The Stovebolt Site Forums The Shop Area Driveline Steering Box Lubricant

I didn't want to hijack Roads Scholar's thread but this is related to his.

I have no problems with my steering. It doesn't jump around, there's no slack it it so I'm probably just poking a hornet's nest here. Anyway, I decided to look inside and it's packed with thick reddish brown grease.

Jon G suggest a 50/50 mix of Corn Head grease and 90w mineral oil in order for it to reach all areas of the gear itself.

I'm not removing the gear or rebuilding it. There's really no way to get all the thick grease out without disassembly.

What I was wondering is if it would make sense to add 90w mineral oil to the box and hope that the action of steering operation would mix the grease and oil together inside.

Or, should I leave well enough alone and forget about it?

That's a very good question, Otto. I can see where adding the Mineral oil could loosen up the grease that's in there but I'm also thinking about it creating a leak at the seal on the shaft. I "overhauled" my gear box by installing new bushings and a new seal and then filled with cornhead grease. My initial issue was play in the output shaft ( a lot ! ). If you end up going with the oil added, let us know how it turned out if you would.

Otto - I did what you are describing and it promptly ran out my pitman seal. Bright side, found and eliminated one more leak.

Once I replaced the seal, I did the 00 cotton picker grease.

Steering works, no leaks. I should probably just leave whatever kind of grease is in there alone. No need to open another can of worms.

Sounds like a plan. Don't like worms.....unless they are on a hook.

As I believe I mentioned before I am only speaking for the AD trucks...and I will admit I only have only spent 62 years fiddling with them. You folks can use corn head grease if you wish. Undiluted it is not correct and not what was meant for the AD steering gear and there is explanation of that by GM. If GM wanted you to use a thick grease, they would have not put a pour-in plug at the top...that much should be easily understood. And they would not have written this in the Shop Manual:

"The steering gear is filled at the factory with a special all-season gear lubricant. Seasonal change of this lubricant is unnecessary and the housing should not be drained. Whenever required, additions should be made using a lubricant which, at low temperatures is fluid and will not "channel" or cause "hard steering" and which will provide satisfactory lubrication under extreme summer conditions."

GM goes on to explain the pipe plug is positioned so as to prevent over-lubricating and that you should never use a pressure gun to force lubricant in the unit.

It is a design issue...the engineers had reasons for wanting it this way. If anybody in the audience is pouring corn head grease out of a grease tube into that hole, please take a video of it. I would really enjoy seeing it happen. Below are a couple of images of corn head grease. It is packaged in a grease gun tube for a reason.

The thing with thick grease is, it gets pushed out of the way and doesn't return. You could very well have a box full of grease and still have the gear teeth going metal on metal, and it's even worse if the gear box has a line of roller ball that run on the worm shaft.

If you pull the side cover off the gear box and carefully dig out what you can, you can make room for room gear oil. You then can reinstall the cover without changing the adjustments. At most you might have to cut a new gasket. Add some gear oil and work the steering back and forth. Your reddish brown grease is likely contaminated with rust, giving it the reddish brown color. At the lowest point in the gear box is the lower worm shaft bearing, most were barrel shaped and hard to come by, this is where water sets. I had to throw away two worm shafts before I found a good one due to crappy rusty grease.

I agree with you , Jon. I'm just wondering what I should do in my particular case. The grease inside my steering gear has been in it for more than 25 years at least.

I'm experiencing no problems with the steering but I got curious and removed the fill cap yesterday and discovered that the contents are more grease-like than oil-like.

I'm not going to remove the gear box so whatever is in there is probably going to stay in there.

Jon, would you recommend adding 90w mineral oil to the box? Would that accomplish anything?

I'll see if I can get a close up picture of the grease in the hole.

.

While we're at it, what lubricant is used in the shift linkage just up the shaft from the steering gear?

I would be hesitant to think 90 weight would combine well (or thoroughly to be exact) with the thicker grease (whatever that grease may be). Joe might have thoughts about this and we should see what they are. In an ideal world I would remove the box, clean it well and inspect things while I did that and replace the pitman shaft seal and gaskets, use thread sealer on everything else and re-adjust it. In a moment I'll mention something else about that.

As for the grease being brown...If somebody used the old style of wheel bearing grease in there or even the old style of chassis grease, it was naturally brown, got darker and thicker with age and it may have been sort of reddish in color. I have a couple of cans of the wheel bearing grease left here by the way. One is 50+ years old. We're having trouble with images it seems but later I could post some images of that grease so you could see it. It very well might mimic grease mixed with rust...especially one of the cans. This is what is called long fiber grease and not at all good for a steering gear. Some of that stuff actually looks and feels like somebody mixed hair in with it.

I don't mean to come down too hard on using corn head grease. A lot of people here seem to have convinced themselves it is the answer. Herd mentality isn't always correct as we all have learned but it can be compelling.

I was thinking while having a cup of tea and I don't have any idea how many steering boxes I've seen. Over 20 easily. A few of them simply could not be used because somebody had used the wrong grease or too little lubricant in them and some had harbored water (very bad). And we can't un-scramble that egg. No way to know what somebody did long ago. The wear on the sector gear of one was literally the stuff of highway nightmares. I'm not sure how anyone drove it in anything resembling a straight line. No adjustment was left at all so the wheels would just pick their own path.

If you do take out the steering box and make a project out of re-doing it, please automatically replace the pitman bushing and check the shims on the adjustment side. Because the pitman shaft/sector gear is predominately limited to partial motion under stress, that bushing wears out in an egg-shape and that in my experience makes it harder to seal that area. You know, the lubricant runs toward the bottom/top as you'd expect it would and the more it wears the more the shaft bounces up/down and leaks. The balls don't always require replacement and the top and bottom worm bearings are often pretty much okay with adjustment but I'd look at them to be sure. I hate to say it but those bearings in worn condition might be better than the offshore made ones you find today. Once you remove the sector gear just turning the worm shaft a bit can reveal a lot.

The shift linkage? There was a Lubriplate grease I always used. Can't recall the name of it offhand but it stayed put and did a good job.

Thanks for your input on the gear box. I think I'm just going to have to leave it alone for now. The truck steers too well. I installed shocks, wheels and tires 5 years ago and never had it aligned. I can let go of the wheel on the highway and the truck tracks perfectly straight. Tire wear is perfectly even across the tread. It's actually quite amazing.

There's no unusual behavior with the steering over rough roads , either so I'm virtually certain there is nop water or rust in the steering box. Eventually I may remove the gear and do all that you say but right now I don't need to do elective surgery on any of these wrecks. I have enough to do on them with actual problems.