Saturday, August 4, 2018

Front Hub Strip Down

The first part to strip down from the heap of Jaguar parts, will be the removal of the front disc brakes and hubs. This is a very exciting first step echoed by the immortal phrase ‘How hard can this be?’. 

Brake discs and Calipers 

From an initial inspection, the front brakes look to be in reasonable condition with plenty of ‘meat’ left on the brake pads and the discs don’t appear to have much of a lip at the rim. These might be a candidate for saving… will have a closer look later. 

Image of front disc and pad after removal 

The front brakes are removed in two stages. First, there are two no. 7 Allen (Hex) key headed screws contained within a rubber tube behind each caliper. To access these, pop off the plastic cover from the rubber tube with a screwdriver and then with the Allen wrench these bolts are relatively easy to remove. By then pulling the caliper towards you and pressing the inboard brake pad to the rotor, you can push the brake piston back into its housing creating enough space to remove the caliper from the rotor. Of course, it’s obvious (with hindsight), that because the brake lines have been cut, when you squeeze the brake piston, brake fluid will come out of the brake line. I only realized this when I spotted an oil patch on the floor, luckily, I had put some newspaper down. 


Image of removed calipers 

With the calipers removed, the next step is to wiggle out the brake pads away from the caliper carrier. This leaves the rotors exposed with the caliper carriers as shown below. 

Front hub minus the brake pads and caliper

The next step is to remove the caliper carriers, which are each fastened by two 17 mm bolts through to the front upright (threaded holes). These bolts required a few goes with WD40 and a breaker bar. As a home DIYer, my choice of breaker bar went through several iterations. 

I have a breaker bar which came in my Halfords socket set, but it is not the longest at 180 mm and so struggles to shift some of these bolts. Definitely room for improvement in regards to length, in order to gain greater torque to remove the more stubborn nuts/bolts. A quick look online found a selection of breaker bars with a maximum length of 700 mm. Whilst I considered buying one, I thought I would try making my own, at least for the short term. I began with a spare piece of wood found in my garage and taped it to my breaker bar. This did work, but with limited results. I then spotted my old bench-press bar (2.2 m in length), which turns out to be a hollow tube that my breaker bar fits inside. Perfect! With my up-cycled breaker bar, removing these few bolts was straightforward. What was it Archimedes said? "With a lever, I will move the whole world" 

Original wooden breaker bar 


Comparison of an up-cycled breaker bar with the wooden breaker bar 


Up-cycled breaker bar being used to remove caliper carrier bolts 

The last part of the brake disassembly is to remove the rotor. This is simply by the removal of the small 'grub' screw found on the front of the disc. With this screw removed, the rotor then slides past the wheel studs. 

Front corner with the brake rotor removed 

To avoid losing the wheel nuts and the small grub screw I put them back on the front subframe. 

Hub disassembly 

After removing all the front brake parts, the hub is now exposed and is the next culprit to be removed. To guide me through this process I found an illustrative schematic of how this component is put together from the internet, shown below. 

Schematic of the front hub from http://www.justjagsuk.com 

So the first step is to use a flat head screwdriver to prise off the central hub cover. This is the dented, doomed part in the previous photo above. 

These next steps get very messy, due to the packing grease in the hub. With the doomed cover off there is a 15/16 nut, secured with a castellated cover and a split pin. The split pin unfolds easily with needle nose pliers and slides out. The castellated cover then slides off and lastly the nut below un-screws relatively easily. 

Front hub split pin and nut – Image from AK manual 

Now the hub assembly slides off, in my case, with very little force. As it comes off, a range of spacers and races will probably fall to the floor. Whilst I might not use them again, I will keep them safe so if I do replace them I know what I am looking for. 

Front hub removed
Behind the hub and its bearings, there is even more grease and a few more bearings within the cupped shaped housing. This casing is fastened to the main upright by three small TORX no.T30 headed bolts. With the vast amount of grease that packed this area, there is no need for WD40. 

Even after removing these bolts the housing and back plate did not come off easily. It was held in place with an oil seal, which as its name should suggest, is a tight fit and holds the housing in place. To remove the housing and backplate, I found it helpful to place a medium pry bar down between the hub housing and the plate and gently wiggle the housing off. As the housing comes off it brings with it the oil seal. This then allows the back plate to fall off the front corner exposing the front upright with its wishbones and ball joints. 

Front upright after brake and hub removal 

Having tackled the front breaks and hubs, next onto the rear to do the same.