Tuesday, October 30, 2018

Rear Hub Removal

With front hubs and brakes removed, I turned my attention to the rears. From the outset, this looks very similar to the front brakes, so should be easy. 

Rear corner assembly – before starting

Rear disc brake removal

The removal of the rear brake calipers and discs is almost identical to the front corners. Therefore only a summary of the steps is given below.

To remove the calipers undo the two allen headed bolts located at the back of the disc, which are contained within separate rubber tubes. With the calipers removed, the brake pads can easily be removed, or watch them fall out. The caliper carrier is fastened to the hub by two 15 mm bolts. The difference with the rear is that unlike the front these bolts have been wire locked together. Not sure why only the rears get this treatment, especially as the front brakes are more powerful. Now that the brake assembly is removed, the rear corner looks like this.

Image from the back of the IRS with the caliper carrier removed

Rear disc with the disc brake assembly removed

Not unsurprisingly the rear brake calipers are considerably smaller in size than the front brakes. They are however equally rusty and dirty, so will need a good clean. 

Both rear brake calipers and carriers
With the caliper carrier removed the disc can be removed by removing the grub screw. The grub screw on the near side was very difficult to remove, as the screwdriver head kept slipping. I did manage to get them out before totally stripping the head, but only just. These will certainly be replaced!

With the rear brake pads and discs removed, it is clear these are not in the same good condition as the front. As the images below show, there is significantly less meat on the pads and the discs have a very pronounced lip. Certainly, these will need to be replaced when building up the rear suspension on the AK chassis.

Rear brake disc and pad. Very little meat left

Notice the rim on the rear brake disc


Rear handbrake pads

Now that the rotors have been removed, I was slightly shocked to see that the handbrake is operated by internal drum brakes. Who would have thought that even in the 1990’s drum brakes were still used on Jaguars?

To remove the drum brakes first ensure that the self-adjuster at the top of the hub is fully screwed in. This reduces the tension placed on the pads making them 'easier' to remove. Then there are two NO. no. 5 allen headed clips which are held in place by a spring. These are removed by depressing the clip head and twisting free. With these removed and with a little more wiggling, the retaining springs holding the pads together can be unclipped. After removing one or both springs, the pads fall away from the hub. The last step is to detach the brake cable from the ‘fixing’ plate, by sliding out the middle pin. To avoid losing this small pin, I taped it back into the fixing bracket.

In hindsight, having removed the hub before tackling these drum brakes might have been easier, if possible...

Hub and IRS Removal

Now that all the brakes have been removed, the strip down of the hub and IRS really begins. For reference, I have referred to the following exploded diagram of the rear corner assembly which I found online.

To remove the hub there is a 27 mm nut which fastens the half shaft spline to the hub. These require some serious torque to remove. The near side nut required a week of regular WD40 spraying and then additional weight to resist the lifting of the differential when using the full extent of my up-cycled breaker bar.

With this nut loosened, but not fully removed, a good set of pullers is required to separate the half shaft from the IRS. Leaving the nut on ensures the whole assembly cannot fly off. This is another tip I remembered from Ed China.

Dirty rear hub removed from hub carrier
Luckily, all the races have stayed within the hub, which saved on the mess created. The only part which did fall off was the cogged wheel, which I believe is used by the ABS sensor to detect a differential wheel speed. This seems to be a press fit against the outside surface of the hub shaft and helps secure the hub within the IRS.

With the hub removed, I foolishly undid the IRS fulcrum shaft. This nut came loose relatively easily using the large breaker bar and the shaft itself came out with some persuasion. With the IRS away from the swing arm, the handbrake cable can now be removed. This is held in place by a semi-round plastic clip which sits just behind the hole for the handbrake cable. By rotating this clip, so its cut out is facing upwards you can gently pull this clip off.  Now the cable should just pull out from the IRS.

Inside view of the rear hub carrier
I then planned to remove the splash shield. This is fastened to the IRS with 4 no. 8 Allen headed bolts. These are obscured when the hub was fitted. However, there is a small cut out in the hub, which I assume is there to gain access to these bolts, but it is far too small for my sockets. I found the best way to remove them was to put the IRS back onto the lower swing arm, which prevented any rotational movement as I used my smaller breaker bar with an Allen key slotted inside to loosen them. With these four bolts removed the shield falls off from the IRS.

Removal of the rear splash shield
Now the shield is off, I can again remove the IRS from the swing arm. Having separated the major components from the rear swing arm, my work on this corner is done for now.

The layout of the disassembled rear corner
I will tackle the further breakdown of the half shafts and the hub carrier later.