1. Remove the floorboards.
  2. Unscrew the floor panels behind the pedals and remove them.
  3. Unscrew floor support bracket and remove it.
  4. Remove bolts from pedal linkages.
  5. Remove cross-shaft.
  6. Split the clutch and front box joints.
  7. Remove the propshaft.
  8. Remove the clutch springs.

The clutch should now slide out of the flywheel. Reassembly is the reverse, although remember the following:

  1. Oil the clutch on reassembly.
  2. When reinserting the propshaft have both springs and the clutch slippers held onto the knuckles with a dab of grease.
  3. Insert the clutch knuckle first presenting a plain edge of knuckle into the box joint first (rather than a slipper edge).

Machining Boxjoint Slippers

See page on Machining Boxjoint Slippers.

Removing and Splitting the Middle Boxjoint

  1. Remove the bolts (there orientation is important, mark it!). Some of the nuts will not move past the machined slots in the boxes and will have to be loosened and tapped back until they willl move through further.
  2. Slide the boxes back from the disk making sure you do not loose the slippers from inside. The orientation needs to be marked.
  3. The centre disk has two springs which push against each of the knuckles. Remove the disk with the springs.
  4. The boxes can now be removed. They will just fit through the gap between the knuckles.

If the box joint is going to be off for any time it is recommended that you reassemble the boxes on the desk.


See page on The Gearbox.

Removing the Transmission Brake

  1. Mark the orientation of the universal joint spider assembly.
  2. Loosen the pinch bolt on the UJ pivot.
  3. Suspend the propshaft between the transmission brake and the differential using a piece of rope or a belt from the pump propshaft.
  4. Remove the split pin and castellated nut from the UJ pivot. It should now be possible to remove this shaft, followed by the other and the remove the UJ spider. (The shaft held in with the pinch bolt is also secured by the other shaft engaging with a notch in it).
  5. Remove the split pin, castellated nut and washers from the gearbox output shaft.
  6. The transmission brake can now be worked off the gearbox output shaft carefully with a rawhide mallet.
  7. There should be just enough clearance to remove the transmission brake if the brake and propshaft are orientated correctly.

Removing the Rear Propshaft

  1. Empty the main box and take out the floor boards.
  2. Start by jacking one (rear) wheel off the ground so you can rotate the wheel.
  3. Unhook the speedo belt from the spring loaded pulley and leave it hanging on the propshaft.
  4. The universal joint has two drive pins (~8″ long) that you need to remove. One has a big nut on the end that you need to remove.
  5. The other has a notch halfway along it, which meshes with the first pin to prevent it falling out. It also has a pinch bolt on the red drive spider. Move this bolt untill the second pin becomes loose.
  6. Manoeuvre the propshaft to remove the spider (center of UJ).
  7. Rotate the rear wheel untill the prophaft lines up in a good position to remove it.

Removing the Rear Box Joint

  1. Undo all the nuts on the box joint.
  2. Split the box joint and move the propshaft out of the way.
  3. Remove the box joint housing.
  4. Undo the pan head screw and locking nut (special tool).
  5. Remove the box joint knuckle, slippers and keyways.

Removing the Worm Gear

To remove the worm gear:

  • Take front an rear plates off the diff.
  • Use pusher form the back to push out worm gear.
  • Take off TOP HAT – and disassemble thrust bearings.

To replace the worm gear:

  • Put the worm gear into the diff with a pregreased front bearing.
  • Bolt on the “TOP HAT” hand tight and use the pusher on the front of the worm to push fully in.
  • Put the front plate on tight (with gasket).
  • Take off the TOP HAT – Assemble Thrust Bearings in TOP HAT with the final externally threaded piece located such that the locking nut on the bottom can be put in. Put gasket on the TOP HAT.
  • Hammer TOP HAT on using metal plate – until the pusher can be used with the “metal disc”.
  • When the “metal disc” hits the end of the axle use a piece of steel piping to push the TOP HAT all the way on.
  • Bolt on the TOP HAT – and screw on the final plate.
  • Fill up diff with grease.

Differential Specifications

  • “Dennis Patent Overhead Worm Drive Diff”
  • 4.85-4.45 17/02/1916

Rear Wheels

See page on Rear Wheels.


Ben’s CAD drawing of Tyre in pdf format.