Boot in locked position doesn't operate

[Patfallon]

Hi, I've looked but can't find this problem on the forum. Apologies if I've missed it and am repeating here. My car (1988 convertible) has been left standing for some time due to issues beyond my control. This has resulted in a dead battery; no instrument or ignition lights.

Central locking is not working but the key opens the drivers and passenger doors individually. However the main issue is that the key will not turn in either direction in the boot lock which is currently in the horizontal position.

I thought to power things up utilising the +post drivers side, under the bonnet, using a NOCO boost GBX45 but this did nothing. I'm wondering if it didn't work because the battery is too far gone.

My next plan will be to use jump leads on the same +post but I don't have time this weekend as I will be back abroad working for another month.
Any comment on the futility or otherwise of my next course of action would be appreciated. Obviously I don't want to drill into the boot but, if I have to, I would need some instruction. Thanks

[mike020150]

It's a while since I ran an XJ-S but I can't recall anything particularly unusual about the way the boot/central locking mechanism works. Assuming the key is the correct one (have you tried others?), it's possible a lack of use can allow a build-up of dirt and corrosion causing stickiness or seizure of the lock. Typically, a good soaking with a freeing agent (e.g. WD40) is enough, along with some patient gentle working of the key in the lock, to overcome the problem. Mike.

[JimMann]

As far as I can remember, the electrical switch for the boot release on the XJS is a large click switch to the right of the centreline, under the boot plinth. Turning the manual key also activates the boot release solenoid - I don't know if it actually moves the lock mechanism though.

If you can access under the bonnet and attach a power pack or another battery to a +ve and -ve point in the engine bay, you should be able to power the car. Don't try any power up activities other than clicking the central locking to unlock the overall car. You should then be able click the boot lid switch and allow it to open.

Jim Mann

[PaulGover]

I removed my battery for charging and locked, and unlocked, using the key. I believe both operations can always be performed without electrical power. The key mechanism has 3 positions, AFAIR if you turn it all the way anticlockwise it locks in such a way that it won't unlock electrically; if you turn it half way, it locks and unlocks electrically; if turned fully clockwise it's unlocked.

If the boot won't unlock, my experience from the door lock mechanisms suggest it's rust or crud stopping the linkage from moving. The other possibility is one of the cranks jumping out of one of the cranks - they're usually locked in place with spring clips integral to the nylon bushes in the crank, but if the mechanism is reluctant to move, trying to force it might push the lever out of the clip and crank.

I recall reading, perhaps in these forums, that there's a place in the boot lid, behind the number plate, where you drill to get access to the links with a pair of pliers to try manually moving them.

If the issue is that the lock barrel won't turn, try spraying penetrating oil anywhere that looks useful, and check (as before) you're not using the valet key. However, it does move levers at the back, so if they're seized, see the above...

[poprivet]

I agree with Paul with the seized lock barrel. With central locking, the boot rarely gets used with a key. It could have been seized for a long time without realising.

Use something like Plus gas rather then WD40, gently work it in with the key and maybe let it sit for a while.

[JimMann]

Folks, it might sound old fashioned, but one should never introduce liquid lubricant / penetrating oil into a barrel lock, and certainly never WD40 - that's a guaranteed future problem. Only dry lubricant such as graphite from a scraped pencil if nothing else is readily available should be introduced into the barrel.

Scrape a graphite pencil over the key tangs and gently push it into the lock barrel. Repeat as necessary to get the key fully into the barrel without trying to rotate the key in the barrel. Then continue using graphite from a scaped pencil on the key tangs whilst gently working the key in a rotational movement. It requires patience, but it will eventually work unless the barrel tangs have disengaged from their retaining clips, then it is on to the drastic action as mentioned by Paul.

Jim Mann

[Patfallon]

Thank you for your responses and suggestions. I’m 100% happy that the problem has nothing to do with rust or build up of dirt. The boot lock has been regularly exercised and always worked smoothly.
No issue in using the same key for nearly 20 years either.
My thinking is to take a battery and connect to the under-bonnet post when I get home. I had thought the boost pack I referred to in my post would provide power, but maybe not.

Thanks again. I will post the result of my actions when I get home and have tried the battery route.

[ptjs1]

Patfallon,

I can't speak for a pre-facelift car (although would be very surprised if it's different) but on the later facelift cars, the movement of the boot key and the operating of the lever and lock opening, is not all dependent on any battery power. I have one such car with me at the moment with the battery disconnected, and manual locking and unlocking of the boot is a daily affair.

The boot lock barrel is a manual affair. If you can't turn the key, there is a barrel issue. Battery power will not help you imho.

You may already have done this, but just try gentle wiggling up and down whilst applying careful clockwise or anti-clockwise pressure on the key. Even also slightly moving the key in or out may help.

As I said, earlier cars may be different, but I doubt it.

Good luck

Paul

[Patfallon]

I’m now back in the UK and have had anther go. I bought a new battery and after a bit of fiddling with the leads on the underbonnet post and an earth I finally heard the click that said everything was back to normal. It took a few applications but the lock started working manually again. Thanks to everyone.