Rear Axle Reassembly - Part 8 - Tubeway Army

 With my rubber gaskets sorted, it was time to get the brake back plates bolted onto the hub carriers. 

Although as I was mocking up the parts for reassembly, I noticed that the brake back plates are not particularly stiff where the handbrake cable passes through them.  The AK handbrake has come in for a bit of stick on many forums for its rather marginal performance.  My thought was that if the back plate flexes from the applied tension in the handbrake cable then this could be a factor in reducing the efficiency of the system.

The original Jaguar setup had a small spigot tube bolted to the back of the backing plate, through which the handbrake cable passed, and then a plastic clip between this tube and the hub carrier to hold the handbrake cable in place.  It is conceivable that this arrangement could offer some sort of limited bracing between the hub and the back plate (although that's possibly wishful thinking).  In any case, this option was not available to me as my original spigot tubes are now a fine lacework of rust and replacements are not available.

A small spot of tin worm...

My solution was to make a couple of spacer tubes to sit between the hub carrier and the backing plate that would serve to brace the backing plate and reduce any flex during application of the handbrake and also protect the exposed part of the handbrake cable from the elements.

This was an opportunity to press my "new" lathe into action.  This is a story in itself, but the short version is I foolishly put a bid on an old Myford ML7 lathe on the well-known auction site thinking that I would be outbid...and ended up winning the bid.  To be fair, it was in pretty good condition and came with lots of tooling, so it was a very reasonable (if unexpected) purchase.

I made some measurements and knocked up a quick CAD sketch of my intended solution, being a tube with a flange at each end to bear onto the hub carrier at one end and the handbrake mounting block at the other, with a small stub at each end to locate tube in position and a hole large enough to allow the clevis on the end of the handbrake cable to pass through.

Original Design Sketch

The spacers were machined from 25mm aluminium bar stock, faced and turned to size, a 12mm hole drilled down the middle, and finished off with a boring bar (twist drill bits do not produce a true circular hole).  I made the stubs at each end slightly longer than my original sketch (to facilitate machining) and I also machined a groove in the hub carrier end to allow the use of an O-ring to fully seal the tube to the hub carrier.

Aluminium bar after initial facing and turning - with tail support

Machined down for stub at one end

Location of flanges marked out

Spacer waisted out between flanges and larger stub formed

Drilling 12mm dia hole after 6mm pilot 

Completed Spacer Tube

Spacer in place between hub carrier and back plate

And to finish off this completely over-engineered component that will probably never be seen by human eyes again, I powder-coated it in the obligatory metallic red that I have chosen for all such parts on the car!

Further unnecessary bling!

Now I think the hubs can finally be fully reassembled.