Help with 7 tooth steering rebuild
 

I am in need of some help rebuilding my 7 tooth steering box. Disassembly was pretty straight forward but now I am not sure how to approach the rest of the rebuild. Looking at the pictures I bet you cannot guess what kind of lubricant was used by the previous owner. Hint, it was not oil. I imagine I need a new worm and sector gear, but I am not sure what to do about the steering shaft. The shaft is chewed up above the worm gear, can the shaft be built up and turned back to specs? I am also wondering about the bearings, as you can see in the picture there is a lot of clearance between the bearing and shaft. Same with the shaft and lower bushing, the clearance at the bushing is due to wear from no lubrication, but I cannot see the bearings wearing like that, are they the wrong size? Do the bearings sit on the knurled part of the shaft?

I would appreciate any insight on how to approach this rebuild. Thanks for your time.

Re: Help with 7 tooth steering rebuild
 

The shaft can be built up and turned down, on the shaft on both sides of the worm gear. I've repaired several this way myself. The roller bearings are a loose fit on the shaft, they are for thrust load of the shaft as it tries to pull and push itself against the sector. The centralising loads are performed by the bushes. When you fit the end cover with the lower bush, you add or subtract shim plates until there is minimal up and down movement of the steering shaft, without making it stiff to turn.
With my shafts, I turned the lower end of the shaft where the seal runs to 5/8, and then turned the end of the end cover internally to receive a 5/8 chevron seal. You can then run the std seal nut and it will last longer than the original seal and externally looks standard.
You will need a new sector. The teeth should be parallel along their faces, and yours have worn to an hourglass shape. This will cause a lot of slop in the steering, and it can not be adjusted out on the seven tooth.

Re: Help with 7 tooth steering rebuild
 

Another suggestion is to get the steering column no leak tube which will prevent leakage from the bottom of the seven tooth box. You will have to clean the inside of the steering column shaft very good as it is usually filled with crud. Lacquer thinner and a .38 caliber bore brush work great for cleaning it out.

Re: Help with 7 tooth steering rebuild
 

Is the 7 tooth that is in the early 28 that does not have a bail on the light switch the same as all other 7 tooth boxes

Re: Help with 7 tooth steering rebuild
 

try this link:
http://www.maurer-markus.ch/ford_a/m...saeule.en.html

Re: Help with 7 tooth steering rebuild
 

Snyders sells a 7 tooth sector that is said to be made to Ford exact spec. part number A-3575-B. Bratton sells a new steering shaft with the 7 tooth style worm gear already installed part number 4900 . At $225.00 its kinda pricey but in my opinion is cheaper and less hassle than paying shipping two ways when having an old shaft fitted with a new worm gear. It may also be difficult finding a place to turn down the end of the shaft for an undersized bushing. There is also a big risk of bending the shaft when tring to press on a new 7 tooth worm gear .

Re: Help with 7 tooth steering rebuild
 

Luckily the 7 tooth worm is not as snug of a fit to the shaft as the 2 tooth. I have not used a press for the worms to this point. A block of wood and a piece of pipe is all that is needed to remove them after the lock ring is removed. Rod

Re: Help with 7 tooth steering rebuild
 

Thanks everyone for your responses, I really appreciate it!

Dave, thanks for clarifying about the bearings, I would have never guessed and would have probably sent the new bearings back. Also thanks for confirming the need for a new sector. When I started taking it all apart I debated on if I should even do it as I did not know what kind of wear to look for as I am not even sure what it is supposed to look like when it is correct.

Al, thanks for the link, that site is a great reference for the rebuild. Elliot, I definitely want to use the tube you referred me to, thanks!

Purdy, that $225 is pretty pricey, however it is good to know about as one of the suppliers told me they are not available anymore. I might end up going that route though as you weren't kidding about it being difficult to find someone to work on the shaft. 5 of the 7 machine shops in my area do not do that kind of work and the 2 that do are somewhat reluctant. They were concerned about welding on a steering component, that and not knowing the metal composition they feared that welding it could jeopardize the integrity of the metal. I am glad they have foresight, but is it a valid concern since we are just building up a bushing surface? It was also suggested to braze or silver solder the surface, but I do not think it would be hard enough to hold up, any thoughts? Dave, did you do or use anything special when building yours up?

Thanks again for your help.

Re: Help with 7 tooth steering rebuild
 

As you are building over the top of the existing shaft with weld, and not joining two shafts together, the chances of failure dramatically drop. I used a MIG welder to do my build ups. It doesn't need to be a hard wearing weld, as it is in a bush, which is softer than the weld so the bush will wear before the shaft. If you do weld the shaft and turn it down, do not use a 3 jaw chuck, as they do not centralize well. If you start from scratch, they are OK, but trying to turn something to an existing centre requires a 4 jaw and a dial indicator. I set mine in the 4 jaw using the worm as the datum. This ensured that the surfaces that were being turned were on the same axis as the worm. If they are not, as you turn the steering wheel, the worm will move toward and away from the sector, giving you loose and tight spots, and may even almost jam up.
I think brazing would be OK, but it will generally be only as herd as the bush, so would most likely wear at the same rate. Silver solder would be to soft.

Re: Help with 7 tooth steering rebuild
 

Thanks Dave! Do you by chance have any specs for the steering shaft? I took it to a machine shop and the machinist noticed that the area where the lower housing bushing sits is slightly larger than the rest of the shaft. I figured it was just ridges from the grooves, but a small area immediately above the worn area is indeed slightly thicker. It measures 0.817-0.818" while the rest of the shaft is 0.815-0.816". If it is not supposed to be thicker, then he thinks he can just smooth out what is there. That would be great as it would save us some work, but unfortunately the lower bearing bushing still needs help as it measures in at just 0.575".

Re: Help with 7 tooth steering rebuild
 

The shaft above the upper bush area is a slightly smaller diameter than the bush area itself. This allows the shaft to be passed through the bush easily, then only the area that runs in the bush is the correct size. The size of the shaft varies between .796" and .810". The area for the bush was .818". This is slightly larger than 13/16, or .812". I made my own bushes to fit as well. I have a lot of steering columns to pick through, approx 30, to get measurements and to compare to each other.
With the lower bush, it sounds like you need a serious build up. I turned mine to .625", which is still smaller than factory. All mine were worn and grooved from dirt, so I could not get an accurate measurement of what they should of been. I turned them to .625" as it a a common size for a chevron seal, and then also turned my own lower bushes to suit the smaller size.