Ignition Switch - broken lock cylinder [1972-S1]

(Marcello Giuseppe D'Ambrosio) #1

Hello, a month ago the key was not turning inside the lock cylinder of my car. Similar to when the steering is locked and you cannot turn the key. I tried to change the drivetrain from park to drive than back to park and the key still was not turning.

A friend of mine tried as well and he turned the key too much, and now the key turns with no resistance. I do not know what was the problem, but anyway, now is too late, because the cylinder is broken. I have to replace the lock cylinder but has been quite hard to find a used one for sale.

Do you guys know if the cylinder from another series should fit in my 1972 Series 1? Or if any other cylinder would fit? Had someone experienced the same situation? I live in NZ, and it has been hard to find parts around here, do you recommend any store that sells used parts?


(Carl Hutchins, Jr. ) #2


My Jaguar is a couple of generations younger, but, I do have a couple of ideas:

  1. There is no mechanical interlock in these cars between shift lever positions and turning the key.

The only relation to the ignition switch and the key is crank or no crank. An electrical inter lock.

  1. However, at times the key will not turn and a twist of the steering wheel will relieve the bind.

  2. If you have a full service locksmith nearby. Help might be found there. Remove the entire ignition switch and take it there. The key/tumbler part might be replaced with another.

  3. Decades ago, I broke the key in my IHC Scout II. In run position but, not running!! I made sure the transmission was I park. I jump wired the starter, carefully., Engine started. off to the lock smith. The apprentice assigned the task of removing the lock cylinder. done with a carbide hole saw. Not needed in a Jaguar.

The master took over and found a compatible cylinder and key. Fixed…


(Frank Andersen) #3

All ‘series’ lock cylinders are interchangeable, Marcello…

It’s standard ‘Yale’ configuration - and brute force will break the pins inside. Which are there to prevent the lock cylinder turning with an improper key, and which have a tendency to stick when old and unlubricated…

I assume that the key otherwise operates everything as it should?

xj6 85 Sov Europe (UK/NZ)

(Jochen Glöckner) #4


if you can turn the cylinder in the barrel now, you should be able to separate the the entire lock cylinder from the steering column and pull the cylinder itself (i.e. the turning part) out of the barrel. The broken pins will fall out. Take care of the minuscule springs though, as you need to retain these.

With some patience and I bet pretty much any other similar lock you will be able to restore the function of the original lock with the original key by undoing the pins from your donor lock in the same way and finding out in which order the standard sized pins are inserted to allow the key to pull in the pins. Don’t worry, you won’t have to try and err 99999 times - once open it is fairly obvious where the pins belong.

Certainly not a job for motorically handicapped ham-fists, but very doable and extremely satisfying!

One caveat though - my own experience is limited to door locks and everything written above based on the assumption that the locks will work similarly …

Good luck


75 XJ6L 4.2 auto (UK spec)

(tony) #5

have you got the shear-head screws out using a prick punch & hammer?

this is needed & allows a S1 barrel to be removed, I think it allows the steering lock shaft to be withdrawn…check the FSM

at that point, you can either repair the broken lock barrel, take it to a locksmith, or replace.
I do not know whether new are available…check Barratts…ring the Dealer

I have seen “universal” replacements installed on various vehicles.

Once you have the lock barrell out, you can at least drive the vehicle, by hotwiring it

I had a vehicle with amongst its many faults, was a busted ignition lock, with obvious hotwires…it got stolen, and broke down on the thief…who abandoned it in the middle of the road with the doors open, he would not have known you also had to usually jiggle the trans/NSS switch to get it started, door handles were all busted as well, worst design of door handle I ever seen on an auto

(Frank Andersen) #6

They do, Jochen…:slight_smile:

xj6 85 Sov Europe (UK/NZ)

(Carl Hutchins, Jr. ) #7


  1. Driving a hot wired car with a punched out ignition lock should interest the average cop!!!

  2. I did seek to fix my igniton switch. I guess I am one of the guys Jochen referred to. bits flew every where never to be found.

  3. On an other forum, I read that one should perform that task inside a clear plastic bag!
    Ugh, too late for me.

  4. I think mine was worn past redemption, anyway. I’ve a ti n loaded wit ignition switch bits… Why???

  5. Decades ago, a “locksmith” fixed a door lock for my son’s 40 Ford. Little left of the pins !!! Any durn key would unlock it… Or even a facsim ilie of one!!!


(Jochen Glöckner) #8

No Carl, I certainly didn’t have you in mind, but yes, I read that trick with the plastic bag as well, and yes, I’d endorse such practice having opened difficult objects several times over my messy work bench and once even over a big bucket full of fire wood … It took about ten times as long to recover the nut that fell into the bucket than to fix he widget it belonged to:-)

Good luck


75 XJ6L 4.2 auto (UK spec)

(tony) #9

talking to a gent today, he dropped the screw-on tip of a spark plug down into the cylinder, and as they are made from aluminium, a magnet could not be used, and he took the head off.

I have had bad thoughts of doing that myself, and always stuff an XJ motor timing chest with rags, to stop a fastener, or even spanner, bouncing down into it

(Carl Hutchins, Jr. ) #10

Spark plug nut in the bore:

Been there decades ago. Way back when, I bought a somewhat battered 40 Ford 1/2 ton pickup. cheap, as it lacked an engine and transmission.

I got an almost complete 53 Mercury V8. Because of the marvelous interchange of ford stuff, it was a fit. Gained CI’s via a 1/4" stroke.

It had issues!! Not concealed but disclosed. I found it on removing the heads. One bore OK, but the piston beat up pretty good. The culprit present ! Spark plug nut. Fixed and it ran like gang busters!!!

I’ve not seen a spark plug with a detachable nut for decades. Good thing, huh???


(tony) #11

I think most of them still have those aluminium bullet heads that can be unscrewed ?

(Frank Andersen) #12

That sure must have been unnecessary, Tony…??

xj6 85 Sov Europe (UK/NZ)

(Andrew Waugh) #13

When I was young(er) and foolish(er) I once helped a woman who’s Impala wouldn’t start. It was about -20C, She had stalled right in front of our house (I was shovelling the driveway).

I can’t remember what was wrong, but it was diagnosed and fixed pretty quickly. As I was putting it back together I slipped and dropped the wing nut from the air filter top into the carb. Not being one to do anything by half, I also hit the throttle linkage (while still trying not to fall over) which allowed the wing nut to fall past the butterfly down into the intake manifold.

I finally managed to get it out with a small magnet on a bit of fishing line, but it was a long, cold struggle (about an hour iirc).

Since then, whenever I take stuff of the top of a top draft carb, I walk away from the car and store the bits at a safe distance, and return with a rag to cover the top of the carbs.

(tony) #14

clumsy to be sure, it was a WW2 Jeep, so the bullets may have been needed to attach the wires to the plugs?.

have noticed the bullets are sometimes loose, and undone at least one NGK myself, which is why I know they are still made like that, for whatever reason

personally would have got my vacuum cleaner, and taped a long flexible tube, insert into plughole, probably happened before the days of cheap endoscopes

wouldnt be hard to pull a WW2 Jeep head

(Carl Hutchins, Jr. ) #15

At least the search field was limited to the bucket and not the entire shop and beyond !!!


(Jochen Glöckner) #16

Right. Damage was limited, but an hour of precious lifetime lost by simple lack of anticipation … if that happens to you at age 16, well, you should learn your lessons. If it happens aged 46 you become skeptical about your learning curve …

Good luck


75 XJ6L 4.2 auto (UK spec)