VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc …40 steering box lubrication

Without removing the steering gear box, is there a way to remove or flush out old grease from the inside? I know the old grease (80 years) is not doing it’s job. I just had the car up on a floor jack and moved the wheels left to right. I could feel and hear the gears more than I should.

Any good ideas?

Thanks,
Curt

There is no real way to flush but you could fill with say #90 gear oil and leave it in there or a few weeks when most of it leaks out and then fill with corn head oil/grease.

I expect that you get lots of different guidance on your question.

You need a lubricant that will flow enough to stay around the moving parts plus flow to lubricate the bushings. It also has to stick the the gear faces and provide wear protection. Yet it has to be thick enough that it will not leak out past the pitman arm seal.

My experience is that the often recommended John Deere Cornhead grease is too thick. It is a NLGI grade 0 grease which is considered very soft. It does channel and create pockets around the moving parts. None of it flows to the bushings. I am sure that in an operating gear box it gets warm enough that it will flow and still cling to parts. Those are not the operating conditions for a steering gear.

I am just finishing a rebuild of the steering gear in my '37. I plan to use the Penrite Steering Gear Oil which is a NLGI grade 00 grease. That is considered semi-fluid. As another reference NLGI Grade 0 is sometimes compared to the consistency of brown mustard and 00 to applesauce (I assume not the chunk style).

Some of the people on this forum have made their own mixture of gear oil and grease. They might be closer to what Chevy intended than you would think.

Thanks for that information Chev-nut and Rusty.
Curt

I should clarify. The mixture needs to be made first and then put into the gear box. There is not enough agitation in the steering gear box to properly mix and achieve a consistent and uniform mixture.

The more than I think about it if I were you I sure would give a home brew a try. Anything you do will be better than running with the box dry.

I have read about some people using high viscosity outboard motor lower unit grease. Might be an interesting and quick way to see what happens. The really tricky part is to find something that flows around the gears but does not leak out.

Additionally there are a few people who promote using STP. While it might have the desirable viscosity and flow characteristics, STP is not a lubricant. It is an additive that increases viscosity and adds chemicals to other oils.

I am using STP mixed with chassis grease. Have had it in my rebuilt box for close to twenty years.

Note his original question was fflushing and not th gear oil.
For gear oil I have always used a combination of chassis grease and gear oil, First I fill with straight #90 and when that leaks out top off with chassis grease. The gear oil will seep into the bearings and othertight places.The two will mix whiles driving and turning.
STP is not a lubricant but rather an polymer oilt thickener.

I’m going to add some 90 wt gear oil tomorrow. Hopefully it will work it’s way down to the gears and perhaps reactivate or mix with some of the existing grease. As mentioned in previous posts, I’m sure there are pockets of no grease in the gear box. The 90 wt should hopefully fill in those areas.

Since there is only an oil fill hole on top and no grease fitting, was the lubricant used back in 1940 a heavy gear oil like 90 wt? Or did they somehow pack it with chassis grease during assembly? If grease was used, how do you add new grease without a grease fitting?

The factory lubricany was a thick gear oil and was poured in slowly. If you do add chassis grease just remove the fill plug and insert the tip of the grease gun in and give several pumps. As it settles later retop it with a little gear oil and more grease.

Thanks for that info.
Curt

I added gear oil to the steering box today. The steering is much better than it was.
Also, I adjusted the backlash. What a world of difference that makes! No more slop in the steering wheel nor the left to right wandering on the road when going over rough areas.

I’ve been putting off adjusting the backlash in the steering box for a very long time. I found it not at all difficult. If you do exactly what the manual says, it’s hard to screw up. (It only takes very small adjustments!) Since it was my first time and I had to figure out what size tools to get (9/16, 7/8 wrench, sockets, etc.) it took about 45-60 min. It’s much easier to have a helper.

Curt