Arse falling through the driver’s seat
 

Well I’ve a sensitive bottom and my left cheek felt a bit lower than usual in my 1999 XK8.

Took a peek under the seat and...

https://cimg4.ibsrv.net/gimg/www.jag...7ebaec547.jpeg

Seems like the rubber support had split. So with the help of my young helper, I took out the seat and...
https://cimg7.ibsrv.net/gimg/www.jag...d27f6a022.jpeg
... the spring rubber “arse” support panel had split...

Bugger! Must have been eating a bit too much over the winter

I need to check mine after seeing your pics. I'm sitting a bit low as well.

+1 here too. Wonder if we can figure out a fix.

John

What about replacing the rubber support? Could a flat metal bar work or would that be too uncomfortable?

Strike 1 - epoxy and tape repair - no good
 

Well, my first fix didn’t hold.

My young helper used 2 part epoxy in the rubber year, and tape over the split, and it didn’t hold. Not surprising as rubber diaphragm takes your full weight in tension

Onto plan B. Try donor scrap car seat diaphragm.

Plan C is to Swap the passenger seat diaphragm to the driver’s seat, then try to get better repair.

So David, sounds like you've found that it is just the rubber that's worn? No stretched springs or anything? Just confirming, thanks.

John

I just googled "rubber seat diaphragm Jaguar ". Wow there are a ton of options out there. OTOH none seem to be specific to XK8 or X100 models. David since you have eyes on it, let me ask: could you post dimensions? Is that a meaningful request? ( I can't imagine the dimensions or shape)

I look forward to your thoughts.

John

I just had to replace the one in my 1967 MGB GT and the replacement diaphragms available don't fit (too small, rip when you try to tension them). I ended up just using black nylon "lawn chair" webbing and pop riveting to the seat frame. Not sure if that would work here but it works on MGBs.

My 2004 has a spring loaded wire basket that spans across. Way different than earlier years. Interesting how over the years things were improved that you would never expect.

Perhaps you can fit something similar in the older seat frames.

Rothwell - Things are certainly different on later Gens
 

Geez, never realised that saggy bottoms were such a problem that Jag had design upgrades during the X100 model line.

Rothwell - your spring basket is fixed front to back on the frame, while my rubber diaphragm is sprung left to right. Wonder why?

Guys- When I next get the part out I’ll take some photos and dimensions. I’ll update this thread to let you know how I get on.

BTW there’s a lot of wires beneath the seats, plus motors and remember the seat is heated. You can’t just put in any foam, as it’ll be a fire hazard. Think my next bet is a visit to an upholstery specialist

Eid here - working on broken seat diaphragm
 

Well here’s a pic of the broken rubber diaphragm with side hangers. Getting to it was easy.

Easier access removing the entire seat out the car. 4 T40 bolts hold the base mechanics to the car seat but you need to fully raise seat first for access to back 2 me T40.
https://cimg4.ibsrv.net/gimg/www.jag...1dc66227f.jpeg
Rubber measures 11”x10 3/4”

https://cimg6.ibsrv.net/gimg/www.jag...a15dc48d3.jpeg
Comparison of the broken driver seat’s diaphragm and one from the passenger seat. Identical size.

Could it be stitched?

Trying Cabel’s (post no8) suggestion
 

Went to plan C - swapping good passenger side with driver’s side.

At leisure now, I’m Trying this home DIY fix first
https://cimg4.ibsrv.net/gimg/www.jag...c4c0fe4c7.jpeg
Will redo epoxy and tape with additional support. Using a broken office chair, I took the seat’s webbing and will try to glue/staple the webbing to the XK8’s seat diaphragm to reinforce it. Not sure how that will turn out..... Still zero dollar repair....

If this doesn’t work may be a trip to specialist upholsterer to try the stitching ....

As expected the part is NLA .... F)£k! Bugger! Arse! LOL

Good idea. Let us know how it works. And I would leave it on the passenger side....

I would also consider sewing the new webbing to the old material using something like monofilament fishing line or heavy-duty seam stitching to provide additional strength along with your glue and staples. You may want to consult a retail sewing/fabric store for the best "thread" to use in this application....

BTW, how is the edge webbing terminated on the rubber? Can we use that as any type of model to repair? Great photos BTW.

John

David, was researching this. Lots (and lots) of diagram for older jags, Triumphs, and MGs out there. Took some time to read some comments. A lot of those guys are using webbing to replace or augment split diaphragm. Some even mentioned the webbing from old lawn furniture. How well does it work? Feedback overwhelmingly positive but vast majority of the positive comments say it's an improvement over the rubber. This says it's not the same, you "sit a little higher". Before that shuts you down, I should note that the worst rating about the webbing said it was the same comfort wise.

Thought you might find interesting. If you're in a bind, maybe it will work...

John

Heated Seats droopy
 

This is a very interesting thread, and probably applies to a lot of cars, if not now, then ....eventually. I'm a little curious, since I haven't had my seats out - is the seat heating element above the rubber "sling" ? I guess it must be.

ABS sensor and heating element built into the seat cushion
 

Jimmy L

The seat’s support diaphragm is on the bottom below the cushion foam and above the seat’s travel motor, worm gear etc mechanisms. There was a cable that led into the seat cushion and I presume that is for the heating element. There’s also an airbag pressure sensor built in the seat cushion above too.

Recently, before the repair switch, I’ve been getting a flickering Airbag warning, which seemed to go away when I wiggled my left buttock cheek trying to get comfortable. Putting two and two more together, my broken seat diaphragm was the cause as I wasn’t getting pressure on the airbag sensor. There’s been previous threads on how this airbag sensor is delicate so I didn’t want to take off the seat cover as the leather condition is fine. I may go with Rothwell’s additional foam on the bottom.

Jimmy your 2006 most likely will be same as my 2004 that uses the metal sling basket instead of the rubber belt unless Jaguar made even more improvements.

I highly recommend adding the layer of foam between the original foam and whichever style sling your car has. My seat bottoms no longer have that ass imprinted saggy look and are more comfortable for sure.

the seat heating element sits on the upper surface of the seat cushion