Seat diaphragm repair
Posted: Thu Mar 27, 2025 15:30
The rubber diaphragm supporting the seat foam on my driver's seat had split. Understandable, after > 200,000 miles, many of them bumpy, supporting 90-odd kilos.
Extensive searching failed to find either a new Lotus part, nor any from another manufacturer that looked like it might fit. I approached Newton Commercial, who supply similar items for more common cars, to see if they'd be interested in making them for us. They said they couldn't because the bought them in from another supplier, but when I asked who that was, so I could approach them directly, they refused to tell me. So I gave up that approach.
I've had a couple of goes at duct-taping the split diaphragm back together, but that doesn't hold for long.
So, at the Resto Show last weekend, I attempted a different approach. Time will tell if it is successful and durable.
I bought some rubber sheeting from Martrim - £9 bought significantly more than I needed. The sheeting was a bit thicker than the existing diaphragm, but not massively so. It's intended for flooring, so has a pattern on one side but is flat on the other.
I cut out two pieces the same size as the original diaphragm, and used contact adhesive to sandwich the original between the two new sheets. As a back-up, I drilled a number of holes through the sandwich and fitted rivets with washers through the holes. This left the original hooks sticking out along each side, so it could be re-attached to the seat frame.
With the extra thickness it was a slight battle to get the diaphragm back in place, but I managed it (with a little help from from my friends!). The seat was way more comfortable on the way back home, and has held up so far...
If anyone wants a go at this, I have enough rubber left over for at least one more seat. Yours for the postage, or collect. You can have almost an entire tin of contact adhesive too.
Extensive searching failed to find either a new Lotus part, nor any from another manufacturer that looked like it might fit. I approached Newton Commercial, who supply similar items for more common cars, to see if they'd be interested in making them for us. They said they couldn't because the bought them in from another supplier, but when I asked who that was, so I could approach them directly, they refused to tell me. So I gave up that approach.
I've had a couple of goes at duct-taping the split diaphragm back together, but that doesn't hold for long.
So, at the Resto Show last weekend, I attempted a different approach. Time will tell if it is successful and durable.
I bought some rubber sheeting from Martrim - £9 bought significantly more than I needed. The sheeting was a bit thicker than the existing diaphragm, but not massively so. It's intended for flooring, so has a pattern on one side but is flat on the other.
I cut out two pieces the same size as the original diaphragm, and used contact adhesive to sandwich the original between the two new sheets. As a back-up, I drilled a number of holes through the sandwich and fitted rivets with washers through the holes. This left the original hooks sticking out along each side, so it could be re-attached to the seat frame.
With the extra thickness it was a slight battle to get the diaphragm back in place, but I managed it (with a little help from from my friends!). The seat was way more comfortable on the way back home, and has held up so far...
If anyone wants a go at this, I have enough rubber left over for at least one more seat. Yours for the postage, or collect. You can have almost an entire tin of contact adhesive too.