Power steering box rebuild

[randyscycle]

Today was steering box rebuild day. I installed the power steering on my M715 back last winter as I built it, and should have done the box then, but it was relatively dry albeit a bit covered in road grunge, so I washed it off and used it as is until a week ago when it sprouted a leak at both the input and pitman arm shafts.

A little history on the box: It was procured from e-bay for $30 on a buy it now and $25 to ship it Fed Ex back in November last year. It was from a 1980 Grand Wagoneer. It is the “76” casting. It is a Saginaw 800 series box. It bolted on with zero mods, but does have the metric fittings. I used the pitman arm that was on it and it bolted on with no reaming or modifying. My steering geometry is as stock and does not steer too quickly or erratically. I still need to sleeve the frame for the fourth bolt, but after a couple thousand miles and some wheeling, I have had no issues and it was as tight as when I installed it, when I removed it this morning. Here are some pics of the rebuild. Keep in mind a few things:

• Clean is the key word here. There are some very critical valves and seals that rely on almost perfect fit to seal and will only go together if there is NO dirt or debris.
• Check all the bearings both thrust and needle roller. They are generally OK as they are immersed in fluid constantly, but if they do wear, they tend to also wear a strange pattern into the rack and sector gears and usually make the box unserviceable.
• Flush the pump before reinstalling the box. I did this by blocking the return hose pouring new ATF in the pump while running and hanging the pressure hose in an empty container until it ran clean.
• Watch how the box comes apart and goes back together. The recirculating ball type boxes are a bit tricky to reassemble, but not impossible. The rebuild kit comes with instructions and they are a bit generic, but can get you through the job.
• Use only clean ATF for reassembly lube.
• When you reinstall the box and first start the truck DO NOT stick your hands in the wheel! If there were an issue with the valve, or something was incorrectly installed the wheel could snap sharply to one side removing your arm, hands, digits, etc. Not a good ending to the day.

Here is a good example of the leak points on the Saginaw boxes:



Here is an example of the clean thing I mentioned. These things are full of abrasive filth and goo. This is also a good argument for flushing the power steering on a regular basis:



Here is the “76” casting on the box on the bottom near the front. You can also see the reinforcement web cast over to the pitman arm seal housing:


This is how clean things need to be:


More in the next post……….

[randyscycle]

A layout of all the parts ready for reassembly with all the new Teflon seals installed:


This picture is here to make a point and show a common wear point on Saginaw 800 steering boxes. This is the area where the spool valve rotates in the case each time you turn the wheel. The Teflon seals wear the case somewhat in all higher mileage boxes. This one was pretty darn good, and I have seen worse in service and still work acceptably. I usually rebuild rather than replace with a reman and here is why: The reman boxes I have had apart always sleeve this area with a bronze sleeve. While I don’t have a problem with that, I do have a problem with the fact that when this is done, the sleeve is nearly 1/8” thick, and that means boring that much out of the housing, considerably weakening it. Probably OK for a passenger car, but in a heavy duty wheeling application, I don’t like it.:



Here is the kit I used from NAPA P/N: 7-181:


Here is the assembled finished and adjusted box ready to go back on:


I’m happy to report that it works excellent with no leaks and the steering is much smoother and more effortless now with all new seals and fluid. Truly “power” steering. I will also be adding a cooler very shortly.

[rpgdeity]

Wow! Excellent post, I'm looking to do this very soon, like next week probably. What is the part # for that rebuild kit? Is it the R802967?

[randyscycle]

7-181 is the NAPA part number.......fits the 605 and 800 series Saginaw boxes and comes with the proper seals for both.

[gimpyrobb]

SA-WEET! Great post Randy, thanks for your time in recording this for the group.

[LuckyPabst]

One thing to mention - the little balls are sized differently. Half should have a black finish and half are shiny. One set is .005" smaller than the others and the balls need to be alternated when you reassemble the box.

Chris

[porkchop]

Chris, you beat me to it. I found that out the hard way.

I messed with my power steering this weekend as well. I didn't have to rebuild the box but I had a leak from the pressure hose at the box connection. Has to take it off cut and reflare the end to get it to stop leaking.

[Roy]

Good work...nice post dude.

[randyscycle]

Thanks for mentioning that Chris.....I totally forgot to add that detail.

[Kaiserjeeps]

What a fantastic post Randy! Great pictures. Rebuild numbers and everything. I'm going to have to give it a try. I have never tried to rebuild a box. Thanks for mentioning the sleeve thing.
I have a question for you or anyone who might have an answer.
This is for the CJ. I have had PS with the 76 box on the rig for numerous years. When I am off idle or 1K RPM or so I don't seem to have much assist sometimes. Offroad on a big rock slow trails my power steering over heats and looses assist if pushed hard enough or long enough. The pump is a pretty new (~5 yrs) re manufactured pump compared to the junk yard box with came from a firebird direct swap. . I have a small PS cooler and a filter with a magnet in it I have not installed yet.
The adjustment on the top with the 5/8ths jam nut and allen set screw is about half way down. I am also getting death wobble again.
Could a bad box overheat my system when pushed a little?

I run a tight LSD, not a locker like some of the guys. They have no problems all day. I have not been able to solve this. I did not want to buy new cause I'm cheap.

Don't want to hijack which I accidentally do sometimes. Seems like a good time to ask.
Thanks for the post.