Diff & Rear Suspension

First job on the rear axle assembly is to get the handbrake installed (!)... This is because it is easier to route the handbrake cables without the diff in the way. The handbrake went in without any problems - I had to wind out the adjuster quite a long way to be able to get the clevis pin to mate up with the handbrake assembly, but otherwise no difficulty. I have wired up the brake microswitch to the connector on the harness, although there is no mention of this in the manual - hope it works!

The next thing to do is insert the propshaft into the transmission tunnel - do it NOW, before the diff goes in! It is not possible to install the propshaft after the diff is fitted.

Diff installation is next. I put the diff on a wooden block on top of the trolley jack and gently raised it into place, this seemed to work quite well (it was too heavy to lift into place manually). The bottom bolts go in quite easily, and it is relatively straightforward to add shims to get the diff centralised left-to-right across the car. The top bolt was a bit more tricky, I had to thump it in with a soft hammer, which made adding shims quite tough! I used sellotape in a ring around the washers to keep them together whilst inserting them between diff & metalised bush.

Having torqued the top bolt, I removed the lower bolts one side at a time and put Loctite on each before re-inserting and torquing up. Final measurement of the diff centrality left-to-right is within 0.5mm.

Next job according to the Guide is installation of brake pipes onto the De Dion tube, but before this I decided to add some rustproofing to the inside of the tube. I squirted Waxoyl as far as I could, from each end, to try and stop the tube rusting if there is any moisture ingress.

Next I put the tube on my workbench and lightly bolted the aluminium hub carriers, caliper brackets and brake calipers to each end. I installed the 3-way brake union onto the tube (the nut was very difficult to tighten, it was getting really hot and I thought I was stripping the thread - but I was definitely using the right size according to the Guide, and it feels OK now). The brake pipes fitted OK but both left & right pipes needed to have the final 10cm bent into a semi-circle in order to locate properly into the brake calipers. I clamped each pipe into a bench vice (with soft jaws!) and hand-bent the pipes using my 41mm hub socket as a former...

Next the De Dion tube is inserted into the chassis, behind the diff. I protected the chassis rails with foam wrap in order to prevent scratches. The rear shocks and radius arms go in next, and these are bolted to the De Dion tube. I'm not going to torque up these bolts until I can put the weight of the car onto the wheels/springs, to make sure the rubber suspension bushes are not twisted under normal loads.

The radius arms stop the top of the De Dion tube from rotating, and the bottom of the tube is held in place by an "A-frame" bracket. The apex of the A is bolted to a central rubber bush on the bottom of the De Dion tube, and the two arms of the A to the suspension bushes in the front of the wheel arch. Installation was straightforward except that the central bush can only be tightened with a very thin socket set (the nut & bolt are recessed into a metal sleeve). Also there are badly-fitting nylon washers either side of the bush, which do not fill me with confidence....

My kit did not include a rear anti-roll bar, so the next job is to build up the remainder of the hub components onto the De Dion tube ends. This starts with inserting the drive shafts into the diff, then locating the aluminium "ears" and the main hub carrier bearing over the ends of the shaft & De Dion tube. These are then bolted in with loctite and torqued up.

After this, the brake discs can be located over the driveshaft ends and the big locknut screwed on (note that the shaft on the left side of the car has a counter-clockwise thread). The nuts are supposed to be done up to 270nm, but I'm just taking up the slack for now until I can lock the wheels properly.

The speed sensor is screwed on to a small bracket on the right-hand-side hub, and adjusted to be 1mm away from the serrated ring on the driveshaft.

Finally the brake calipers and pads can be installed onto a carrier assembly that bolts onto the top of the aluminum hub ears. The brake pipes can now be screwed into the caliper assembly, and the handbrake cables connected.

Ready to roll!

Adjusting the handbrake tension was extremely difficult. The adjuster plastic nut is hard up between the diff and the chassis, and I found it almost impossible to tweak from below. It's much easier from above, but after the interior trim is installed this won't be possible... Hope I don't have to adjust it any more!

Last but not least, I filled the diff with the EP90 oil. I did this from above, using a funnel on a 2ft pipe, having removed the boot floor. Whilst I was there I also painted the wooden bit of the floor with preservative.

Interior is next up....