Propshaft and differential install

I got some help with this one. Craig came over for a morning to check out progress and help with lifting the diff into place. The diff is a heavy lump of metal, made more awkward by being an odd shape, having a carrier frame around it, and needing to be positioned precisely.

First though, we tackled the propshaft. It was more awkward than I was expecting to get the prop into the tunnel, but with a bit of fiddling and some careful positioning, it slotted into place.

Propshaft in position

Propshaft in position

Those cables hanging down around the prop in the photo above are either side of the handbrake cable, hooked through the pulley of the handbrake but not yet positioned properly.

Next was the diff. First a fill with oil provided by Caterham – in the boxes comes 1L of oil for the diff, and the instruction is to fill it until it comes out of the filler hole. The diff takes 1.1L, so a run out to Halfords for another litre, 0.9L of which will sit on a shelf in the garage for a long time. Annoying.

Diff full of oil

Diff full of oil

I had the rear of the car on the highest setting of the axle stands for easier access underneath. As a result, a quick check with the jack under the diff showed that we could not lift it high enough, and even with the jack raised on some planks of wood, getting the right angle to get the top bolt in proved impossible.

We switched to the engine crane and lifted the diff into position through the boot with the wooden base removed. We got the lower bolts in first, and then pivoted on these to get the top bolt in. Lots of copper grease and a few good thumps with the rubber mallet from Craig saw the massive top bolt driven home. Thanks for the help, Craig!

Sorted - now to centre it

The diff is in!

One tricky thing to manage while lifting the diff is the run of the handbrake cable. The cable outer (the stainless covering you can see in the photos) is too thick to pass through the mounts on the diff frame, so this needs to be done with the diff close to installed. It’s fiddly, but with some planning ahead, manageable.

With the bolts in place and lightly tightened, I then measured from the frame of the diff to the outer edge of the ARB mount. I played about with the washers to get it centralised within 1mm either side – I used 2 on the left and 1 on the right but it wasn’t that far out with 1 and 1. A quick run with the torque wrench and the tippex pen and the diff is all installed.

On to connecting the propshaft to the diff, and this is simple but I still managed to get it wrong. Four bolts, tightened to 60Nm, but one snag: the grease nipple for the universal joint protrudes far enough to make it awkward to tighten one of the bolts. Thanks to fellow builder Simon, though, for pointing out that it just screws out. Popping that out, tightening the bolts and suddenly the front end of the car is connected to the back. Well, at least for an evening. The next morning I realised I’d copper greased the bolts in the propshaft. The next day I had to remove them one by one, clean out the threads, and Loctite them before replacing and re-tightening.

The next step for the diff was to lever out those covers where the driveshafts will go, but that would come later. First I needed to build the deDion, ears and callipers and fit some brake pipes.

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