Good morning everyone.
My car is a USA spec. '90 Majestic w/85k miles.

I've been having a problem with key turning the ignition lock to start the car.
IF I get the key just right it will turn but the process is a real PIA.
The green valet key works just fine, the black key works ok in the door locks.
Any thoughts on the problem being the lock cylinder or a worn key?

Thank you,
Roger

 

From your description, I think my eye would be on the black key. If the ignition cylinder works well at all then I would think it is good. I guess I would be trying to compare the 2 keys- or maybe a 3rd key if you're lucky and have one. I might also get a flashlight and see if maybe theres something stuck in the lock cylinder causing the upset. Good luck.

 

+1 on the black key. Can you detect any differences in the keys that might indicate that the black key is worn? I can't recall if the '90 keys are of the Ford Tibbe design, but I believe a good locksmith should be able to use both the green key and black key to make new copies that will work the glovebox and trunk as well as the doors and ignition.

 

Hi Don, thank you for the advice.

The article you wrote a while back was a good start for me.
I disassembled the entire ignition lock barrel and the following is what I found:

The XJ40 lock cylinder contains the Jaguar 8 discs (Ford is 6).
The lock cylinder is a separate cylinder within the outer barrel. It is retained in the barrel by a single snap ring installed in a specific orientation. The cylinder is slotted with a roll pin installed in the slot.

This roll pin is then "caught" in a groove machined in the bore of the outer barrel - caught between the slot and the groove - preventing the lock cylinder from rotating.

The Tibbe discs inside the lock cylinder when rotated by the ignition key all line up, opening up a slot in the top of the discs and permitting the roll pin to drop down out of the groove in the outer barrel thus allowing the lock cylinder to rotate, turn the ignition switch; which is keyed to the back of the "ignition lock/switch assembly" and start the car.

This all looks to be very complicated, but the reality of the design and operation is very simple.

I am fairly convinced that my problem is caused by wear to some of the discs in the lock cylinder. Discs 5 and 6 are not consistently rotating far enough to allow that roll pin to drop down all of the way out of the groove. It rolls out of the groove partially and then gets hung up between the lock cylinder and outer barrel preventing the key from turning and giving me major heartburn.

I have a new ignition switch, a new JLM2145 on order and when all is reinstalled I'll try to take the old lock cylinder apart and try to repair it.

I'm going to try to post some pics.

 

Roger,

We'll anxiously await your photos!

I once swapped the discs from our original driver's door handle lock to the lock of a replacement salvaged handle, so I'm familiar with the parts you are describing. Your analysis is excellent, so once you couple your descriptions with photos it will be a great resource for the rest of us.

The detail that still gives me pause is that the green key seems to work fine. Shouldn't that indicate that the problem is with the black key rather than any of the lock discs?

Have you compared the flats on the keys that correspond with the 5 and 6 discs to see if the black key's flats show signs of wear?

How To Read Jaguar Tibbe 8 Cut Key Codes

Please keep us informed!

Cheers,

Don

 

Hi Don. The green key is equally ineffective in turning that lock and both keys don't look to be worn. The thing that "bugs" me is that my car isn't high mileage and I'm at a loss to understand how this lock can be "worn out". Is it originally defective from the factory...?I'm going to to get some picture posted.

 

This is the entire ignition lock assembly from my '90 Majestic. The ignition switch is on the left, lock barrel on the right. The part at the bottom is the spring loaded ignition switch key. The round hole in the cast housing is for the lock barrel release button in view on tne barrel. The part number cast into the lock mount is CBC9128.





The lock barrel dis-assembled. The lock cylinder is in the center of the picture The slot in the top of the case is clearly in view with the roll pin below the cylinder snap ring





My black in the lock cylinder with the roll pin dropped down into the cylinder slot. Discs 5 and 6 don't consistently rotate enough to allow the pin to drop down out of the groove in the lock barrel.





A close up of the lock cylinder.





I still have to drive the car and this pic is of how I've had to adapt, innovate and overcome the lack of the ignition lock to do so. The upper bracket is secured to the steering column with a cable tie. I didn't use CBC9128 because I didn't want to chance the column lock locking the column while I am on the road.





The ignition switch plugged in and dangling below. I have it secured through the instrument panel light dimmer switch hole with a cable tie.

 

This is a photo of the JLM2145 Slave Cylinder as received and it works!





The completed assembly - new slave cylinder, new ignition switch assembled and easily installed. Total parts prices including shipping was about $220.00 USD.<br/>

I need to figure out how to reduce these pics down to thumbnail size...?

 

Much better, once again my new JLM2145 Slave Cylinder and my new ignition switch all assembled and working. total parts prices including shipping was about $220.00 USD.