Building the rear suspension

With the de Dion in place, I positioned the dampers and loosely bolted them in – top bolt to chassis and bottom bolt to the de Dion. It’s a metric bolt at the top, which should be factory-fitted in the chassis and an imperial in the bottom – all the threads on the de Dion appear to be imperial.

Levering out the caps on the diff was the next job. Key to this is where you get purchase. I found they moved quite easily when levering under the dust covers – anywhere else and they appear to be solidly positioned.

I then re-constructed the ear – hub assembly, only this time with the drive shaft through the ears and hub assembly, and stuck the brake disk on the outside of it.

I had to compress the driveshafts and hubs slightly to get the brake disk into position sufficient to get the hub nuts started, but once I’d compressed it by a few mm, I could think about getting the calipers and pads into position. And that’s when I hit a snag – or actually two.

One of the calipers had the piston slightly rotated such that the protrusion in the pad carrier would not sit nicely in it – the pad wanted to jump out of position with the slightest knock. Both calipers had the piston sitting proud, meaning the pads when located in the caliper bracket sat too close together to fit over the brake disk. As both calipers were the same in this regard, I convinced myself I was doing something wrong. I turned to my support network: family experts and the Caterham Therapy Group (CTG). And also Derek of course, just to be sure I wasn’t being a numpty. All came back with the suggestion to rotate the piston clockwise while pushing inwards and the piston should move back, providing space for the pads, and allowing me to align the notches in the piston correctly. I should be able to do this with long nose pliers or grips.

The pistons would not move, despite my efforts with pliers, grips and screwdrivers. At this point in my searches for help on the internet, I came across piston rewind tools which are usually used when replacing pads to retract the piston, pushing the brake fluid back up the pipe. I found one on Amazon for £7. A couple of days later it arrived, and the next morning, on the kitchen table, I sorted both calipers in two minutes. The right tool for the right job – a lesson learned.

Once I was over that hurdle, it was a simple, if fiddly task to bend and fit the copper pipes to the calipers. Thanks to Robin of the CTG who suggested judging the mid-point of the caliper travel and bending the pipe to this location to minimise stress on the pipe over the lifetime of a pad.

The final stage of the build was the fitting of the radius arms. As the de Dion is suspended from the dampers and nothing else, the radius arm prevents any forward/backward movement of the suspension. I don’t have a rear ARB or Watts Linkage to fit as these are non-standard on the ‘S’ model. I decided to fit the arm to the lower of the two possible positions, meaning it is closer to horizontal. I understand there is some difference between the two potential locations, but will I be able to tell? Perhaps once I am out on the road I’ll experiment with the alternate position, but for now, lower it is.

The upper location has a hole drilled through the interior panels, but on my car, the lower position was obstructed by an interior panel. A quick shot of the drill sorted that, after a peek behind the panel to make sure everything else was in place for the mount.

After fitting the bolts loosely, I jacked up each side of the de Dion until the radius arms were nearly level – the car started to lift off the stands, so I called that “close enough”. I tightened the radius arms and A-frame fixings to the required torque and sat back with a complete rear suspension in place.

Now I have a quandary. Put it on it’s wheels, chock it and start the engine? Or bleed the brakes, do the interior stuff like fitting carpets and seats, and then start the engine? What to do?

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