Adjusting Jacox steering box on 1927 Pontiac

[Gunsmoke]

Been helping a friend restoring a nice '27 Pontiac Sport Coupe, and today we tackled the steering. This model has a Jacox steering box, which I am not familiar with as my '31 Chrysler and '31 Chev have more conventional worm and sector gear. The Jacox box uses complex worm gear integral to steering column/shaft and split "nuts" (or 1/2 nuts) either side which move forwards or backwards as shaft is turned, thus pushing a yoke style pitman shaft at bottom of box. We have no material on the steps and sequence needed to get everything centered, steering wheel and drive wheels in correct alignment, and procedure to get rid of play. End play for steering shaft is easy, they use an adjusting collar and pinch bolt much like Chevy/Chrysler. However we need to know where steering shaft should start, i.e. where should keyway in steering shaft be pointing, 12,9,6 or 3 o'clock. With that determined, next quextion is just where on the worm the split side nuts go, appears they can be placed in at least 4 places on worm (closer to bottom end or closer to top end), as well as flipped (which makes wheels turn in opposite direction to steering wheel!). Box as is was assembled by unknown party several years ago and so we are about to disassemble it in next couple of weeks. We do not know if yoke is in correctly, etc. Best we could do today was get reasonably free steering, but with 3" of wobble at front wheels, (1/4" wobble might be tolerable?). Lock to Lock varied from 1.5 turns to 3.25 turns, we assume about 3 would be correct. Anyway, if anyone is familiar with these, please offer advice, and if there are any service advisory's or diagrams showing proper setup, please let me know. I believe these were used on some early Buicks and other cars. Thanks  

[hwellens]

See if this helps: This is from a 1920 book

 

Dyke_s_Automobile_and_Gasoline_Engine_En 713.pdf

Edited June 26, 2016 by hwellens (see edit history)

[Gunsmoke]

First time I have seen an illustration. Unfortunately not much detail/advice offered on servicing/assembly etc. While they seem like a fairly straight forward mechanism, appears lots can go awry. Guess that's why they advise "only take apart as a last recourse"! Thanks 

[Guest]

Your explanation of adjusting this box is essentially the same as the 1927 Operators Manual that I have.  A slightly more detailed description is in An automobile steering gear book put out by International Textbooks.  There does not seem to be any information about reassembling.  However one illustration looks to put the keyway for the steering wheel at 12 o'clock. The book also says that this gear was used in Viking, Marquette and Buick prior to 1930.  MIght give you some other places to look for information.

Edited June 27, 2016 by Guest
more information (see edit history)

[bradsan]

This is for a Buick Jacox box. I think there is some info on setting up the play in the box at the end of the article.

Thanks go to the 1927 Buick group on Yahoo!

 

Brad

_Procedure for Reconditioning Buick Steering BoxMK 3.doc

[Gunsmoke]

Excellent reference, it should help a lot in assessing what we need to do. The advice that the hardened end caps may need removal and adjusting for smoothness/wear and shimmed accordingly is not something we would have ever discovered on our own. Sounds like something we can handle. Many thanks, will let you know when we have success!.