VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc late 30's / Early 40's rear end centering - front to back - is it normally too far forward?

Hello folks -

I am thinking about taking my first leap into pre-war Chevrolet, specifically something like a '41 Coupe, and I've come across an odd potential issue with rear axle alignment, and I am hoping you can assist.

As you do when "shopping" I've looked at several cars and in some cases I'm finding that the rear axle seems to be perhaps 1.5 - 3 inches too far forward. As I am also looking for cars with adapted running gear, I imagined this may be due to the use of a later model rear end, but, I've found the same issue even in stock cars - but interestingly, not all - so its inconsistent.

Here are examples of what I mean:
This car, a '41, has a later year 8.5" rear end, so I first assumed the modification was the cause....

[img]https://drive.google.com/file/d/1w88irCiMgRYeg4lKulSaVlNF8h72ILBS/view?usp=drive_link[/img]

But then I found several examples of stock cars of similar year, with the same problem:

[img]https://drive.google.com/file/d/1uqlz0GWss-9aAlwuN4KIYtV7rJs0Tv22/view?usp=drive_link[/img]

[img]https://drive.google.com/file/d/1ebmbex4bmOs4SXg3bjG1i84wqBtkj2Xi/view?usp=drive_link[/img]

[img]https://drive.google.com/file/d/1wd9lzRBXsaeTBE30MGUvVr_1l3t_SZxC/view?usp=drive_link[/img]

The black car pictured first is a potential purchase (the others may or may not be, I forget which are actually for sale) but do I need to be concerned about this "rear axle forward" condition? and.....since it sort of looks a little goofy, is there an adjustment? (aside from welding on new perches, etc)

Appreciated,
Allan.

My 36 master also has the rear wheel slightly forward in the wheel opening. The car was never modified only worn out. I have not looked for this condition on my 41 coupe. My 57 truck wheels seem balanced in the wheel opening.

When the rear end is jacked up it is normal to see the wheels be farther forward,
Ths is due to these modes have fairly short rear spings.

If a later open driveshaft rear end is installed. And they used the original pilot hole on the axle perches, it moves the axle ahead about 1.5 inches ahead of the fender opening. To center the the rearend, a new pilot hole needs to be drilled 1.5 inches ahead of the open driveshaft pilot hole.

Thank you for the replies.

I know some of the cars I included were stock, but certainly the black one has probably a mid-70's 8.5" rear end. I am not really that familiar with the rear axle, so I'll need to do some research on drilling pilot holes - is this the sort of thing where you need to weld something? I have a welder, and technically can weld....but I'm more an exhaust / floor welder that a "critical suspension connection point" welder .

If you have a spring and axle shop close by you can take the vehicle to them, tell them what you want, give them a few days then write a check & take it home. They usually have all the expensive equipment needed to do any suspension job. While they usually work on big trucks I've never seen or heard of one turning down work.

Thanks all -

Sounds like this is easily correctable. First step though is to find a car!

Here is a picture of how the wheel is in my 1941 Master Deluxe. I have a fully stock drivetrain and the stock tire size. There is no weight in the car when this photo was taken.

I am guessing that they were designed to look right with a normal load of passengers, fuel, and cargo. Sitting empty they do look a little jacked up and out of center.

Dave

Would the original design using torque tube and only a joint at the transmission end have anything to do with this? The lower the axle drops the further forward it would have to move.

...YES...