear backlash is set correctly by following the setup instructions listed in the FSM, discussed Adjusting steering box???
And you're done. Hope that helps someone out there. I will try to update once I get some more measurements of some of the different sup parts, and take a stab at a China box. Hopefully more to come.