Model A Rearend
- Thread starter yohoc1
- Start date
31Tudor
Well-known member
The best way is to purchase the Model a Restoration Guidelines and Judging Standards. The basic Model A rearend is pretty much the same throughout production, as far as the overall look and function. However, there were many changes: adding shock balls, the welds on the left and right housings changed as to where they were located, the placement of the fill and drain plugs changed, the backing plates changed, the two rear radius rods changed. You can see there are quite a few variables as to what specific year. The restoration guidelines show in detail the month and year all of the changes that were made.
Big hammer
Well-known member
If you can post pictures, I'am sure we can help you!
Bob Bidonde
Well-known member
Noticeable rear axle housing changes are:
>About mid-1930, the location of oil fill plug on the center section moved from the center of the housing to the left as viewed from the rear of the axle;
>The weld seams on the axle housings face forward thru March 1929, and the welds face down for the rest of production;
>In 1930 &'31, the shock absorber balls were separate parts riveted into the spring hangars.
>About mid-1930, the location of oil fill plug on the center section moved from the center of the housing to the left as viewed from the rear of the axle;
>The weld seams on the axle housings face forward thru March 1929, and the welds face down for the rest of production;
>In 1930 &'31, the shock absorber balls were separate parts riveted into the spring hangars.
Last edited:
Mikeinnj
Well-known member
Read Tom Endy's rear end rebuid seminar.
Follow this link....http://www.santaanitaas.org/wp-content/uploads/2014/08/Differential-Rear-End-Restoration-Revised-2014.pdf
Follow this link....http://www.santaanitaas.org/wp-content/uploads/2014/08/Differential-Rear-End-Restoration-Revised-2014.pdf
Tom Endy
Well-known member
The early cars had a different constructed ring & pinion and also a different gear ratio. See the attached article. There is also an early and late ring gear carrier. The later spider gears also have oil holes drilled in them.
The thickness of the gasket between the axle housings and the banjo was changed from .006 to .010 because of oil leaks. This required changing the depth of the bearing race stop in the axle housing and it has been a source of confusion over the years for people trying to overhaul a rear end when it comes to setting the carrier bearing pre-load.
During the Model A production run a number of changes were made to the four housings that comprise the rear end. However, they are all interchangeable and in the years since many surviving Model A's today have a hybrid rear end installed with a mix of housings from all the production years.
This is because after more than 90 years most rear ends have been apart numerous times and housing components replaced without regard to correct year.
In 1929 some, but not all, axle housings had the seams on the bottom. The 1928's had them on the side and they will face forward or aft depending which side you put them on. They can go on either side and the the correct orientation is strictly a judging standard issue. The later axle housings have the seams on the top.
The early banjos did not have support gussets around the torque tube flange and they were prone to crack. During an overhaul I generally replace an early banjo with a later, unless the car is going to be judged. The very late banjo's have the fill plug on the left of the center line. The idea is so you can peek in and see the condition of the gears. Good luck with that one.
The torque tubes are all interchangeable. There are slight differences in the shape over the production run.
The judging standards are the best source to determine the year of each housing component that makes up the rear end.
Tom Endy
The thickness of the gasket between the axle housings and the banjo was changed from .006 to .010 because of oil leaks. This required changing the depth of the bearing race stop in the axle housing and it has been a source of confusion over the years for people trying to overhaul a rear end when it comes to setting the carrier bearing pre-load.
During the Model A production run a number of changes were made to the four housings that comprise the rear end. However, they are all interchangeable and in the years since many surviving Model A's today have a hybrid rear end installed with a mix of housings from all the production years.
This is because after more than 90 years most rear ends have been apart numerous times and housing components replaced without regard to correct year.
In 1929 some, but not all, axle housings had the seams on the bottom. The 1928's had them on the side and they will face forward or aft depending which side you put them on. They can go on either side and the the correct orientation is strictly a judging standard issue. The later axle housings have the seams on the top.
The early banjos did not have support gussets around the torque tube flange and they were prone to crack. During an overhaul I generally replace an early banjo with a later, unless the car is going to be judged. The very late banjo's have the fill plug on the left of the center line. The idea is so you can peek in and see the condition of the gears. Good luck with that one.
The torque tubes are all interchangeable. There are slight differences in the shape over the production run.
The judging standards are the best source to determine the year of each housing component that makes up the rear end.
Tom Endy