Rear Axle Reassembly - Part 7 - Pig Pen, this here's Rubber Duck...

Before the rear hubs can be reinstalled into the carriers the brake backplates, which hold the handbrake mechanism in place, need to be fixed to the hub carriers.

In my view, there is a distinct flaw in the Jaguar design for this set-up.  The hub carriers are aluminium and the brake backplates are steel.  Fixing the two dissimilar metals together results in a chemical reaction, known as galvanic corrosion.  This accelerates the breakdown of the natural coating of the aluminium and produces aluminium oxide (remember all that white crusty crud under the backplates when the hubs were stripped down).

This process is exacerbated by moisture and salt (like er...road salt) and so to ensure that the conditions for this galvanic corrosion are fully optimised, the Jaguar engineers decided to leave the aluminium mating face of the hub in a rough cast form to really allow the ingress of water, dirt and salt to take place, and then to ensure that it remains trapped in place to do its evil deed. 

A haven for dirt, debris and road crud!

A number of solutions have been proposed on the various build blogs that I have perused; including just bolting it all back together, a liberal application of copper grease, or the use of the dreaded RTV silicone sealant.

I decided to try an alternative solution and go with a rubber gasket.  This should keep the two metal components separated to reduce the opportunity for galvanic corrosion and also, hopefully, keep water and crud out of various nooks and crannies resulting from the rough cast face of the aluminium hub.

I made up an initial paper template. The centre hole was sized by placing the backplate on a sheet of paper and simply running a pencil around the edge of the hole.  This was cut out using a sharp knife and placed onto the hub.  Using a suitably greasy finger, I rubbed over the paper to trace the shape of the edge of the hub and the screw mounting holes.  The template was then completed by trimming the outer edge and screw holes.

Why you shouldn't wash your hands.....

Final template

I then stuck the paper template down onto a sheet of 1mm thick rubber sheet (purchased from that well-known internet auction site).  I used a scalpel to cut around the edges of the template and create the rubber gasket.  The template was stuck down a second time and the process was repeated to create a second gasket.

Template stuck down onto rubber sheet...

...and trimmed to create gasket.

A perfect fit!

Now I have sorted this issue I can press on with reassembly...