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Seat bottoms on my 1970 2+2 are really worn out. Not the leather. The padding on the bottoms.. Anyone used these fitted foam inserts or had a local upholstery shop do their magic? This would make a huge improvement to driving comfort but I don’t know which way to go. As it is now it’s like sitting in a hole! 😊
I had the same problem with my '74 Siii. I felt like a two year old sitting in grampa's car.
A previous owner had replaced the seat leather, but the foam was not holding up well.
My understanding (from boat cushion replacement days) was that one could steam the foam and get back much of the original shape, but I'm pretty bad at re--stuffing anything. (don't ask me about pillowslips)
I took the car to a local upholstery shop. Fortunately, the owner had a lot of experience with collector cars. He immediately diagnosed the problem as a blown seat diaphragm. So I had him get parts and rebuild both seats with new diaphragms and foam. MUCH more comfortable ride!
I believe you can get replacement diaphragms a/w/a cushions online. The seats come out fairly easily, but I really wanted someone else to stuff them.
+1 on checking out the diaphragms as well as new foams. MANY videos available on how to do the seats, pretty similar to most other cars, some of the fastening might be a bit different, the tough part is pulling the seat cover material over evenly and getting it fastened.
Before covering, sit on the seats in place with the steering wheel adjusted to suit you. This is to make sure that you can get in and out of the car comfortably. If the foam is too thick, use a repurposed electric knife/slicer to help shave it down.
Cutting the foams down is certainly an option. Another alternative may be to drill the foams out. I just had this done to my seats. The replacement foams are far too hard, and end up raising you up so high that, in my case, my head ended up hitting the cabin roof in my 2+2. I took them to a mate of mine, and he showed me how to drill them out using a holesaw. He drilled a series of holes under the bottom foam, focusing on the center, and thereby removing some of the foam material. This doesn’t shorten the seats at all - they still have all the loft of the originals, and the outer portion of the foam is still just as high - but it does allow the centre to compress more, much like I suspect the factory seats did. I think the foams they make today are simply too hard, and that the original Dunlopillow foams were much softer, allowing you you to settle into the seat nicely.
Last edited by kmclemore; Mar 25, 2026 at 12:11 AM.
I found replacing the diaphragms to be the most challenging part. I inherited the replacement foam with the car, but I purchased diaphragms off eBay that matched the old ones in size, though they may not have been original. To secure them requires significant force to stretch them fore and aft to engage the attachment hooks. It took two people to hold the seat in place while I levered the hooks into the retaining holes. My predecessor employed fabric ties attached to the underside of the seat cover, pulled through the foam. This seemed superior to a recommendation to use glue between the cover and foam to ensure a contoured, tailored fit. Before fabric ties replacement foam new diaphragm w/fabric ties After
Oh yeah... those diaphragms are really tough to stretch. I restored the seats on my Sunbeam Alpine several years ago, and they have the same setup. I used a LOT of very, very, bad words doing that job! My wife held the seat frame while I used vice grips and a pry bar to get the links into their holes. It was NOT fun... you have my utmost empathy, IBC3!
When I did my Alpine seats I also added heated panels. It was quite easy and remarkably inexpensive. Only about $100 for the kit (Dorman brand), and I just used contact adhesive to stick them to the foams prior to applying the padding and covers. I routed the wiring and switches and wiring discreetly, such that they are entirely hidden, maintaining the 'original' look of the car, while offering modern comfort. Being a convertible, it makes the Alpine much more 'top down' drive-able in early spring and late fall.
That looks to be a very professional job you did. Seat warmers are hardly an issue here in Sunnyland; in fact, quite the opposite. We not only deal with keeping the car cool with upgraded radiators and fans, but we must also contend with overheated passengers. The limited "fresh air" intake is even more useless when the ambient temp is 90 degrees plus, and the road surface beneath the car is solar-like. As we speak, I am trying to design some kind of Rube Goldberg cooling system involving duct fans or standalone battery-operated coolers.
I notice an MG TD in your stable. That was my first car in high school (pictured) and the beginning of my descent into British car madness, and led to a series of MGs, Triumphs, Healeys, and an E-type just like the one I have now. (also pictured) From a classified ad in Wash. D.C.; $250, and it ran. Painted it with a brush. Joined the Marines, but it didn't fit in my duffel. Remained with my father until 1990. He became one of the founding members of the Jax, Fl. MG club, circa 1970, to which I recently joined with my MGA. Bought this last year because I was too cheap to buy a Jag, but it didn't scratch the itch. Got lured into bidding on BAT and ended up with "ReRun"...just like my first E back in 1971. What is it they say about insanity...doing the same thing twice expecting a different result?
A squandered fortune later, I often wonder "what If" I had bought the just then released 240Z instead of the Jag...
Per Yogi, "when you come to a fork in the road, take it".
Seat Bottom Foam Set…
