Help in Identifying Model A? Rear Axle & Condition

Two relatively easy things to look for on the axle housings (all this is from the Restoration Guidelines and Judging Standards), note that all this assumes that your rear assembly is original, not a frankendiff.

1. Orientation of the welded seam along the length of the axle housing. Prior to Oct 1928 the weld was on the front of the axle housing. Nov 1928 through the end of production the weld was on the top of the axle housing, except that Mar 1929-Mar 1930 some had welds facing downwards.

2. Spring perch ball. Prior to early 1930 the spring perch ball was forged as part of the perch itself. After that the ball and shaft were a separate piece that was welded in. I can't see from your photos which you have. Look for signs of welding on the outside of the spring perch where the shaft would come through.

You can also look at the location of the filler plug on the banjo. Prior to mid 1930 it was centered. After that it was offset to one side.
 
Y-Blockhead said:
Dang it John. You made me get off my lazy azz and go look! :rolleyes: :rolleyes:
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Yeah, I went through all this when I rebuilt my rear end when I put the Mitchell on a couple of years ago. One thing I did learn - diesel does not work as a solvent to clean 95 year old gear lube and grease from inside of the axle housings. I ended up using a combination of Purple Power, mineral spirits, a drain pipe cleaning brush on my drill, and a lot of cussing. Cleaning out those axle housings is probably the nastiest job I’ve done on any car. Next time I’ll take them over to my powder coater and have him bake the spooge out in his big oven.
 
JayJay said:
Two relatively easy things to look for on the axle housings (all this is from the Restoration Guidelines and Judging Standards), note that all this assumes that your rear assembly is original, not a frankendiff.

1. Orientation of the welded seam along the length of the axle housing. Prior to Oct 1928 the weld was on the front of the axle housing. Nov 1928 through the end of production the weld was on the top of the axle housing, except that Mar 1929-Mar 1930 some had welds facing downwards.

2. Spring perch ball. Prior to early 1930 the spring perch ball was forged as part of the perch itself. After that the ball and shaft were a separate piece that was welded in. I can't see from your photos which you have. Look for signs of welding on the outside of the spring perch where the shaft would come through.

You can also look at the location of the filler plug on the banjo. Prior to mid 1930 it was centered. After that it was offset to one side.
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Thanks very much for the detailed info. Based on that it appears a late 1928 production as the well is on top with the forged perch mount.
 

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Ziggster said:
Thanks very much for the detailed info. Based on that it appears a late 1928 production as the well is on top with the forged perch mount.
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When Ford made a change he didn’t toss parts manufactured to the old design, there was a period of overlap where you might find variants. Looks to me like you have pre-early 1930 axle housings paired with a post mid-30 banjo. That’s a pretty wide span for a changeover. Maybe a frankendiff (someone has assembled from parts sometime after factory), possibly related to a gear ratio change? It would be interesting to see what ring and pinion are in that.
 
Ok. Interesting. I forgot the bit about the drain plug location, so being offset, I guess it’s post 1930 as you mentioned. I’m in Canada, so not sure if that might explain any differences, but it wouldn’t be a stretch that someone at some point mixed/matched up different parts over the last 90 yrs. lol!
 
Ziggster said:
Ok. Interesting. I forgot the bit about the drain plug location, so being offset, I guess it’s post 1930 as you mentioned. I’m in Canada, so not sure if that might explain any differences, but it wouldn’t be a stretch that someone at some point mixed/matched up different parts over the last 90 yrs. lol!
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I forgot you were in Canada. I have no idea if what I have said applies to Canadian-built cars.
 
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Went ahead last night and tried to determine what axle ratio I had. I had just installed the Speedway opens drive kit as well as welding the axle to my chassis for mock-up purposes with the rear tires.
It took just over two full rotations, plus another 30 degrees as measured with a digital angle finder. This gave me 2.08:1 which I thought was weird, so checking with Google, it’s AI said I needed to double that number, so due to some error in my part, I likely have a 4.11:1 rear gear ratio which suits me fine since I’m using a Mustang T5 in my speedster build. I still don’t quite understand why Google AI said I needed to double it, and I’m a retired mech Eng. lol! Will need to do some further reading up on it.
A short vid of me counting the rotations on the input yoke while I rotate the tire.

https://youtube.com/shorts/mMXgQdrq3sA?si=Bd-ZA05sdxmazNCD
 

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Did you only rotate one wheel? Remember that a diff allows the outside wheel to travel further than the inside in a turn.
 
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