Power steering gearbox rebuild question

[greywurm]

It's a Saginaw power gearbox on my 71.

I completely blanked when disassembling the gearbox and did not mark the position of the shaft and lock nut. When I get to reassembling, is there a procedure to follow to make sure it gets in the right position?

Also, the access plug on the square gear with the bearings doesn't have a socket head to it. It just has a square shallow hole that my 1/2" breaker bar fits into. Problem is that it's too shallow and I've started boring it out to where the bar just slides out. I think I'm just going to leave it as I've gotten all the bearings out and sprayed a bunch of degreaser in there to clean it out. Think I'll be ok?

Sorry for lack of correct terminology... This is my first teardown of a gearbox.

[randy500]

The sector shaft only goes in one way with the center tooth in the center of the square gear/piston.


the pitman arm has locating splines and can go on I think every 90 degrees or only in one spot.
I don't recal the square plug but if you got worm gear out all the balls will shake out so no need to remove the plug.

[Bigdav160]

The square gear, I think, is called the ball nut. The threaded access plug allows retrieval of a dowel that holds the bearings in place while the worm gear is threaded in.

You can get the worm gear threaded without the dowel but, with the threaded plug in the way, you won't know if the balls stayed in the groove.

Make sure you get all the pins aligned properly in the spool valve/worm gear. It's most important to get the proper torque on the adjuster plug. Directions are in the service manual.

[greywurm]

I've attached a pic of the access plug. It seemed odd to me that it isn't a nut head like I see all over the internet. I also have a 22 ball box - it seems that varies as well.

I didn't put any marks on the input shaft cap and lock nut. I think I could just torque that cap then back it off a little, like an 1/8 turn before throwing the lock nut on there.

I did not touch the adjuster nut that is on the cover with the pitman shaft, assuming that it is ok where it was at.

I've seen an assembly done without a dowel where you put the bearings in one at a time and keep threading the worm gear. Looks like it isn't the easiest, but can be done.

I am doing the rebuild because it leaked like crazy and there is a ton of play. Driving on the highway can be a workout keeping the truck straight, so I haven't driven it much in the last year, probably since my son was born last February, due to it not feeling safe. Just trips to the soil yard or Home Depot which is about a mile each way.

[greywurm]

What I'm calling the input shaft cap I guess is called the adjuster plug in my rebuild kit instructions. It requires a spanner wrench or some luck+needle nose plyers. That's the part I did not mark the position before I loosened it up.

[randy500]

Originally Posted by greywurm

What I'm calling the input shaft cap I guess is called the adjuster plug in my rebuild kit instructions. It requires a spanner wrench or some luck+needle nose plyers. That's the part I did not mark the position before I loosened it up.

The adjuster plug you refer to is critical for wheel return and "play" in the box. You can easily make a spanned wrench with flat stock, drill holes and insert small bolt in the hole with threads cut off.
Buy a inch pound bean torque wrench to set preload.
Even more critical is the over center adjustment of the sector shaft bolt and you need the same torque wrench for that too.
You will also need to adjust the clearance of that bolt where it slides in the sector shaft slot.
I set everything to to the tighter end of the specs so when it wears it wears into spec.

[randy500]

Every tolerance spec is critical to eliminate play and for proper steering wheel return to center. If not set properly you could have erratic dangerous power assist and the box will not return to center which is very dangerous.

[randy500]

You could grind a tool such as an old 1/2 in extension cut down to tightly fit that rounded off end nut and heat it up a bit to get it out

[greywurm]

Thanks guys, Randy especially.

So I just need to torque the adjustment cap nut to spec with a spanner nut, and the adjustment screw on the sector shaft? I have an inch pound torque wrench... Cheap one but it's worked for me in the past. The downside is if I remember correctly, it's basically guess work on what the setting is between increments of 120 in lb.

Do these specs below I found look right? They are all in ft lb.

Also, where can I get a good replacement piston plug if I were to get the rounded out one off?

Power Steering Gear
Adjustment Cap Locknut. . . . . . . 108 N-m (80 ft. lbs .)
Adjustment Screw Locknut . . . . . 49 N-m (36 ft. lbs .)
Gear to Frame Bolts . . . . . . . . . . 95 N-m (70 ft. lbs .)
Pitman Shaft Nut . . . . . . . . . . . . . 251 N-m (185 ft. lbs.)
Rack Piston Plug . . . . . . . . . . . . . 102 N-m (75 ft. lbs .)
Side Cover Bolts . . . . . . . . . . . . . 60 N-m (44 ft. lbs .)
Pressure Line . . . . . . . . . . . . . . . . 28 N-m (21 ft. lbs .)
Return Line . . . . . . . . . . . . . . . . . 28 N-m (21 ft. lbs .)

[Bigdav160]

The adjuster plug gets torqued to 22 pound feet and then backed off 7/16". Install the lock nut. If you assembled the spool valve correctly there will only be a couple threads of adjuster plug showing past the lock nut. Jam a no-name cheap 12 point socket over the input shaft. You're going to need to measure the rotational force of the input shaft while tightening the sector. With the box centered measure the rotational torque to turn the input shaft. Turn the sector adjustment screw to obtain 10 pound inches more turning force. Tighten the sector lock nut.

[randy500]

You should carefully read the rebuild manual. The inch pound spec is a steady rotational force applied to the where the rag joint attaches(hammer a soft socket into it, think Taiwan made) The base adjustment if I recal is for the spool valve bearings. Then you adjust the sector shaft bolt and lock nut for inch pounds rotational force in addition to the base rotational force on the spool valve bearings. It's all explained in the rebuild manual.
On a power box you can also adjust the clearance on the sector shaft adjustment bolt where it slides in the slot of the sector shaft. I don't recal the spec but it's measured with a feeler gauge under the rounded portion of that bolt. The tip of the bolt wears and needs to be adjusted. If you don't adjust this clearance it will allow the sector shaft at time to be pulled onto the worm nut and bind, the lock nut only adjusts the outer limit of gear mesh(upwards) the adjuster inside the box limits downward travel of the sector shaft, both adjustments are equally important

[randy500]

I will add a bit more info...
The outer bolt and nut like I said adjusts the gear mesh, think of it as backlash in a ring and pinion gear but in this instance the clearance is measured in inch pounds of rotational force. The adjustment of the mesh can only be done off the car because of this rotational force measurement. Also it can never again be adjusted after put in use and any wear has taken place in the box. Never adjust this on a used manual or power box because there is almost always wear such that the sector shaft slot has excessive clearance...if you do adjust it, the adjustment would be inward yet the excess clearance in the slot with the new adjustment(inward) now will allow the sector shaft to mesh too far with the square gear and binding will result which prevent the steering wheel from returning to center on its own without steering wheel input.
The steering returns to center because of variable clearance in gear mesh of the sector shaft to the square gear(ground into he gears) there is tighter gear clearance off center than directly on center, this causes the gears to find their way to the least resistance which is straight ahead. It's also why it's important to install the steering box with the sector shaft centered and adjust the tie rod sleeves to center the wheels to the steering gear box.

[greywurm]

Ok. Thanks for all the info. I have to think on this a bit.

[randy500]

I will give you one more tip, the sealing rings on the spool valve and the big square nut (I need to look up the name of this) are made of teflon and they get stretched when you work them onto the parts, be careful you don't nick them, they probably make shields to protect them as they are fitted, I don't think you would be able to find the shields though.

After you install the Teflon seals they are stretched and need to be compressed before the part is installed, otherwise they will cock in the bore and get damaged.

You can compress them with a hose clamp. Protect the seal with a piece of oil jug or plastic milk carton to wrap around the seal, them clamp slowly with a hose clamp and let sit overnight or so for them to shrink before installing the parts.

[greywurm]

My kit calls the square gear with the bearings a rack piston.

Good point on the Teflon seals. Everywhere I've read stated they are a bear to get on and to take it slow. One guy suggested letting it sit overnight to shrink down but I like the hose clamp idea.

Do you think I need to get into adjusting the screw for the sector shaft if I haven't touched it? I was thinking that if I don't touch I wouldn't need to mess with it... But maybe because I'm starting from scratch with the adjuster plug I have to do both?

I don't have a service manual. I have a Haynes and Chilton's for the truck but it doesn't cover the gear box, just removal and installation. I'm going off of forums, YouTube videos and different articles I've dug up. Everyone says to mark the plug before removal and I totally just jumped into taking it apart even though I knew better.

[randy500]

Originally Posted by greywurm

My kit calls the square gear with the bearings a rack piston.

Good point on the Teflon seals. Everywhere I've read stated they are a bear to get on and to take it slow. One guy suggested letting it sit overnight to shrink down but I like the hose clamp idea.

Do you think I need to get into adjusting the screw for the sector shaft if I haven't touched it? I was thinking that if I don't touch I wouldn't need to mess with it... But maybe because I'm starting from scratch with the adjuster plug I have to do both?

I don't have a service manual. I have a Haynes and Chilton's for the truck but it doesn't cover the gear box, just removal and installation. I'm going off of forums, YouTube videos and different articles I've dug up. Everyone says to mark the plug before removal and I totally just jumped into taking it apart even though I knew better.

Its critical to check the end play in that adjusting screw which slide in the slot of the "rack piston" (thank you). It should have virtually zero play, the adjusting nut is built in or something like that and might be "staked" don't overlook it.

I will check my manuals to see if I have instructions....otherwise go to the library they should have the manuals, mine used to have them but I haven't been in there in about 20 years.

[randy500]

Text me at 253 414 4637 with a short note. Steering gear and I will take a picture of the factory service manual instructions. If that isn't reaadable I will scan the book pages, my scanner is slow so lets try a picture first.

[randy500]

Actually send me your email and I will scan this. There is a exploded view which you may need

[randy500]

I scanned the manual if anyone needs it...its 2 PDF files, page 6 is not clear in the original scan so I scanned it separately, I only have PDF viewer so am not able to combine the documents.

Its a Pontiac manual but as far as the steering box goes the manual is for a Saginaw 800 or 808...

[greywurm]

Originally Posted by randy500

I scanned the manual if anyone needs it...its 2 PDF files, page 6 is not clear in the original scan so I scanned it separately, I only have PDF viewer so am not able to combine the documents.

Its a Pontiac manual but as far as the steering box goes the manual is for a Saginaw 800 or 808...

I'll text you my email in the morning so its not too late at night for you. I can put them together and post here for everyone that may be interested. Thanks a bunch for doing the scans. You've been a great resource thus far.

[greywurm]

The PDF is too large to upload to the forum for me, so I am linking to it directly in my google drive. Great scans Randy!

Power Steering Gear Procedures

[greywurm]

Google has changed their security settings so the old link isnt available anymore. The file is available here:

Power Steering Gear Procedures

Please ignore the old link in post #21

[slikside]

Sub’d. Great info. Thanks for updating the file!