The Stovebolt Site Forums The Parking Lot Big Bolts C60 Saginaw Manual Steering Box preload specs

So I got the kingpins and brakes and new drum sorted on the captain's side, and while I've got the pitman arm free for new drag link installation, I figured now would be the time to adjust my Saginaw steering gear box to the proper preload. The steering works great and the box goes lock to lock without any noise or grinding, it seems sound. I could get motivated and find/install a new sector shaft seal, I suppose.

I rebuilt the smaller version of this box in my old Pontiac Tempest, so I've been inside one before. The Pontiac service manual gave preload specs in in-lbs, which is great because I have several such torque wrenches around, they being useful in the bicycle world of carbon fiber and critical torque specs. However, the GMC truck service manual I have, gives the preload in lbs of pull on a spring gauge on the edge of the steering wheel. 1-1/2 to 2lbs of pull is the spec. For Pitman shaft, it just says loosen lock nut and turn adjuster til all the slack is gone, then snug the lock nut back up. Test pull again and it should be in the vicinity of 3lbs pull on the spring gauge.

How would spring gauge pull be expressed in in-lbs? I ask because where in the world would I be able to find a spring pull gauge in this day and age.

Also, the 'SG' lubricant that GMC recommends is described as a special steering gear lubricant No. 0 grade with low cold test characteristics and extreme pressure properties. I fear that it is no longer marketed by various oil companies, as the manual suggests.. however it states that GM code 'MP' lubricant may be used for replenishment and the description of that reads a lot like 90w. May I just use 90w like my Dad did, or is there something better?

BTW, when I overhauled the gearbox in my Tempest, it was suggested to use CV axle grease, with which I filled the housing up to the required level. That goop seemed to work perfectly as it essentially turns into semifluid in use.

Ignore the spring gauge adjustment specs- - - -they're sort of a "Measure with a micrometer- - -mark with chalk- - - -cut with an axe" process. Virtually any steering gear, regardless of make works well with a 10 inch pound rise across the center point. Find the center, turn away about 1/2 turn in either direction, and use a deflecting beam torque wrench on the center nut of the steering shaft. Turn the gear across center, and adjust the sector preload screw until the torque rises 10 inch pounds as you cross over center. Your turning torque should drop back to the original reading once you pass the center point. If you get a rise/fall/rise reading as you cross over center, the gears are worn out and can't be adjusted correctly. This procedure has worked for me on all makes of worm and sector steering gears for over 50 years. Steering gear only- - - -no linkage connected at all to do it right.
Jerry

Thanks! That sounds like about the difference in preload from when I did my car steering gear. I remember the sector shaft preload being about 13 inch/oz for used bearings, but I sure with I had the actual spec for this larger gearbox. When I got the rig, one of the first things I did was tighten the steering box, the input shaft had up and down play til I tightened it enough to remove that. I think it was sloppy enough to never sit in one spot long enough to brinnel a bearing :-D

The other thing I'd like to find is the sector shaft seal, the shaft is 7/8" in diameter and the old one is leaking. Pitman shaft is dry, so I'll go ahead and leave r be. But I'd like to seal up that input, then complete my Craigslist overhaul with a coat of safety black Rust-O-Leum enamel.

It'd be nice to find a part number, but I guess I can also just measure ID, OD, and thickness and match it up that way.

Tronman, This SEAL might be what you are looking for. The last pic attached to the ad is snagged and displayed below to show the vehicle application info which seems to match your 1965 C60 info.

Yes/No/Maybe So???

@Gdad51 that sure looks like the one!

[edit] This seal crosses to SKF part number 8637, and local parts house was able to order one in for me, $12 total for part and shipping. Forty bucks seemed pretty dear for a little seal..However I did measure the shaft and the bore, and it seems the correct one.

A little bit of extra drag across center won't be a problem. The only purpose of an increased effort over center is to prevent steering wander while driving straight down the road. Of course, there needs to be a way to be sure the straight ahead position of the wheels coincides with the center point of the steering gear. I have also fabricated an adjustable drag link by using a couple of tie rod ends and a turnbuckle type adjusting sleeve.
Jerry

Tronman, Glad the info helped get you what you need! 👍

Good job on finding a better price. 😉