Megajolt Ignition Upgrade
Valve Guide Seal

Warning and Disclaimer

The correct rebuilding of a steering box is obviously of critical importance to the safe operation of any vehicle. Safety first always! Utmost care must be taken to do this job correctly.

DO NOT attempt this rebuild unless you know what you are doing! This is a job only for the professional. We are not responsible in any way for work done on any vehicle.

The information here is simply a record of what we did and not instructions for anyone else to follow. All steering system maintenance and modification must be carried out by qualified professionals.

Saginaw Steering Box "Rebuild"

This "rebuild" does not change the major wearing surfaces inside the box but rather installs new bearings and seals. If the surfaces of the 'teeth' on the sector shaft or the worm or internal piston are worn or damaged, a new box is required. The rebuild kit provides the necessary parts for a "freshen up".

The rebuild kit for this job came from West Texas Offroad <www.westtexasoffroad.com>

I phoned West Texas and was informed that there are several kits available for different variants on this perennial box. After talking with them it was possible to determine which version of Saginaw box we had and therefore to order the correct kit!

Definitive instructions for this job came from Four Wheeler magazine, January 2008. The technical article is available online.

Exchange rebuilt steering box are available for about $200-300, which is cheap. The rebuild kit cost over $50 alone and this work took many hours to perform. New Saginaw boxes are available from AGR and Borgeson - a new box will always be the best solution when your old box is worn out.

Saginaw Steering Box Disassembly

Step 1A

Thoroughly cleaned with Varsol and a tooth brush, the 1980 Cherokee box sits in an expendable aluminum tray. The box is a three bolt, metric hose end version.

The casting is #7826697. The top cover little rectangle is stamped OB over 88.

Note that the hose ports have been plugged - do not allow any dirt to enter these ports.

Also, more importantly, do not be tempted to 'borrow' a good tray from your wife's kitchen. You will surely regret it. Likewise, do not attempt to return the toothbrush to your mother-in-law's bathroom...

Step 1B

The front plug casting number is 568910

The pitman arm (no drop) is from a Chevy Astrovan

Step 2

Remove the pitman arm securing nut - nothing beats the correct tools - in this case an old Workmate and 3/4 inch drive ratchet.

Step 3

Before pulling the pitman arm, mark the relative position of the shaft with a punch. Although not really necessary in this case, it avoids any possible confusion.

Step 4

Use a pitman arm puller. Once under tension, a light tap with your ball peen hammer and off she comes. These Chinese-made pullers are cheap ($12) and work fine.

Step 5

Next, the C-clip must be removed. My cheapie set of pliers is only just up to the task! I must invest in a good set of circlip pliers one day.

Step 6

Now remove the four 9/16" bolts from the top cover of the box.

Step 7

If you turn the input shaft back and forth as you remove the sector shaft, it will come out easily. Lots of fluid will escape.

Step 8A

Now you can examine the shaft for damage. Ours looked like new except for some light corrosion.

Step 8B

Here is the 29 year old bearing - it also seemed to have very little obvious wear. I am already impressed by the Saginaw design and longevity.

Step 8C

You can now see the piston inside with its "teeth".

Step 9A

Use a probe or punch to push down on the strong retaining ring from above. The engineers kindly provided an access hole for you. The heavy steel ring needs to be worked out of its slot in the casting - it's wise to clamp the box in a workmate for this operation - I didn't...

Step 9B

Almost out.

Step 10

If you rotate the input shaft, you will push out the plug without trouble.

Step 11A

As you continue to turn the input shaft, the piston will escape from the casting bore and disgorge it's steel ball bearings... catch them! Even more fluid will dribble out.

Step 11B

Here is the piston with its strange bearing guide held by a strap and two bolts. There are supposed to be 26 ball bearings but I only found 24.

Teflon seals and O-ring must be replaced.

Step 12

At the other end of the box, remove the C-clip from the input shaft end.

Step 13

Remove the outer locking ring using a soft drift (I used a snubbed spike). When I tapped on the locking ring, it would not move, so I used...

Step 14

My homemade tool fits into two holes in the so-called adjuster plug. The adjuster plug with locking ring unscrewed together.

Step 15A

The adjuster plug and attached inner worm can now be pulled out.

Step 15B

Here you can see the assembly as removed. This method, of pulling the unit out vertically, was very unwise as the worm could have fallen off and been damaged.

Step 15C

Inspect the worm carefully for scoring or burrs. Teflon seals and O-rings must be replaced.

Step 15D

Here you can see the end float bearing that locates the worm when the adjuster plug is screwed inwards.

Strangely, our rebuild kit did not include a replacement for this bearing.

Now the final task in disassembly:

Step 16

Find a 1/2" drive socket and extension to drive out the sector shaft bearing and two oil seals. Make absolutely sure the socket is small enough to move into the bore but big enough to mate with the outer race of the bearing. No damage please, you don't want to score the piston bore!

Drive out the bearing and two oil seals with their washers.

Step 17

Exploded view of the disassembled box.

Put all the parts in a box so there is no chance for anything disappearing. Again, I found 24 ball bearings.

Saginaw Steering Box Reassembly

Step 18

First, prise out the dust seal and oil seal from the adjuster plug. Then tap out the old bearing using an appropriately sized socket.

Step 19

In goes the new bearing. It is better to put the adjuster plug down on the workbench!

Step 20

Take time to carefully clean the thread on the plug

Step 21

With the new oil seal and dust seal in place, the new C-clip is installed.

Step 22

Oh yes, of course, clean off that surface rust a bit!

Did I push in the dust seal too far?

Step 23

Remove the 3 old teflon rings using a small probe. Other than being discoloured, they were in good condition.

Be very careful not to stretch or otherwise damage the new rings as you install them. They have a square profile (as opposed to the round profile of an O-ring) and must be properly seated.

Step 24A

Change the O-ring and slide the lubricated stub shaft into the adjuster plug. A little power steering fluid will make everything slide together better...

Step 24B

The unit with new seals is ready for installation.

Step 25

The worm has two tangs and one locator dowel for correct alignment in the stub shaft assembly. Don't forget the new thin O-ring.

Step 26

Here you can see the worm and stubshaft offered to the box housing. The old bearing and its landing are reused.

Step 27

The homemade tool is used to screw in the adjuster plug of the stubshaft into the housing. The plug is screwed in until it bottoms and is snug, then unscrew it a little bit (about 15-20 degrees?)

Step 28A

Use of a bronze drift would be best to tighten the locking ring on the adjuster plug but I used a piece of scrap walnut. Stop the adjuster plug from turning during this process.

Note the mistake! I am installing the locking ring backwards.

Step 28B

Now you can see the worm in place inside the casting. Clean away the unwanted paint.

Step 29

Although it is not yet time to install the sector shaft, take the time to clean up any corrosion on the bearing surface. A little #600 emery paper will do the trick. Also clean the pitman arm splines and threads at the bottom of the sector shaft.

Step 30A

Here you can see the difference between the old sector shaft bearing with its shoulder and the new one on the left. Obviously, without the shoulder, the new bearing can be pressed in 'too far'.

Step 30B

Here we go. A useful old trick is to use a suitably sized socket mounted backwards - makes a nice 'drift' to install the new bearing. Again, a little power steering fluid will work as a lubricant.

Step 31

Install the pair of oil seals and the two washers. Note that the thicker oil seal has a double internal pair of sealing lips - it is installed on the outside.

Step 32

The C-clip finishes this part of the job.

Again, did I press in the oil seals too far?

Step 33A

Here is the disassembled piston with its new teflon ring and O-ring.

You can see the 24 steel balls and the strange ball bearing guide in two halves. Also, the clip and two short 3/8" bolts that secure it to the piston. Apparently some Saginaw steering boxes have 26 balls and others may have two ball sizes. With two sizes, you install them alternating big and small.

Step 33B

Somehow you have to keep the balls inside the piston while you insert it into the housing.

Pack the bearing guide halves with grease and press in 9 of the balls. Install the bearing guide and then press the remaining balls into grease along the inner machined spiral of the piston. Keep the all balls in the spiral between the holes that the bearing guide limits. This is not easy - a magnet on the end of a probe will help or get someone with thin fingers to help! Your Lady will forgive you eventually.

This is the defining moment of the assembly.

Step 34

Very slowly lower the steering box so that the worm enters the piston sitting upright on your bench. It is critical that you turn the input shaft as the piston threads over the worm - with the ball bearings inside. If you are careful and lucky, the process will work so that the 24 balls end up between the worm and piston internal spiral surfaces. Try to start with the worm clocked exactly right so it begins its entry into the piston ready to mesh with the first ball - easy to say but not so easy to do...

Note: it helps to have a U-joint attached to the input shaft so that it is much easier to turn. A pair of visegrips will do of course.

Unless you are Superman, it will not be possible to really know if all the balls remain in place at this point.

Step 35

Next, install the front plug at the big end of the bore. Don't simply try to tap it into place with its new O-ring on the plug.

First scrape off any paint that might impede the plug's entry. Then, grease the seat where the plug O-ring sits in the box. Also grease the recess around the plug where the O-ring will sit. Install the O-ring in the box and then, using a rubber mallet, tap the plug into place. It will resist seating and then finally will snap into place.

Install the new strong steel retaining spring - make sure the 'beginning' of the ring is near the hole in the housing or the next pup who must remove the plug will curse you! The next pup just might be you...

Step 36A

Here is the piston aligned in the box so that the three 'teeth' are above the sector shaft bearing. It is essential that the piston is rotated so that the teeth are vertical - parallel to the axis of the sector shaft.

Grease the 'teeth' of the piston and the sector shaft.

Step 36B

Here is the sector shaft and its cover ready to install. The cover gets a new copper/rubber gasket - two little tabs, bent up over the cover, hold it in place.

I did not remove the top cover from the sector shaft and replace its bearing as it was clearly in excellent condition. The kit contains the bearing and new nylon (locktight) nut but they were not used.

If I had replaced the bearing inside, I would have had to readjust the freeplay on the sector shaft after assembly. To do this, use an Allen key and wrench. Turn the Allen key until there is a little resistance half way between steering extremes - the mid point - and then back off a little bit (perhaps 15-20 degrees)

Step 37

The finished job with pitman arm reattached, ready for vehicle installation again.

Step 38

One minor problem: the exact position of the oil seals above the pitman arm and along the input steering shaft are not absolutely determined. Did I press them in a bit too far?

The probe here shows that the bottom oil seal is not touching the limiting C-clip.

Final word: after rebuilding our 29 year old Saginaw steering box it was clear that there was almost nothing wrong with it. We clearly could have changed the oil and dust seals to stop leakage and left the internals untouched. Live and learn.