Featured Technical TECH: Steering Box Rebuilding for Early Fords/F1/F100

Is it Tech Week? The old timers will know what I'm talking about.

I decided to throw together a tech post like in the days of olde and hope this will be of use for some of you out there.

I just got done with a 37-39 Ford steering box rebuild and tried to do***ent most of the steps.

As you may or may not know, Gemmer made steering boxes for Ford, Chrysler, Hudson, Nash and others. Their Gemmer III rolling sector design hit production in the 1937 year model. This was a huge improvement over the previous Gemmer I fixed tooth sector design used in 32-36 Fords.

The discussion here will relate to the Gemmer III rolling sector design, so will be applicable for many late 30's through early 60's Ford, Mopar, Nash and Hudson boxes including 37-48 Ford cross steer boxes as well as 48-52 F1 and 53-60 F100 side steer boxes.

I've rebuilt better than 500 of these boxes over the last 15-20 years, but continue to learn more and more about the design and adjustment to hopefully improve upon my processes. Ultimately the goal is to build a better steering box, addressing as many of the shortcomings from the original designs as possible. That all said, I'm no expert here, just trying to share some things I've learned along the way.

Starting here with your typical rusty, crusty, greasy steering box core



The first step of course is to fully dis***emble the box, clean and evaluate parts



One of the first tasks is to rebuild the sector shaft. After a clean and polish, the roller typically needs to be replaced. Even if it is not galled or pitted, if it shows more than 0.002" side play, I will replace it.

I made up these aluminum blocks to hold the sector shaft in the mill vise, so the roller pin is in a vertical position. It can just as easily be clamped up in the vise and checked for position by eye.



I use a 1/2" carbide end mill to knock one end of the roller pin off. This can also be done with a carbide burr in a die grinder. Just go at it carefully until the head is removed and then the pin will knock out in the press or with a hammer and drift.



Next step is fitting the replacement pin and roller kit. The new thrust washers they supply are too thick to use as is. You might get lucky and be able to use the originals that came out with the old roller. I measure the sector, then the roller, subtract and divide by 2. Then subtract .001 off that number and you should be pretty close to where you need to be in thrust washer thickness. Ideally you want .001-.002 clearance.



Since I've been doing this a while, and I save all the original thrust washers, I have them ground in .001 increments from .075" through .090"



As mentioned above, the goal is .001"-.002" side clearance on the roller thrust washers. The washers need to be kept as equal thickness pairs, so it can be a bit of trial and error to get it set up correctly.



Once the clearance is set, the pin needs to be welded in place. I use 312 SS TIG rod and make a short weld across the top of the pin in each end. I always let the first weld cool before welding the second end, to help minimize any shrinkage, which could make the clearance too tight.



The worm typically needs to be replaced. They will get galled or pitted on the surface of the worm (usually in the center)



Or have pitting or spalling on the bearing race



I made up a simple driver to press the worm off the shaft





Next up is prepping the steering box housing. I remove the sector seal, press out the bushings and remove the upper bearing race before media blasting. The easiest way I have found to remove the bearing race is to weld a 1/2" flat washer into it. The weld will shrink the race and the washer gives something to tap on with a hammer and drift.




To make that job easier down the road, I usually cut two notches so you can get a drift in and knock the bearing loose. Just trying to make it easier for the next guy.



I have a simple driver made up to press in the upper race. It can also be done with sockets and a vise.



Next up is pressing in the new sector shaft bushings. Again I made up a driver and press them in using a hydraulic press, but the job could be done in a vise.



I then hone the bushings to fit the polished sector shaft. I have a Sunnen pin hone, but this job could be done at any engine machine shop.



It's important to have a good fit on the sector bushings, as a loose sector shaft will take the sector seal out in a short time.



The tube on the end cover is usually loose and a cause of leaks. Both the early version with the br*** tube and the later steel tubes were just crimped in. When dirt and rust would fall down the steering shaft it would wedge in between the tube and shaft, then the tube would start turning with the shaft. The looser the tube gets in the end plate, the more it would leak. I drive a tapered rod through the br*** tube to take out dents and straighten them, then silver solder the tube to the plate.



I then fixture them in the lathe and face the gasket surface, again in an effort to seal up these leaky old boxes.



I find it helpful to lay out all the parts before ***embly, as it is a good time to do an inventory and make sure you have everything prepped and ready to go.

I may seem overboard to some to clean and polish everything, but sometimes you won't see that a part is cracked or damaged until it has been thoroughly cleaned. I'd rather spend the extra prep time to make sure I have good parts.



The first step of ***embly is setting the preload on the steering shaft/worm tapered roller bearings

This is accomplished using a stack of shim gaskets. The kits typically come with 3 or 4 thicknesses of gaskets, and a typical box uses .050-.060" total shim.





I torque the the end cover bolts to 20 ft-lbs. This gives you a consistent read on the bearing load. You will need to add or subtract shims until you get a slight drag on the bearings. Once you are close, adding or subtracting a .003" shim will usually dial it in to where you have some drag, but not so tight that there is a "notchy" feeling in the bearings.



The next step is the install the sector shaft and set the lash between the roller and worm.

I have cut up some side covers, so I have a window into the mysterious world inside the box. I am a visual learner, so it really helps me to see what is going on before sealing a box up and trying to get it adjusted. I've had boxes where the sector shaft will rub on the worm, cover or housing when going to lock. I like to check all that, along with a visual on the roller engagement with the worm.

The sector adjustment is an incremental process similar to the bearing preload. You want to bring the sector roller in so it just contacts the worm. This needs to be done with the box centered. Count the number of turns lock to lock, then come back half way. With a 37-48 Ford steering shaft that has a taper and key steering wheel, you can watch the keyway when you are coming back to center. It is usually about 2-1/4 turns from lock back to center. You will feel a slight drag as you turn the box through center. It shouldn't get tight, but you should be able to feel the worm and roller engage in the center.



And here is a completed steering box






The subject of lubricants often comes up. I like to use NLGI "00" semi-fluid grease. I feel it flows back better than the "0" grade cornhead grease. That's my opinion and you know how opinions and the internet work.


I will also point out that after the steering box is installed, the draglink needs to be adjusted to make sure the steering box is properly centered when going straight. All that work adjusting the steering box will be thrown out the window if its not set up properly in the car.

There are some good resources out there on the internet, such as Mac Van Pelts website:

http://www.vanpeltsales.com/FH_web/flathead_steerngear_adjstmt1937-48.htm

 

What a beautiful presentation.
I happen to have a '40 hanging on the wall, waiting for attention.
The one on my A ch***is is earlier, but I'm not sure of the year.

 

Great pictures, the details you write in will be helpful to a lot of people. I'm sure there will be much interest. Thanks for taking the time to do this. Tech stuff is always great to see.

 

Your work is impeccable. Thanks for sharing your knowledge and expertise.

 

Thanks for putting this thread together!

 

What they said, I fully agree with. WOW!

 

THANKS! A great service to all of us....

 

Really need to do the box in my 41,it's wasted and no amount of adjustment d I es much

 

Very interesting.

 

I’ll ride along. Thanks for doing this.

 

Great thread, I like the cutaway cover

 

Whatever happened to the HAMB Techomatic?

I'm embarr***ed and ashamed by the tidiness and cleanliness of your working space! Fabulous!

Chris

 

Awesome tech,high 5 to you...
I used up 3 def. box's over the years,from late 1950s tell now in my 28A Bobtailede Roadster ,the mid one was a F1 I let water get in,the rust screwed it up so bad,that finding parts I then needed was p***ed doing.< But I tryed to fix it for longer then I should of!! Your tech reminded me of playing FIX IT for too long on old F1. I really did enjoy what you layed out so well.

 

Thank you for sharing your great work! Makes my “rebuild” of an F-1 box years ago look pretty shabby.

 

Very nice, but did you get tired of typing? How did you fix the support tube for the light switch mast? Do the worm gear bearings have preload, and if so how much? Whats the preferred lubricant? Lately a lot of folks are chubbed up about "corn grease" vs heavy oil. I don't even know what corn grease is, I've only been told "...get it from John Deere..." and nothing else. Again, very nice. Oh yeah, nuthin but repect...

 

Thanks for the feedback and as I stated in the original post, I will be adding in more pics and descriptions as time permits. Give me a few days to get this all together. Thanks for your patience!

 

Corn head grease used in John Deere combines used to cut corn, thus the corn head. It's a 0 grade self leveling grease used in the gear boxes on the corn head, slow moving gears under heavy load. The grease is semi solid till its churned up then becomes a liquid. Once the gear box stops turning, the greases levels out and solidify again. Perfect for a steering box since it always levels back out. Cheap also. Automotive CV joint grease, or lawn mower transmission grease is the same grade.

 

Thank you for posting the excellent photos and explanation of how you do the rebuild.
Your work is impeccable and truly exceptional and much appreciated.
Will you rebuild a steering box if requested?
Keep up the great work.
QUESTION: Will the internals of a 1947 Ford steering box interchange with a 1940 Ford steering box?

 

You are way above I could ever hope to be after just step one: polish the sector shaft. How do you do that? Is it centerless grinding?

When you weld the new pin, did you ever consider that only welding one end would be enough? Not a lot of torque on that pin, you basically just need to keep it from rotating.

 

Impressive in all aspects.

 

Great stuff as always!

 

Great post! This looks remarkably like the HAMB of old! I miss that.

 

Yes, I did get tired of typing last night, but came back and filled in some blanks this morning. Hopefully I've answered your questions now.

 

Yes on the internals interchanging. Besides the different length shafts, the internals from 37-48 car and pickup and 48-52 F1-F3 will all interchange.

And yes, I will rebuild steering boxes for others. It's a hobby, not a business, so they get done as time permits.

On your two questions. If the sector just needs light cleanup, I chuck them in the lathe using a copper sleeve around the threads and use 320 emory cloth followed by maroon scotchbrite. That is all that was done to the sector shaft shown above.

If they need more serious cleanup, I can send them to a local grinder to take off .001-.002 in a centerless grinder. I rarely do that, as 37-48 Ford steering box cores have been plentiful enough to just look for a better sector shaft.

As far as welding the sector roller pin on just one end, while I agree that it is probably good enough, it is steering that we are dealing with, so I'd rather error on the side of caution and weld both ends.

 

That box could be in the Smithsonian Museum, just beautiful!

 

You forgot to show us your fixture for pressing the new worm on the shaft. Or is it a proprietary secret?

 

I can't give away ALL of my secrets...

But, I will say the original shafts are about .742-.743 and I've found the new worms are happier pressing on if the shaft measures right around .741", so I usually chuck the shaft in the lathe and take off .001-.002. Otherwise it's darn near impossible to get the new worms pressed on.

 

Great write up Neal! You do beautiful work!

 

I have fond memories of "Tech Week" and always enjoyed rummaging thru the Tech archive as most old timers did. You were always a major player in those battles 20 years ago. This one could have been a winner.
Well done.

 

Thanks for putting together a great tech piece on the steering boxes, Neal. Your work is impeccable and at a standard that we all should aspire to. Few will meet that standard but we can try our best. Mart.