Hi all,

I need to top up the steering box lubricant on my '75 Corvette—or more accurately, add some, as I suspect it’s been untouched for 50 years and is probably empty by now. I’m not ready to rebuild it just yet, so for now, I just want to add some appropriate grease.

Unfortunately, I’m not very familiar with the various types of grease, and almost none of the recommended products on the forum is available here in Europe.

From the factory, the box supposedly used 90W gear oil, but that seems too thin and likely to leak. Some suggest using grease in the NLGI 0–2 range.

I’m a bit concerned that NLGI 0 might become too runny when hot. And the selection on the market is limited too.

At the moment, I have a cartridge of Shell Gadus S2 V220AC 2 (NLGI 2) in my grease gun.
TDS: Shell Gadus S2 V220AC 2 PDF

Do you think this is suitable, or would something less thick be better?

Looking at the grease used in this article:
Rebuild Your C2/C3 Corvette Steering Box – Chevy Hardcore
…it seems to have a similar consistency:
https://www.speednik.com/wp-content/...-13_214130.jpg

Also, the Gadus’ 180°C (356°F) drop point seems adequate for this application.

I also found that BG 607 SLC is sometimes used and available over here too. But based on the TDS:
607 SLC Grease

I don't see a major advantage over the Gadus. What do you think?

Thanks in advance for any advice!

 

Bottom line. Putting new grease over the top will never get down into the ***** and tracks. Basically your proposing to "**** up a rope".
Just pull it out and put a kit through it. You'll never get the grease where you need it any other way.
And your looking for a high quality High Pressure grease that doesn't tend to liquify.

 

Thanks for the reply! I’ll be pulling out the steering column along with the other surrounding parts, but that’s planned for autumn / winter. For now, I’m just enjoying driving my C3 this spring and summer after a year of hard work—unless something serious comes up, that is

Anyway, in the meantime, I’d at least like to try putting something through the lid of the steering box, since I suspect there’s nothing inside. I doubt it’s ever been serviced. I’ll also check it with a borescope camera to be sure.

But thinking about your point regarding getting the grease to spread properly, NLGI 0 viscosity might actually be the better choice after all.

 

I went through the box in my 77 about 2 years ago. All that old grease was still in there. And plenty thick. Putting grease on the top will do absolutely nothing. No matter what type you use.
You must dissassemble and clean out all that old thick grease before any new grease can touch anything important in there. I'm totally serious. Your proposing to just **** up a rope. Your wasting your time trying to put grease on top.

 

From what I’ve researched, steering boxes were often — or almost — empty. But yeah, if the old grease is still in there, I’ll just leave it and deal with it after summer

 

Probably not worth messing with now, since you will be removing/refurbing this coming fall/winter. If your steering is really sloppy to the point of feeling 'at risk' when you drive it, verify ragjoint is in acceptable condition and evaluate need for adjustment to the steering box. We can advise on how to proceed if either condition is negative, in your judgment.

 

Thanks for the reply! The steering does have some play, but nothing unusual—at least compared to other C3s I’ve driven. I wouldn’t say it’s “at risk.” The reason I wanted to at least put something into the steering box is because the car had been sitting in the garage for nearly 20 years, and now I’m driving it almost daily. So I figured it might be a good idea to lube the steering box—at least a bit—to help prevent internal wear before I get to the proper refurbishment.

The rag joint is definitely shot; I’m pretty sure it’s still the factory original. I’ve scheduled it for replacement. I already tried loosening the bolts and removing it, but it wouldn’t budge, so I’ve postponed the job until autumn.

 

I rebuilt my steering gearbox and it's not that difficult. I used John Deere Corn Head Grease. The only issue is you need a dial type torque wrench to set the bearing preload and the high center gear preload. The kit I bought was great except for it had four 0.001" thick shims instead of the correct shim washers so I had to make a new shim washer. The service manual covers the rebuild process in detail.

My rebuild thread is here https://www.corvetteforum.com/forums...-overhaul.html

JT

 

That Rag joint looks like it is Totally shot from the pictures. I see that you put things off until the cooler weather because they might turn into a "project". When some people look at that joint and say "later" I see them as a "challenge". Mine was in terrible shape when I bought my C3 and it still came off and was replaced in less than an hour and I had never touched one before that time.

For hardware like that with rust all over it I would suggest the following procedure.
1. Using a Wire Brush the hardware to remove any loose material. I would also try and clean the shafts and other parts that will have to be disconnected from the steering box.
2. Heat up the hardware with a HOT AIR GUN and then drench/soak it with lots of Penetrating Oil like KROIL or an equivalent. Heating up the entire bolt will make the oil getting into the tight spots a bit faster.
3. Repeat above process with penetrating oil to ensure the oil has entered the joint and started loosening the joint up.
4. Using a 6 point socket try and get a socket securely on the nut. If you have the tube wrenches that wrap 2/3rds around the nut this would be a great place to use them.
5. IF the nut is still frozen on the bolt then you might need more heat. Once the joint gets hot enough the oil will be drawn into the connection and this will break it loose for you.
6. They do make a FREEZE SPRAY that you can also apply to frozen hardware to help break the parts loose. I have not used it but I hear it works.
7. The worst thing might be using a pair of Vice-grips to hold parts while you loosen them up. My Rag joint came with new hardware so I replaced everything in the kit.
8. Apply Anti-Seize to the hardware while re-assembling the parts to ensure the job will be easier the second time around.

Don't fear the rag joint, it is not that big a job to replace them. Just start the oiling process and get the parts loosened up. A Loose rag joint might make the steering pretty loose so I would probably do it before the summer months. This will let you enjoy your Corvette even more during the summer with tight steering again.

 

https://penriteoil.com.au/products/semi-fluid-steering-box-grease

Also have seen this grease recommended.

 

I just rebuilt a box that had the John Deere corn grease in it. It was the first time I checked it, since I don't use it in my builds. While it does cling to the metal, it is too thin for my liking. I would be concerned it will weep past the seals over time. While all grease has a drop point, the Lucas Poly has been the best grease I found to date. It is not as common to find as it once was because of a very long backorder, well over a year.

Adding grease to a box that has nothing left or a mix of sludge in it, won't hurt but it's not going to bring it back either. The box in the picture shows deep mesh already and if loose chances are the gears are shot. Some box casting, relatively few, are what I call deep boxes. Most were C2 boxes, although I had a late C3 box like that last year. These are castings that should have been rejected at inspection but were passed and used as is. While I doubt this box is one of those, you never know until you check it.

These boxes should not have any play on high lash, none. Note, high lash and true center are not the same and setting up a box at the wrong position will not provide the best steering. The common rebuild kits sold today have good bearings and cover gasket. I don't use them as I have my own stock and used to machine my own bushings. Now I have the bushings made to my spec and size them to each polished sector. The kits no longer come with a cover bushing.

 

Gary, I wouldn’t even think of trying to rebuild the steering box on my C3, it’s way above my mechanical skills. However I want to personally thank you for giving advice to other Forum Members. With at my advanced age, and lack of specialized tool, I am aware of my limitations. Thank you, from all of us.
Eli

 

If the Lucas grease is not available then corn head grease would seem to be the way to go if a mechanical type guy didn't want to wait a year for a tube of Lucas grease.

Not only do the kits not include the cover bearing the one I got didn't have the proper shim washer set instead they had 4 pieces of 0.001" shims while the photo of the kit showed the proper shim set. I chose not to use them and made my own bushing to get the gap down below 0.002". There was no wear on the cover bearing so I didn't try and replace it.

JT

 

My concern with the corn grease is the possibility of it weeping out under pressure. Mobil 1 is a good grease but not for boxes for that very reason.
The kits sold today are not like that once were when Tom Reina was in business supplying them, but it is what it is. I don't use them. You have the machinery to make some of the parts so that is positive but most don't have that option. I replace the cover bushings and fit them as well.

 

And I'm happy to lend anyone the adapters I made to press things for the gearbox. They just have to pay shipping.





JT

 

Thanks everyone for the replies!

@jthornton – Thanks for the link on the steering box rebuild, much appreciated – it’ll definitely come in handy! That John Deere grease might actually be available here in CZ. I couldn’t find anything online, but I’ll try calling some local JD parts distributors to see if they can order it.

@ctmccloskey – Thanks for the detailed instructions on removing the rag joint. I’ll give it another shot – why not? It doesn’t hurt to apply some bolt release daily and see if it loosens up, without risking damage in the process. I already have a new rag joint on the shelf, so that’s not an issue.
What is a problem—or rather, a risk—is that if I break something during removal, I’m stuck. Parts availability, including imperial fasteners, is a huge pain over here. It’s not like with a European car, where you can place an order and get the parts the next day (or even the same day) if they’re stocked in CZ. I’ve had situations where I couldn’t move forward with a project because I was missing some small part, and had to wait until I had enough items to justify placing an order from the US

@PJO – Thanks for the link, I’ll check it out as well—hopefully something locally available turns up.

@GTR1999 – Thanks for the extra details on the rebuild process. By the way, what specific grease is the “Lucas Poly” you mentioned? I looked through their product list:
https://www.lucasoil.com/products/grease/
...but didn’t find anything clearly matching that name. It’s probably not available here, but if I could find the TDS, I’d at least get an idea of the basic properties.

 

Your ragjoint is OLD, dirty, corroded, etc. BUT it is not yet "toast". The flex disc is warped, but it is not split. And that GM design prevents any loss of steering, even if the disc completely fails.
I'm stating this so that you don't get into a 'deep dive' into that steering area until you do your steering head removal. It makes no sense to do all that work for replacing the ragjoint, and then do it all again for updating the steering gear.

 

X-TRA Heavy Duty Grease – Lucas Oil Products, Inc. – Keep That Engine Alive!

 

Thanks for the evaluation and info! I believe the rag joint contributes significantly to the somewhat sloppy steering. As for eventually replacing it — I'm not opposed to doing it and enjoying improved steering a bit sooner, as mentioned above. However, judging by its current state, it doesn’t look like an easy job — especially removing it from the steering column...

Thanks also for the link to the specific product! I see it's available on RockAuto, which is great — I occasionally order parts from there, so I can easily add a cartridge to one of my future orders.

 

Since you have to remove the steering box later this year, just wait until then. With the box removed, the ragjoint is a piece of cake.