I have the tunnel cover up, whats the best strategy for disconnecting the handbrake cable
IME the best strategy is to go under at the back, slacken the tensioner then just push the cable back from under there into the tunnel, to disengage from the diff bracket. No need to lift the tunnel.
The simplest way is to remove the split pin and clevis pin (#2 here):
Remember to cross the cable inner over when reassembling.
Thanks both, ended up pulling the pin and removing the entire assembly. I found the cable had a kink and damage to the plastic sheath. To prevent an potential balance issue, I've opted to replace the cable. As result the project has been delayed.
Old diff is out, drained and the back plate removed. I've then wiped the diff internals down for inspection, though I openly admit I'm not sure what I'm looking for in terms of faults. It certainly looks ok, i.e. nothing loose or broken. The oil had an interesting finish to it, certainly some traces of metal, but nothing significant. I've run a magnetic pick up tool through the oil and nothing notable. I also put a magnetic parts tray under the drain pan, again nothing amazing. I do admit I'm not really sure how the oil should really look.
I'll upload a slide deck to Youtube rather than spam images to here. Would love to hear opinions.
It wasn't all good news though. Removal of the shafts etc all went well, and once I committed to disassembling the handbrake assembly (thanks btw) I got the diff out with ease. Unfortunately I found a nasty kink in the handbrake cable and some heavy marring and compression on the plastic outer. Not ideal, so I've very reluctantly opted to stop, and source a replace cable. Very disappointing as I'd spent a long time preparing for this weekend, aim being to get the new diff in and the car built.
I'm not sure why the damage occurred to the handbrake cable, I've never had any issues with it during use, and it was balanced during its Manx IVA. Bit of a head scratcher.
Youtube based slides deck
Interesting you mention a kink in the handbrake cable. I have a imbalance problem with the drivers side being stronger. I removed the tunnel cover and found a nasty looking kink in the inner cable close to the pulley area. I plan to replace the cable over winter but wondered how it came about - to avoid the same thing happening to the new one. Does your cable cross over just after the pulley (to stop it scraping on each side of the chassis)?
Hey, Yep it crosses over too. Your location sounds very similar too, sort of helpful to know it's not something isolated to my car and possibly something daft that I've done.
CC parcel arrived this week. New handbrake cable and the 5 speed gearbox spacer. Not sure if I will be inclined to work on the 420R this weekend. I did tell myself to take my time over the process and enjoy it. It's pretty cool too, reminds me of my original build.