Page 1 of 1
Can you help? Where can i obtain a 'mastic retention dam'??
Posted: Mon Jun 03, 2013 4:35 pm
by steve75598
My '88 convertible (vin 150163) has developed an MOT failure crack up the windscreen. Apart from autoglass turning up with a coupe windscreen in April
they and I have failed to find a 'mastic retention dam' for the last 2 months..... so she's sitting unused in the garage sans MOT
Jaguar no longer stock this part.
I'd be eternally grateful for any info that could get her back on the road again
Many thanks in advance.......
Re: Can you help? Where can i obtain a 'mastic retention dam
Posted: Mon Jun 03, 2013 4:59 pm
by Brakebuster
any reason why your existing one cant be reused ?
had a look at the part, and as you know NLA ,
BB
Re: Can you help? Where can i obtain a 'mastic retention dam
Posted: Mon Jun 03, 2013 5:26 pm
by steve75598
Thanks BB. It may be usable, all depends on skill of autoglass technician - and I think they always want new for guarantee purposes .....
Re: Can you help? Where can i obtain a 'mastic retention dam
Posted: Mon Jun 03, 2013 7:00 pm
by ptjs1
Steve,
The two key elements when replacing the screen in an XJS are:
- making sure there is absolutely no corrosion in the windscreen flange
- ensuring that the fitter is very experienced in XJS windscreens
You may recall my article in the mag about 17 months ago where the potential horrors of flange corrosion were shown.
Forgive me if you've already done this but I would start the process by carefully removing the chromes, then get the fitter around to remove the screen as an initial step, before you decide how much remedial work may be required. Don't even think about fitting a screen if the bodywork flange is anything less than perfect.
A good fitter should be able to reuse the mastic dam. Perhaps the best way is to contact some of the Jaguar bodywork restoration companies in your area and ask them who they use to remove and refit XJS screens. If the Autoglass fitter has not done a number of XJS screens before, don't let him anywhere near your car!!
I hope that hasn't depressed you!
Good luck
Paul
Re: Can you help? Where can i obtain a 'mastic retention dam
Posted: Mon Jun 03, 2013 7:38 pm
by steve75598
Hi Paul,
Many thanks for your warning.... this could take longer than I thought! I do recall your article - vividly! It made for sober reading. Hope all's OK now. Strangely, I hope body flex was the cause, but we'll see. I'll keep you posted.
Cheers
Steve
Re: Can you help? Where can i obtain a 'mastic retention dam
Posted: Mon Jun 03, 2013 8:04 pm
by ptjs1
Steve,
The bonding of the screen is an integral element in providing some torsional rigidity to the body. If it was body flex that caused your crack, sadly it might imply that the sealing was less than perfect. On my car, it was clear was that there were small sections of the screen where there was no sealing intact between the glass and the seat. I suspect this is primarily a Jaguar build quality issue coupled with the inevitable hardening and drying over 15+ years. As you will appreciate, it only takes a minor failure to allow minute water ingress which can work away hidden behind the rubber cover and chromes.
For the sake of a few extra quid, I would definitely find a good quality fitter and get the screen out first and take your time over the whole job With luck, the flange may just need a clean and paint touch-up. Only when you're happy with everything would I get the fitter back to fit the new screen.
You might also find that even an experienced XJS screen fitter will not have fitted the cover chromes before. They are more difficult to put back than they are to take off. Correct alignment needs real care and you will need to use masking tape or similar to hold them in place during final setting.
As I said, talking to Jaguar restorers / bodyshops first could be a good start.
Good luck, Steve
Paul
Re: Can you help? Where can i obtain a 'mastic retention dam
Posted: Mon Jun 03, 2013 11:00 pm
by steve75598
Sound advice Paul, thank you. I promise to be patient, after all, the car is a keeper.
Cheers
Steve
Re: Can you help? Where can i obtain a 'mastic retention dam
Posted: Wed Jun 05, 2013 8:22 pm
by davidr
Steve - you might like to try Hollygrove Jaguar in Ringwood (01425 477000). They did a bodywork restoration on my 1989 V12 Coupe which included taking out and refitting the screens. I think they got a specialist in to do it who has experience with the XJS.
Regards
David
Re: Can you help? Where can i obtain a 'mastic retention dam
Posted: Wed Jun 05, 2013 9:24 pm
by steve75598
Many thanks David, for taking the time to reply. Will do. The beauty of the forum

.
Regards
Steve
Re: Can you help? Where can i obtain a 'mastic retention dam
Posted: Sat Jun 15, 2013 4:49 pm
by davidr
Steve - did you have any luck fixing this?
Regards
David
Re: Can you help? Where can i obtain a 'mastic retention dam
Posted: Sat Jun 15, 2013 4:59 pm
by steve75598
Hi David,
Since we last spoke Autoglass failed to (a) find a rubber and (b) failed to turn up when booked and (c) were adamant the rubbers could not be reused. In the meantime I spoke to KWE at Greenham Common ... and they managed to locate the 'trim' rubber yesterday via a contact in the Jaguar dealership network. They bought 2, one for their stock - about £40 each. They also recommended A & B Windscreens in Andover who "seem to be able to get over the problem of not having a mastic dam". I intend to call them on Monday to ask a few questions. Looking a bit more positive
Keep you posted.
Cheers
Steve
Re: Can you help? Where can i obtain a 'mastic retention dam
Posted: Sat Jun 15, 2013 5:02 pm
by steve75598
Hi David
I did speak to Ringwood as you recommended - they were going to let me have the details of an 'old boy' Autoglass fitter they use. So, I have a choice; always a good thing.
Many thanks
Steve
Re: Can you help? Where can i obtain a 'mastic retention dam
Posted: Sat Jun 15, 2013 5:15 pm
by davidr
Steve - sounds like you're onto some possibilities. Bear in mind that the job may not be as simple as replacing the screen as very often there is corrosion around the windscreen aperture and this has to be dealt with before the new screen goes in or you'll be wasting your time and money!
Keep us posted - I'll be interested to hear how you get on
Regards
David
Re: Can you help? Where can i obtain a 'mastic retention dam
Posted: Sat Jun 29, 2013 10:08 am
by steve75598
Hi All,
Well, the new windscreen is now fitted and MOT booked.
KWE at Aldermaston have a tame fitter they use - Nigel at A& B Windscreens - who really knows his stuff.
http://www.abwindscreenshampshire.co.uk/
KWE also managed to locate the 'out of production' windscreen rubbers from one of their contacts - who had 2 (they bought both - one for their stock).
The set up this car has is that the chrome trims do not need to come out to replace the screen, so that was some simplification and a huge relief. The old screen came out easily enough - and yes, the expected corrosion was evident. Luckily it not serious and in the main superficial. It appears that sometime in the past the car had a replacement screen - it seems the fitter had scratched the flange paintwork on removal and had not touched it in - so after another 10 years or so the inevitable had occurred. I arranged for Nigel to return in a couple of days, leaving me time to complete the repair.
The new rubber fitter the screen perfectly and the only other thing required was the bonding material that Nigel applied with that looked like a large bathroom mastic applicator with a cake icing mechanism on the end that formed an L shape black 'rubber' on the flange. Pop the screen in, jiggle it around a bit and job done.
Nigel did a grand job and is recommended to Club Owners. He specialises in old Jaguars and has 25 year's experience to call on. He's a bit of a petrol-head too, with a Norton and a Mini Cooper in restoration.
So, thanks to the forum another successful job completed and another new contact made.
Cheers
Steve