I'm trying to pick which pitman arm to use and I noticed I have 2 different arms with slightly different angles. I assume this change was due to the different steering column angle and that the 26/27 arm would be the 2 on the left with less of a bend, anyone know for sure?
East test Dave, just compare them with the one on your Tourer. The one that matches will be the one to use!
I did get under and check the Tourer, but I like to double check. Too many things have been changed on that car over the years.
I asked this question a while back, The 1928 parts book only shows one arm, 3547B which would be used as a replacement for 1909 to 1927 for all cars and TT. The illustration in the parts book is not of great help but the ones on the left are at least close.
If I read that part number correctly, there were only 3 revisions, 3547, 3547A and 3547B.
The 26-7 part are the two on the right of your pic. The original parts books never assigned a new part number when the change was made, but the factory number in the far right column is different.
The change was made to make up for the lowering of the front end when Ford took 1" out of the arch of the front spring and to prevent the draglink from dragging on the wishbone.
I just looked at my 1921 parts book and it's listed as 3547 (929B), the 1928 list it as 3547B (929C). I am working on a 26, it has a 25 and earlier front assembly under it now so I will be looking for the correct pitman arm before I put the correct spindles on it. I enlarged the photo and compared it to known 1921ish arm, it's the same as the two on the left, this will help so I can compare it to the one I need. This has been a help, thanks.
If you ever don't have access to a sample arm, here are the dimensions and changes (from Ford engineering drawings):
1909: A= 2-1/8"; B= 3-1/2"; keyway is 1/8" x 1/4"
1910: A= 2-27/32"; B= 4-1/2"
1912: keyway is 9/64" x 1/4"
1917: A= 3-11/32" (this drawings shows the arm to have an oval shaped cross section)
1922: cross section changed to pronounced diamond shape
1926: A= 2-15/32"; B= 3-1/2"
Interesting note: 1927 parts book shows T-929C (the last type) as being used 1909-27.