Wow, very strange the reports about continuing problems after the TSB fix was made. If you understand how the drive is designed there is only rotational force being applied on the wound cable and delivered to the screw mechanism on the headrest assembly. The best example I can draw is it is the same as an old fashoined speedometer cable. The housing, or sheath is only keeping the rotating cable supported so it doesn't wind itself all into the seat material. In theory (not practice) the drive mechanism would work without the sheath. There is literally no pressure, tension or rotational tension being applied to the sheath under normal design or operation, only flex of the entire assembly higher where the screw mechanism travels some verticle distance.

The sheath, by its length does govern how far the cable will travel into its square sockets on both ends. Two extreme conditions can exist, one of which does and caused the TSB to be issued - The sheath can be too long thus allowing so much float of the cable in the sheath as to cause one of the square drive ends to fall completely out of the drive. The second is the sheath is too short. This would eliminate all cable "float" and cause binding of cable as its drive ends would be forced under pressure into its drive sockets. There is only so far you can go in the direction of too short before the drive would no longer physically assemble, and with the splice, would separate it.

I can make a couple of suggestions as the TSB was never clear about where to make the cut/splice. The cable sheath assembly has some movement closer to the top where the headrest screw travels, but it stays pretty verticle lower, closer to the drive motor. I put the splice closer to the drive motor, not the headrest end. Perhaps the separation is occurring because the cable/sheath is bending during headrest operation and bending/breaking the splice if you made it too high on the cable?

Second possibility - too large a splice was made making the sheath too short. NOW you have a compression/tension problem on the sheath. This wouldn't cause the splice to separate, unless the cable started unwinding and growing in length. THEN the weak point in the sheath would be the splice.

Third possibility and could be part of the second- based on how the cuts for the splice were made, if the wound cable was left in the sheath and it was knicked or damaged by the cutter, the cable is now unwinding during headrest operation and destroying the sheath.

My suspicion is probably the first possibility. Hope this helps as you shouldn't have to be doing this repair more than once.

 

I meant vertical - too early in the morning.

 

Steve,

I made the spice just a bit north of where the cable fits into the drive motor (almost exactly as shown in the TSB and also in the step-by-step fix that was sent to me by Steve Hannes). You are correct, the actual drive cable is just like a speedometer cable. After the second time my fix started failing, I kept my fingers around the splice to feel what was going on as I operated the headrest. I think that the spin of the actual cable does cause minor movement in the overall cable+sheath assembly. Also, the vibration and bumps from normal driving and sitting on the seat will eventually cause the splice to separate as time goes on. This can be prevented by using either really tight and adhesive lined shrink tube (the shrink tube I used is not all that tight and/or I did not have the right tool to fully shrink it) or you may get better results by using electrical tape.

Another obviously more expensive solution would be to see if a replacement cable/sheath assembly if available from Jaguar (assuming a replacement that is the correct length is available)

Doug

 

If you come apart again, I'd consider using electrical tape then. Maybe that is the secret to my success and I just don't know it. Maybe do several spiral wraps, then consider clear lacquering the tape. The lacquer might keep the tape from eventually unraveling.

I know Steve Hannes. I collaborated with him on an X-Type project when he was in Colorado. He's a heck of a good mechanical engineer. He actually redesigned some X-Type transfer case parts to eliminate the viscous coupler and disable the FWD. Where do you know him from?

 

I don't really "know" Steve. But when I originally had the headrest problems I was searching around all of the various Jaguar forums and found him on the Jag Lovers forum. He had posted some information about the headrest fix and was nice enough to email me a narrative along with some photos he took while doing the repair. I had taken the stuff he emailed me and assembled it into a single document which I have forwarded on to others (and may also be a sticky in the FAQ section here). So basically we just corresponded with each other a bit about details of the headrest fix.

Doug

 

First failure for me WAS the electrical tape. Heat made it lose its adhesive property, and twisted the splice apart eventually.

 

I am wondering if the dealer still fixes this the same was as described in the original TSB or if Jaguar finally come out with a replacement cable/sheath assembly that is the correct length?

Doug

 

Thanks for all the great info on this topic. I just fixed both seats using a combination of heat shrink and electrical tape. Hopefully I won't have to revisit the problem

 

Does anyone have the step by step instructions, with pictures, that are referenced in this forum? I would very much appreciate it if you'd send them to me if you have them. Thanks!

 

It is here: http://matt.zenfolio.com/xk-headrest-tsb.pdf

It is also out now on video here: https://www.jaguarforums.com/forum/s...ad.php?t=40347

 

Andrew..I just noticed from your previous posts that you may have an XJ Super V8, not an XK8 or XKR. If this true, this headrest info is not applicable to you and you should post your issue in the XJ forum.

 

"Out on video" LOL!!! It was actually a low-budget, direct-to-video release! I pitched it to the big studios, but they weren't interested.

 

Rev, next time try the casting couch

 

LOL! Have you seen what I look like? Youtube would ban my videos if I showed my face!

 

Over a year ago I repaired mine and used "Gorilla Tape" (a heavy duty black duct type tape that we use in our shop this stuff really works.) I make it a practice of operating the head rest every chance I get. All though the car isn't used in the winter and is not a everyday driver I don't think the Gorilla Tape will unravel.
Rev Sam-Face Book will let you on, you've seen what they allow. Besides just sitting in your "Cat" makes you 10 times better looking.
Doug
2001 XKR Silverstone

 

On my first attempt to do the repair I used the Gorilla tape. Unfortunately the glue softened in the heat of summer. My second attempt is what you see in the video.

 

Looks like I'm bumping this up to the top after a little while.

First things first, thanks to everyone that has contributed, its made my life so much easier coming along after! Also Rev Sam they say a picture is worth a thousand words, so I figure that makes your video worth every TSB in the world!

I'm doing this fix on both driver and Passenger seats. The issue people seem to be having with the heatshrink or electric tape not holding got me thinking about alternatives. On a few other repairs/bodge-jobs I've used self vulcanising rubber tape, basically a flexible/expandable rubber tape that seals to itself to form a very strong join, I can't see that it would be effected by temperature extremes the the same degree as shrink or electrical tape. Anyone tried that yet?

Cheers
Russ

 

Our 2006 XK8 convertible was delivered to our house last night. Beautiful car, my wife loves it. She's out driving around right now with a big grin on her face....

Just a few issues, and the headrest problem is Issue #1. The drivers headrest works fine. The passenger headrest is stuck in full-up giraffe position. It is driving my wife nuts. The motor runs, but no headrest movement occurs. Is the problem always fixed by the electrical tape / sheath approach covered in this thread?

My wife would be happy if I could just get the passenger headrest to drop to the full-down position and stay there. Is there a way to do that without taking the seat apart?

Thanks for any input those of you who have already been through this issue can add....

 

Should you want to lower the headrest without repairing, you will essentially have to do everything that has been described in the posts with the exception of cutting the sleeve and making the repair. Once the vertical backrest of the seat is removed or rolled up to access the motor, you can disengage the cable from the motor and turn the shaft (by hand or mounted to drill) to lower the headrest.

 

But if you go to all that trouble you might want to take the extra 5 minutes and do the sheath resizing!

Doug