August 10th 1938 – the chassis build date – Update # 20

Steve has disassembled the rolling chassis and, in doing so, has discovered an important date in the Diamond T tanker’s history.

Dismantling The Chassis

With the Diamond T cab being repaired at Creative Metal Works, Steve began the task of stripping down the chassis.

He removed the driveshaft, engine and gearbox, front and rear axles, fuel and brake lines and the brake and clutch assembly. Also taken off the chassis was the remote brake booster, springs and shackles, side strengthening plates and the hardwood beams that sit between the chassis and the tank.


Steve utilised the forklift once again to chain lift the Hercules CBJXD engine and the 5-speed transmission from the chassis frame.


The wooden beams were still attached to the top of the chassis rails in this image.

These timber lengths were used under rigid bodies to accommodate the movement and allow the frame to flex as necessary. Today, this system has been replaced with separate ‘resilient’ mounts that are either spring loaded or made with rubber or polyurethane elements.


Another view of the timber beam. Wooden blocks are also fitted at intervals along the inside of the rails.


The brake and clutch assembly.

The Front and Rear Springs

Once the springs were removed, Steve found one of the front top leaves was broken so he delivered the front and rear springs to Archer Auto Springs in Takanini. The team at Archers not only replaced the broken leaf, but also stripped both the front and rear springs for inspection.

Both rear springs were in surprisingly good condition, considering the load that they carried over the many years in service.

New centre bolts were fitted to all the springs, and the top and second leaf on both front springs were replaced. New u-bolts were also manufactured.

Archer’s recommendation to Steve was that the leaves should not be blasted individually. So the springs were reassembled, and these will be blasted and two pack primed as complete units.


The reassembled springs. The replaced top and second leaves are noticeable on the front springs.


The manufactured u-bolts.

The Chassis Build Date


The bare chassis was lifted and secured on the trailer, and then brought home prior to being delivered for sand blasting the following week.


Steve and I were standing by the trailer that weekend chatting with Tom Andrews when Steve noticed some pale red paint on the chassis where the fish plates had been. He cleaned the area with some engine degreaser to reveal a number –


August 10th 1938

As we were studying the number, we realised that it had been stencilled on to the rail upside down, as the chassis was laying on its back on the trailer. Once upright, the build date would have been displayed on the left hand side of the truck.

We sent a photo of the number to Steve Rutledge in Texas, who has an extremely vast knowledge of Diamond Ts. Steve Rutledge believes the second set of numbers ’32-63′ is most likely a production number.


The survival of this painted number after 80 years was due to the steel strengthening plates or ‘fish plates’ providing protection from the elements. There were also patches of the original black chassis paint in quite good condition along the length of the fish plate area.


Chassis Number 6140330

After discovering the build date, we went right over the chassis and found the chassis number engraved on the opposite side. I have flipped this image as the number appeared upside down while the chassis was still overturned. Once upright, this number will appear on the right hand side of the truck.

We came so close to missing the stencil painted build date which was about to be lost forever. I took a number of photos that afternoon to show the position of the stencilled number and to record it as part of the tanker’s history.


The Fish Plates

Attached to each side of the chassis rails are heavy gauge lengths of steel, called fish plates, that add strength and rigidity to the frame. These were fitted to the heavy-duty truck chassis during construction.


Both plates had sustained damage to the lower edges that protrude past the chassis rail. Steve was able to press them back into shape to use them as a pattern, and replacement plates were guillotined out of the same gauge steel.


Steve then transposed every hole from the original plates on to the replacement ones.

The hole positions are not mirrored exactly on both plates, with the left plate accommodating the brake and clutch assembly.


Both plates have been test fitted to each side of the chassis to ensure the hole placements are absolutely correct.


Steve has now painted the plates with Epotec two pack epoxy primer, and these are ready to be riveted back on to the chassis once painted.

The Rivets

The system used to secure the fish plates to the chassis was a number of heavy-duty, forged rivets joining the surfaces of steel together. Twenty rivets per side to be precise!

Wanting to replicate the same fixing system, Steve contacted Greg at G R Engineering on the North Shore. Greg was able to source and supply some new, old stock rivets of the same diameter.


1/2″ x 2″ solid round head steel rivet


The 2″ length is longer than required so each rivet will be cut down to the correct size when Steve reattaches the fish plates.

The Chassis Paint Preparation

To strip and prepare the frame for painting, Steve delivered the chassis to River Road Blast & Paint in Horotiu.

There it was sand blasted back to bare steel and then painted with Epotec two pack epoxy primer.


Once the chassis was back home again, Steve made up a rotisserie using two engine stands. This set up provides a good working height and also enables the chassis to be moved around quite easily.

The next step will be to paint the fish plates and the corresponding areas on the chassis rails so that the plates can be re-riveted to the frame. Once this is done, the chassis will be ready for the finishing coat of paint.



Rebuilding the Diamond T cab – Update # 19


Two roofs, one cab – Update # 21


  1. David Fordham

    Why did Archer recommend not blasting the spring leaves individually?

    I’m really enjoying the restoration of this Tanker. Thank you for sharing the process.

    • Sue Keys

      Thanks David. Archers felt that sand blasting each leaf could possibly have a shot peening effect which may alter the tension of the springs.

  2. CJ Rogers

    Wow, the thoroughness and detail of this mammoth project is just awesome. Beautifully documented Sue, I look forward to each update

  3. Gary Butt

    Cool Project, look forward to watching progress.

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