Is there a way to identify the better 3 tooth sector shaft box by the casting # on the housing without opening up the box?I am trying to get someone who has a box for sale to tell me which box he has.

  

Over here most of the 2 tooth sector boxes have a large blind adjuster lock nut that conceals the thread, the 3 roller sector just has a normal flat nut with threaded screw sticking through.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

The sector shaft for the 2 tooth is 1.125" diameter above the spline where the pitman arm sits. The 3 tooth is 1.25" dia in the same location. The OD of the seal is proportionately larger in the 3 tooth box.



If it is a Canadian 2 tooth box most I have seen were mfg by a separator company and have AB___ number cast in the casting.



I have only seen the 3 tooth boxes in converts, crowns or the high end cars and late year cars. The customlines and mainline got the 2 tooth box. The same 3 tooth sector shaft and steering box was used in the 57's. The worm shaft length is different between a 56 and 57

marv

Hey Marvh! Its an American car.Casting # is AF 3550.I would like to get hold of a good used(?) 3 tooth box to replace my 2 tooth box which jams up once in a while.Kind of unnerving when it happens.Is that casting # any help.My engineering to part# cross reference book doesn't go back that far.

  

Mark

If you measure the sector shaft it will tell you if 2 tooth or 3 tooth. The 3 tooth is 1/8" larger diameter than a 2 tooth. 3 tooth should be 1 1/4" diameter. I will check the numbers on my car tomorrow as it has the 3 tooth box.

marv

[quote]oldcarmark (4/25/2011)

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Is there a way to identify the better 3 tooth sector shaft box



Just curious, but is the faster steering ratio on '55 birds due to the # of teeth, or some other component change in later models? Was the 3 tooth upgrade for improved strength/durability at the cost of slower steering?

6 VOLTS/POS. GRD. NW INDIANA

I'm not sure about the steering ratio situation, but 55,56 - 2 tooth boxes had durability issues. They tended to develop flat spots. A friend had a 56 club sedan years ago that had a major flat spot in the box. However, the later boxes incuding the 57s weren't ammune to that problem either, I know from experience. 1958 & later boxes are a resirculating ball design. However,they don't just bolt into earlier models. One issue is the horn design which is totally different...

Paul

There ia listing on Ebay for a completely reconditioned integral type power steering box modified to mount the same as the original 55-56 box.You have to shorten the existing upper shaft and use a coupler to join together like the later model Fords.Pricey though at $600.00 plus shipping.

  

I just acquired a 3 tooth steering box from a 1957 t-bird with a 1.125" diameter sector shaft. Will post pics w/update.











Number on casting is AF-3550-A

I think you are mis-reading your vernier.



If I see correctly the dial is between the 20 and 30 and looks past what would be the 25...more close to 26 so would be the 1 inch on the slide scale plus the 0.26 on the dial so would be a total of 1.260 inches. This would be a 3 tooth shaft. Congrats on the bird part find.



Here is a pic of a 3 tooth I took this AM. The reading I got was 1.2495 which is 0.0005 under 1.25 or 1/2 thou less than 1 1/4 inches.



1.125 equals 1 1/8 inch