1990 S3 S type start base strange shape causing sliding

[Aladoro69]

Does anybody have an issue with the old S type seats and a feeling of sliding forward?
It's as though the seat base shape is like a bowl with particular emphasis at the back
This seems to cause lower back/bum to rotate and slide forwards
It looks as though the foam inside the base at the back where it meets the seat back is too high and the centre section too low in comparison
It's bad for the driver but particularly bad for the passenger with nothing to brace feet against

Anybody experienced this and if so why fixes it workarounds?
Thanks

[BertBert]

Could it be that the foam in the seat (base) has rotted and needs re-upholstering?

The foam in my 90's bench seat bases was completely rotted away.

[Aladoro69]

Possibly
The only thing against that is that both seat bases are virtually the same and would be surprised if wear was so similar
Does anybody with S type seats have same feeling or not?

[BertBert]

But it's probably rot not wear. The two bench seats squabs on my car were equally rotten

[kitcat7]

I've had two cars with hose S seats, and noticed the same problem, which gets worse the older they get.

There are a couple of things you can do, the first and perhaps easiest, is to raise the front of the seat with spacers to tilt the base back, this will depend of your size and driving style of course, but worth playing with.

The other option is to either strip the cover off, and replace the webbing and maybe add strategic foam to support the front section and allow your bottom to sit to the rear.

It's not difficult to do this and worth playing around with to tailor it to suit you.

Perhaps let us know how you get on?

[Aladoro69]

Thanks
I stripped the passenger seat this weekend and it's definitely not rotted
Due to the way that the trim is attached the seat is one piece rather than later seats where the bases can be removed off the frame so can't move the base in relation to the back
Instead I've changed the angle with washers to lift the front as suggested, shimming start to runners and also runners to mountings
This improves things slightly by lifting the front up bit it's still an odd dished shaped
It's all though the rest most is fatter than it should be whish pushes bottom/base of back forward
Next will try playing with the padding