This post was written by forum member -halli- please direct any questions directly to -halli- and not to Forum Technical.
When replacing my well worn out vinyl hood for a nice new mohair one, I noticed the door seals were past their best and had already been modified by the previous owner. After seeing how much some new seals would cost me I decided to have a go at saving the old ones – what did I have to lose?
I searched the net for some foam tubing to use inside the seals to beef them up a little. I found this and couldn’t resist! 
11mm OD and I’m going to use it to wrap around the cables in the doors to stop the rattles too. I only got 800m of it, so I might start selling it on when I’ve used what I need 
The previous owner had used cut up scouring sponges in the corners and lots of black roof sealant stuff which was too hard for the job. The sponges were a bit wet on one of the seals too where water had got in. 
The previous owner had already made the necessary slits at either end, so once I had removed the soggy sponge and hard sealant I just slid a length of foam tubing into the gap. I then cut a length of foam tubing along the middle and slid that in too (as two tubes wouldn’t fit, one and a half is perfect) I used about 4m of the foam tubing for all of the seals. 
I then used some neoprene glue (ebay) to seal the slits. Smear it on the edges, leave it to go tacky and then hold the two edges together for about 1 minute (I used clothes pegs) 
I finally smeared some more neoprene glue on the top of the slits to ensure they are watertight. 
There were two splits in the seal on the edge which the neoprene glue has sealed perfectly.
I’m fitting them to the car tomorrow after the glue has had time to dry and I’ll report back to let you know what the fit is like.
Well, I fitted the seals today (I have been putting decking in the garden all weekend and only finished today - why do Jewsons close at 12:00 on a Saturday?)
Now they press nicely against the glass and don’t deform as much as they did before. The joints between the seals are very tight now.
I am a happy -halli- 
Well worth the effort (and a hell of a lot cheaper than replacing the seals.)
I was thinking of selling the foam at about 30p per metre plus postage. I reckon about 4-5 metres to do the job so about £1.20 - £1.50 plus postage. Does this sound OK, I don’t want to rip anyone off.
Like I also said, I’m going to try to use it to cover the cables in my doors as they rattle like mad (and vibrate to loud baselines)
Just to add to the above (should have put this on earlier)
When you put the seals back on make sure you adjust the metal runners to suit the foam filled seals.
I thought I would need to move them further away (in towards the car) but strangely it was the opposite. I had to move them outwards towards the glass.
Looking at the seals on the car, you might get away with putting two strips into the seal, rather than one and a half like I did. Best thing to do is try it out and see.
Glue might not be necessary either if the slits are meant to be there, making it an even cheaper (and reversible) fix.
The foam costs £3.50 for 5m (inc post) and you can get my -halli- Paypal address via PM.
10m - £5
15m - £6.50
20m - £8