The easiest way to do it is scrap existing window rubber. Cut the inside lip out with a stanley-type knife (watch your fingers and anywhere else!). Screen will lift out easily. Two people best but you can do it on your own if careful. Set the screen aside somewhere safe - very safe. Remove remaining rubber.
Go to local £ shop and get a rubber mallet and a length of their braided nylon washing line - you'll need it for the refit.
Get damage welded. As I said in WIKI you can do it with dash in but remove mats, ideally front seats or at least protect/cover seat with boards or similar to protext from grinder or welder sparks. Make good paintwork. Allow to dry.
Fit new GOOD rubber to screen, feed in washing line into rubber - right into groove where windscreen lip would go, overlapping the rope by a foot or so in the middle. Ensure any headling on van is tucked in so it won't be left out when screen is in. Use instant glue if you have to.
Line up screen with vehicle, apply gentle pressure to outside to help ease screen and rubber into place. tapping very gently with the mallet on window rubber to push it home as you pull on rope from the inside. Its actually easier to do than explain. You need enough pressure to push screen home but not so much you're fighting to pull out rope. Again go round rubber with the mallet and make sure screen is fully bedded.
Do this job with a JK rubber and you'll fight all the way - if it ever goes in, even with an army to assist you. Do it with the right one (that actually fits) and you could definately do it on your own - I did. The only reason you need a second person is to help maintain pressure from outside and to stop screen falling off. I just hopped in and out and managed fine.
I used B&Q roofing mastic (just cut small nozzle) under outside lip after fitting to ensure watertight seal. White spirit removes any excess. Your choice on that - it just worked for me. I'll let the purists argue over it until kingdom come, but as it clearly lets in water over time without mastic, I'm for the mastic.
I've changed well over 20 screens now and never broken one. Once its back in, you'll wonder why you were so fearful. Ignore the scare stories. Rocket science this isn't.
Do the removal/refitting yourself and welder will be really happy. It'll keep costs down too.
I've shown how its done. Its all there:
https://club8090.co.uk/wiki/Bo ... well_leaks" onclick="window.open(this.href);return false;
Heres the difference between seals:
First the JK 'thyroid' El-budget version:
And trust me, they are a complete PIG to fit. In fact its easier to fit a pig. It also bulges out horribly. Its just a naff seal.
Now the Emporium 'flush' and properly fitting one:
I put Mick on to these and he won't use anything less either. Any financial saving is lost in the times you'll end up saying "Why the hell didn't I fit a proper one" afterwards. You'll be stuck with it then. 1664 popped over and had his thyroid seal replaced for a proper one. He wasn't impressed with JK ones either. No disrespect to JK as they do some good stuff and often provide a good service but their seals suck in my view. I wouldn't buy them. The bay window ones were not much better.