Posted on by Royce Peterson

Swapping a Rear axle on the Model T Ford

A huge fallen Sequoia tree in what was then known as General Grant Park provides a nice backdrop for a Model T photo in 1914. Today the park is known as Kings Canyon National Park. 

We built a replacement Ruckstell axle for our Model T a couple years ago. See the articles here: https://modeltfordfix.com/the-ruckstell-two-speed-axle/ 

Finally the time has come to install it. The Ruckstell axle in the car worked fine, it has the standard 3.63:1 gear ratio. The axle being installed has the optional Ruckstell ratio of 3.25:1.

We started the job by jacking the rear of the car about 6″ off the ground. We supported the frame just forward of the radius rods using tall truck jack stands.
Meanwhile, another set of jack stands was placed under the rear axle to compress the rear spring.
The floor boards were removed, and the brake lever was released all the way forward.
Next, we pulled both rear wheels. If your car has wooden wheels you won’t need this step.
We removed the hubs next. If your car has wooden wheels the hub comes off with the wheel.
With the brake drums and hubs removed we can strip away all the brake pieces so they can be transferred to the new rear axle.
The LH side gets stripped of its parts next.
With all the brake parts out of the way we remove the cotter pins and nuts from the spring perches.
The axle is still supported by the jack stands.
Next we removed the four bolts from the ball cap that secures the universal joint to the transmission. Oddly, there was no safety wire on the lower two bolts. Hmmmmm.
It turns out those bolts didn’t have holes for safety wire. We drilled each bolt 3/32″ so they could be safetied upon installation. 
The rear axle is slightly jacked up so that the jack stands could be removed.
As the jack is lowered the spring perches pull themselves halfway out of their respective backing plates.
Just a touch with your finger pushes the spring perch out so that the rear axle can be withdrawn.
We slide the rebuilt Ruckstell axle in place. The universal joint is completely packed with grease. The outside of the ball is also smeared with grease. There is no gasket. We make sure the grease fitting hole is “up” and install the four bolts loosely.
The axle is jacked enough that the spring perches can be installed into the backing plates. Then the nuts are started, and the jack stands are placed under the axle.
With the axle in its final position the spring perch nuts can be tightened and cotter pins installed.
The backing plates are “dressed” with their brake parts.
Finally the hub and drum can be installed.
With the LH side done we moved to the right side for more of the reassembly process. It was raining off and on so I had to move the other car inside and close the garage door, leading to the dark photos you see in some of the images.
The RH side is buttoned up and ready for its hub / drum to be installed.
Up front we tightened the four bolts on the ball cap. The upper two get cotter pins, the lower two bolts are safetied with .041″ aircraft safety wire. The grease cups are installed, and the Ruckstell linkage connected.
One of the shortcomings of Rocky Mountain brakes is that the brake rods rattle like crazy. We made some anti – rattle brake rod supports from 1″ X 1″ aluminum L-angle to combat this. They bolt to the Ford brake rod anti – rattlers with a single #10-32 bolt.

With the rear axle installed we filled the Ruckstell with SAE 85W-140 rear end lubricant and removed the jack stands. A drive around the neighborhood confirmed the newly rebuilt Ruckstell axle was quiet and performed well.