How To Rebuild Your Saginaw ZJ Steering Gear
This is the second part to my Saginaw 800 series steering gear rebuild how to. With information on rebuilding the Saginaw steering gear being very vague, incomplete and hard to find. I'm hoping this how to will aid the backyard mechanic with the proper tools to successfully service their Saginaw steering gear. To aid in the assembly you will see I fashioned a board that attached to the mount holes of the steering gear so i didn't have to place the gear in the vice after i had painted it, yes I'm anal about those things along with keeping parts clean prior and during assembly too.
If your attempting to service your Saginaw steering gear and encounter worn out components, DO NOT REUSE THEM!!!, obtain replacement parts that are good and use them instead, or use a JY box and rebuild it instead!!!, throwing bad parts at a good project will only yield bad results!!!
Now on to the fun part!!!!
With the tear down complete I started in on the cleanup of the various parts and further inspected them for any damage, I couldn't find any with the exception of some minor grooving from the old seals on the sector/pitman shaft of which i sanded down most of it being very careful not to touch the needle bearing surface, i was able to eliminate 95% of the double lip seal groove and about 75% of the single lip dust seal groove, enough to not damage the new seals.
I glass bead blasted the steering gear housing in preparation of painting it.
I made certain not to blast any of the critical internal sealing or hydraulic surfaces. After masking all surfaces i didn't want painted i always do a little trick that has worked extremely well over the years and this is to use a propane or map gas torch to heat the metal up to evaporate any moisture that is resident in the metal, yes metal can soak moisture in and is huge cause of paint work bubbling up due to rust!. After its cooled off i proceeded to shooting the primer and color on.
I received the rebuild kit and laid out all the o-rings, seals, Teflon rings and related hardware in preparation for rebuilding.
A side note..... check all your rubber parts for softness as you lay out the parts, some have reported getting defective rubber O-rings that were very hard and or brittle.
Some of the assorted tools ill be using in the rebuild.
Let the rebuild begin!!!!!
First thing to do is press in the sector/pitman shaft bearing. (NOTE*) the lip side is up and the bearing is pressed from the bottom side of the steering gear housing as shown.
Using a bearing and seal installer i pressed the bearing into its bore.
When the bearing is seated all the way you will hear a distinct ringing thump. Inspect the bearing to make certain it in all the way.
Next is the sector/pitman shaft pressure seal and nylon washer, press it in till its seated against the bearing, this will take a bit of pressing and inspecting often to make certain its seated all the way as you are pressing reinforced rubber in and without prior experience can not tell easily if its in all the way. (NOTE*) this seal is thicker then the single lip dust seal!!!.
Drop in the spacer washer.
Install the retaining ring with snap ring pliers.
Confirming its completely in its groove, and it is.
Press in the single lip dust seal.
Confirm its all seated in properly.
Next step is to install the o-ring on the spool valve, its the smallest o-ring in the kit.
Installing the three o-rings on the valve body.
Install the three Teflon rings OVER the three o-rings on the valve body, the purpose of this is to provide a flexible backing to the Teflon rings so they conform and seal to their mated surfaces with more efficiency.
Confirming the Teflon rings are in their grooves and there is no twisting of the rings.
The next two pictures is to illustrate how the spool valve is attached to the stub shaft, the spool valve is tilted away from the mating peg on the stub shaft and lifted over the peg.
Then the spool valve is slid on to the peg, this is how it will be positioned when both the spool valve and stub shaft are assembled in the valve body.
Once the spool valve and stub shaft are mated with the valve body there's a pin on the valve body and a slot on the stub shaft that must be aligned together properly.
Apply some power steering fluid to the valve body and spool valve before gently pressing the spool valve in o-ring side first as shown, also make 100% certain the o-ring is sitting evenly on the chamfered surface inside the valve body before gently pressing the spool valve in, failure to do this will damage the o-ring and make it unusable!!!!.
With the spool valve partially inserted, note the position of the spool valve pin hole in relation to the slot on the valve body and the internal pin on the valve body, the hole and slot are at 90 degree angles to the internal pin on the left. also there's a little dimple above the pin hole on the spool valve to use as a quick visual alignment aid.
Install the stub shaft in the valve body/spool valve assembly making certain to hook the pin in on the spool valve and aligning the pin and slot previously mentioned on the sub shaft.
Add some power steering fluid to the back side of the stub shaft and place another o-ring in as shown.
Take the stub shaft bearing assembly and press in the new seal.
Confirm its seated all the way in.
Install the o-ring on the rack piston nut.
Then install the Teflon seal OVER the o-ring previously installed.
Inspect the Teflon ring is properly installed and not twisted.
Place the worm shaft inside the rack piston nut on the opposite end of the Teflon ring.
Place one half of the ball guide in as shown, the little tang on the ball guide will aid in assuring the rack balls don't go the wrong way when inserted.
This is to show the size difference in the different colored rack balls, the silver balls are .281 of an inch in diameter.
The dark silver rack balls are .280 of an inch in diameter.
Start inserting the rack balls in an ALTERNATING color order, dark light dark light etc; in the left hole on the rack piston nut. It don't matter which color you start with as long as the balls are put in the alternating dark light dark light order. I started with a silver ball.
And next is a dark silver ball, repeat this 18 times.
You will see the first ball you put in starting to appear in the right hole on the rack piston circuit once you have 18 of the balls inserted.
The reason the balls are put in the alternating color order is as stated previously the black balls are smaller than the silver balls. The balls must be installed alternately into the rack piston circuit and ball guide. This procedure maintains worm shaft preload.
Take careful note of what order the ball color is in the rack piston circuit, then remove the ball guide placed previously in and place the remaining 6 balls on their proper color order in the ball guide, use some petroleum jelly on the ends of the ball guide to prevent the rack balls from falling out when being installed and cover with the other half of the ball guide.
Carefully place the ball guide in the rack piston circuit.
Confirm the ball guide is seated all the way in the rack piston circuit holes.
Place the ball guide clamp on and insert the two ball guide clamp screws, torque them to 43 foot pounds... (Just a side note)..... i have done a bit more research because i was really doubting the 43 foot pound torque rating on those two tiny bolts and found some manuals say 4 to 3 foot pounds. I personally torqued it to 20 foot pounds and loosened them again making a mental note of the force it took initially to unfasten the bolts and a bit more was required, but none the less those bolts are not going anywhere with the 20 ft pounds of torque i applied to them.
I took my home made rack piston arbor and carefully mated it up to the worm shaft and proceeded to rotate the worm shaft COUNTERCLOCKWISE while maintaining arbor pressure on the end of the worm shaft till the worm shaft was disengaged from the rack piston nut.
Place the worm shaft on end and lube the thrust bearing surface with power steering fluid, then place the thrust bearing race on the worm shaft, (NOTE*) if your thrust bearing races still have a concave shape to them, place the concave shape so the inner diameter of the concave faces higher then the outer diameter of the race (like an upside down cone in relation to the worm shaft on its end in the picture shown below).
Place the thrust bearing on next and lube with power steering fluid.
Place the second thrust bearing race in the same orientation as the first race. Another side note, see the 2 machine grooves on the outer diameter of the worm shaft?, this is a marking intentionally placed on it to indicate its a 12.7:1 ratio worm shaft.
Mate the worm shaft to the valve body/stub shaft assembly. Note the position of the slot on the valve body and the pin on the worm shaft, along with the 2 tangs on the worm shaft that insert in the slots in the stub shaft, this is what rotationally locks the assembly together.
Lube the bore where the valve body assembly is to be inserted with power steering fluid as well as the Teflon rings on the valve body then carefully insert the worm shaft/valve body/stub shaft assembly in.
Be careful when the Teflon rings are about to be pushed in that they are evenly seated on the chamfered surface on the bore of the steering gear housing then firmly push in.
Install the sealing o-ring on the stub shaft seal/bearing assembly.
Confirm its seated properly and then lube the stub shaft seal, shaft bearing and thrust bearing with power steering fluid.
As a safety precaution i put a little box tape on the stub shaft splines to protect the stub shaft seal when installing the stub shaft seal/bearing assembly in, then install the assembly in thrust bearing side first.
The assembly is in and the tape can be removed from the stub shaft.
Screw in the adjuster plug by hand till you can no longer turn it. At this point i highly suggest placing the steering gear on end so the stub shaft is pointing up and use a rubber, plastic or leather mallet and give the stub shaft a light to moderate force tap or two to seat all the components in prior to screwing the adjuster plug all the way in.
Using the spanner wrench i screwed the adjuster plug in till it felt like it bottomed out using a light amount of torque force.
Made reference marks and measured them 1/2 inch apart from each other and back the adjuster plug off to the second mark to pre set the thrust bearing preload.
Then use an inch pound torque wrench to dial in the bearing preload between 4 and 10 inch pounds, I set mine to 5 inch pounds.
The rack piston nut can now be installed, lube the steering gear housing bore and the Teflon ring on the rack piston nut with power steering fluid.
With the teeth of the rack piston nut facing the side cover opening side of the steering gear housing, carefully insert the rack piston nut holding the
installer tool firmly against the end of the worm shaft and slowly turn the stub shaft CLOCKWISE and you will see the rack piston nut being drawn into the steering gear housing bore.
The rack piston nut is in and you can see the ball bearing are in place.
A simple test is to back the piston all the way in by continuing to rotate the stub shaft clockwise till it stops, then back it out 1 1/2 turns counterclockwise if the rack piston nut teeth are centered in the side cover opening then you had success!!!.
I also put some box tape on the sector/pitman shaft splines to protect the pressure and dust seals in the steering gear housing in preparation for its installation. At this point pour a little power steering fluid in on the sector/pitman shaft bearing and seals in the steering gear housing.
Lube the sector/pitman shaft with power steering fluid also and carefully insert it in the steering gear housing,
Once the sector/pitman shaft is in take the box tape off the splines.
Pour some power steering fluid on the worm shaft then screw on the rack piston nut plug.
Secure the steering gear housing and torque the rack piston nut plug to 111 foot pounds. Make certain if your sector/pitman shaft is in a position to fall out that its secured temporary while the plug is torqued.
It might be necessary to rotate the rack piston nut via the end plug a little to align it with the sector/pitman shaft, also recheck to make certain the teeth of the sector/pitman shaft are meshed properly with the rack piston nut, adjust if needed.
Install the side cover gasket on the side cover with the rubber inlay protruding into the side cover cavity.
Fold both tabs over the side cover to secure it.
Pour some power steering fluid on the meshed teeth of the sector/pitman shaft and the rack piston nut and the bushing in the side cover. Place the side cover on the sector/pitman shaft adjuster and back the adjuster in (COUNTERCLOCKWISE) till it stops and the cover is on the steering gear housing.
Screw the 4 side cover bolts in all the way making certain none are binding and torque to 44 foot pounds.
Screw the preload adjuster nut on till the top of the nut is flush with the top of the preload adjuster screw.
Turn the preload adjuster screw in one turn (CLOCKWISE) and start with the over Center adjustment. This adjustment is VERY critical to proper operation, on a used steering gear over 400 miles the adjustment should be 4 to 5 inch pounds MORE then the thrust bearing preload and never exceed a combined 18 inch pounds or excessive wear will occur and you will soon have a loose steering gear once again.
To achieve this measurement center the rotational travel of the steering gear (1 1/2 turns), (To confirm the center of rotational travel turn the stub shaft clockwise till it stops and then turn it counterclockwise 1 1/2 turns), Then place the torque wrench in the vertical position on the stub shaft. Rotate the wrench 45 degrees each side of the center and record the highest rotational torque on center. I set mine to a total of 10 inch pounds of maximum rotational torque. once set tighten the adjuster nut to 20 to 35 foot pounds (choose your preference) while securing the adjuster screw from moving.
Install the adjuster plug nut and hold the position of the adjuster plug with the spanner wrench while tightening the the adjuster plug nut.
(NOTE!!!***) Its been brought to my attention that some are having issues with placing the O-ring in first then the end plug, Although this method worked fine for me,You can also place the O-ring on the end plug FIRST before installing the end plug. MAKE CERTAIN to LUBE the O-ring and the end plug bore with power steering fluid BEFORE placing it in the steering gear housing!!!.
Press the housing end plug in till its bottomed out and you can clearly see the retaining ring seat. If you cant press it in with your thumbs use a rubber mallet or a plastic hammer and GENTLY tap the end plug in.
Press the retaining ring into the retaining ring seat making certain the end of the retaining ring is at least 1 inch away from the access hole.
This is to illustrate the positioning of the retaining ring position in relation to the access hole.
You now have an assembled Saginaw power steering gear ready for use!
Yes yes yes! Where did you pick up your rebuild kit?
Excellent writeup! :congrats:
This will be added to the FAQ shortly.
(edit) added to the FAQ! How To Rebuild Your Saginaw ZJ Steering Gear
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