Boot Lock Failure - Removal and Repair
 

The following instructions on the repair of the boot lid locking mechanism is the work of Michaela/MikkiJayne/D2 Doctor and is a single post extract from one of her threads. I've posted it as a separate thread to make it easier to find.

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Also fixed the boot lock since it was seized completely solid

Removed via the door for for the light cluster

http://forum.a8parts.co.uk/attachmen...1&d=1524342355

Disassembled the main body

http://forum.a8parts.co.uk/attachmen...1&d=1524342355

http://forum.a8parts.co.uk/attachmen...1&d=1524342355

http://forum.a8parts.co.uk/attachmen...1&d=1524342355

The lock barrel was completely seized in the housing. Lots of WD40 and wiggling and it finally came free.

http://forum.a8parts.co.uk/attachmen...1&d=1524342355

Crusty!

http://forum.a8parts.co.uk/attachmen...1&d=1524342355

Started removing the tumblers

http://forum.a8parts.co.uk/attachmen...1&d=1524342355

http://forum.a8parts.co.uk/attachmen...1&d=1524342355

All disassembled. It took about half an hour cleaning schmutz out of the barrel with an assortment of pokey tools, degreaser and compressed air before the little door would close again!

http://forum.a8parts.co.uk/attachmen...1&d=1524342355

Cleaned all the tumblers up

http://forum.a8parts.co.uk/attachmen...1&d=1524342355

Reassembled prior to re-greasing

http://forum.a8parts.co.uk/attachmen...1&d=1524342397

Going back together

http://forum.a8parts.co.uk/attachmen...1&d=1524342397

http://forum.a8parts.co.uk/attachmen...1&d=1524342397

http://forum.a8parts.co.uk/attachmen...1&d=1524342397

You can see the cam which operates the central locking here via these two microswitches

http://forum.a8parts.co.uk/attachmen...1&d=1524342397

All back together and ready to put back in

http://forum.a8parts.co.uk/attachmen...1&d=1524342397

Thanks Sean +++

Refreshing my memory on how this goes together, I think the key just spinning may be caused by the tab on the end of the lock barrel not being engaged properly in the rest of the mechanism. Given that this whole thing is mostly lightweight pot-metal it could be that one or more pieces are actually broken, but if that is the case then either the barrel, or the individual tumblers could be swapped in to a used lock mechanism to resolve the problem while keeping the same key.

If anyone wants to remove a spinning lock and send it down for diagnosis / repair then let me know :)

I've been having a look at David's lock over the weekend. Everything seemed in good order and nicely greased, but the barrel was stuck fast in the surround. After sitting overnight in WD40 I managed to get it apart and discovered that it was just corrosion on the first few mm of the barrel holding it place.

http://forum.a8parts.co.uk/attachmen...1&d=1613947807

After cleaning, it was clear why - the rubber seal was perished and disintegrated so moisture could get in.

http://forum.a8parts.co.uk/attachmen...1&d=1613947807

The seal is a flat-ish moulded thing which is not available as a spare part. The thought occurred that an o-ring might work to replace it, and the oil cooler pipe o-ring appears to be just the right size

http://forum.a8parts.co.uk/attachmen...1&d=1613947807

It actually goes together quite well, but its a little stiff to turn so it might need a smaller o-ring.

http://forum.a8parts.co.uk/attachmen...1&d=1613947807

Or, I might see if I can print a polyurethane replacement for the original seal.

Mine doesn’t have a seal there at all, and the barrel was corroded at the top end like David’s. I’ve got a load of different sized O-rings, so I’ll pop one in when I fit the last tumbler. Good job you pointed that out, otherwise I expect mine would have corroded again in no time!

I'm about to try printing one. If it works, I'll post you one with the tiny spring which will be on its way this afternoon :)

The printed part is perfect for the job +++ will post a pic later

You’re a star! Thanks Michaela

Printed seal in place:

http://forum.a8parts.co.uk/attachmen...1&d=1614072544

Thanks MJ, +++
Neat job .... and now youve shamed me with the state of the key (its lost the audi rings and generally looks old and battered like its owner), im going to have to get a new key!!

The solution is cheap as chips for missing rings.... http://forum.a8parts.co.uk/showthread.php?t=15821

I did think about that but its a bit past just putting some shiny rings on it. And besides, ive always wanted a Bentley key so Im justifying it to myself :ROFL:

Michaela's spare teeny weeny tumbler spring and 3D printed seal arrived today, so my boot lock is now back in place and working fine! :)

Just discovered that my boot lock isn't working either. Have removed it from the car, removed the black circlip at the end and the black plastic piece it's securing, but I'm lost as to how it comes apart. What's the correct sequence?

From the pictures, and using some logic, you do have the (correct) key blade inserted? ;)

Loosen the crimped ring from around the front bezel then lever the bezel off the housing and the assembly will split in to two parts with the spring between them.

You will need the key inserted to get the barrel out of the housing.

Since posting, I had another look at the photos and deemed it necessary to remove that crimp ring. However, it seems I'm not 'levering' enough. At least I was on the right track.

The black plastic snaps in to grooves on the rear metal housing. It can help to warm it up a little, then lever it off with a screwdriver +++

Too right. +++ Plastic was as hard as the metal. Finally got it stripped, cleaned and reassembled and could have done the job a lot quicker if I'd had a pair of circlip pliers to hand.

EDIT: Forgot to mention the problem with mine. The lock barrel was seized in the housing, just like the one MJ was working on. Of the eight tumblers, only two were stuck in position, but what surprised me was their colour, as I was expecting them to be black like in the photos in the thread. Turns out only two were completely black and the rest had about 10-15% black.