The Ruckstell Two Speed Axle Part 2

A popular place to put the Ruckstell shifter is in the rear of the floorboard slot that houses the parking brake lever. This allows easier entrance and exit from the car. The Ruckstell supplied shifter places it in the center of the floor board which can be awkward at times.

This guy has way too much going on. Sometimes you need to stop and look at the overall picture, then act accordingly. There are both a Ruckstell and a Warford in this car. I would not even know where to start as far as how many possible choices there are for gear ratio.

Above our Ruckstell axle case is cleaned, old gaskets are removed, and we inspect for cracks, excessive wear, and evidence of shoddy repairs. All looks good!

When we left off last time the innards of the Ruckstell were together and ready to be installed in the housings. Let’s review the list of parts that were replaced in the process:

Hyatt bearings (3 each)

P43 Ruckstell Differential Case Bolt and nut set

P127S Shifter Housing Gasket

P128S Ruckstell Ring Gear Bolt and washer set

P211 Sealed ball bearing

P141 Differential case half

P146 locking sleeve

P158A Shift Lock Assembly

2504S Rear Axle Gasket Set

2518R Ruckstell 40 tooth Ring Gear

2528 Thrust Washer, Brass

2597B-12 Ruckstell 12 tooth pinion gear

We previously rebuilt the driveshaft. Here’s a link:

Rebuilding the Drive Shaft

Any time a Model T is equipped with an aftermarket accessory transmission or two speed rear axle there is a danger of losing the connection between the transmission and the rear axle. We recommend that any Model T that is modified with any of these accessories also be equipped with some sort of aftermarket brakes. Here is a link to our story on installing Rocky  Mountain brakes:

Installing Rocky Mountain Brakes


We slide the assembled differential and axles into the Ruckstell housing, taking care to make sure the notches in the P147 Gear Locking Notch Plate align properly with the locking bolt holes in the case.

Our friend Nolan has a cutaway rear axle housing that makes it very easy to see what the mesh is when working on Model T rear axles. We assemble the drive shaft and the Ruckstell rear end with a few bolts and support the whole thing upside down on jack stands so that we can see and measure the gear mesh.

This picture does not give you a good image of what to look for, but the good news is that the ring gear and pinion are perfectly aligned with regard to depth. The gears are coated with grease so that we can see the pattern on both sides of the gears. Mesh pattern is excellent. Clearance is less than .010″ and more than .002″ so it is acceptable. The pinion gear nut and cotter pin are not interfering with anything.

We start working on getting all the parts ready for final assembly. The radius rods had a light coat of surface rust on them We used a Dotco high speed angle air motor with a wire wheel to make quick work of removing the rust.

Notice how the threads are worn away where the radius rods went through the loops on the drive shaft. The nuts were probably loose for decades. This won’t be seen when the unit is assembled, and there are plenty of threads to hold everything firmly in place.

Ready for primer. We take them outside for a coat of red oxide self etching primer.

The right side axle housing has the 2529 steel thrust washer installed with a coating of The Right Stuff which is allowed to cure overnight. This secures the thrust washer to the axle housing, making assembly much easier. We install a new housing gasket using 3M 021200-21185 Green 30NF Fastbond Contact Adhesive. With that, we start to assemble our Ruckstell. The RH inner Hyatt bearing is greased and the bronze thrust bushing is also coated with grease and put in place against the inner steel thrust washer at the differential case. We take the drive shaft out briefly, install the radius rods and then everything can be bolted back together for the final time. Silicone sealant “The Right Stuff” is used on all the gasket surfaces to prevent some of the typical Model T oil leakage.

Above the radius rod bolts get cotter pins. Earlier we replaced the bushings on the parking brake cam shafts. That job will show up in a future article.

A tape measure is used to measure the distance from the center of the forward drive shaft bushing grease cup to the center outboard tip of each axle shaft. The nuts on the radius rod arms are adjusted until the two measure exactly the same.  The result is a Model T that tracks straight down the road. Far more threads show forward of the nuts on the left radius rod because of this critical step in the assembly process.

Arrows point at the two special screws used to index the P147 Shift Lock Plate.

Above, accessory grease seals are used to keep the grease in our Hyatt bearings and away from the parking brakes. The arrow points at the spring perch nut. These need to be left loose until the rear axle is installed. They need to be tightened and then the cotter pins installed upon installation in the car. If they are tightened now, no doubt they will not align properly.

It’s all together now, and we prepped it for paint using sandpaper, the wire wheel, and elbow grease. Unfortunately our paint booth is outside in the back yard where it is 36 degrees F and raining so we will just have to wait for better weather.

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