Windscreen Fitting - Seal Quality Issue

[revilla]

Just got a new SV screen from Caterham via Auto Windscreens (insurance job) yesterday and came to fit it last night.

First thing to report is that the glass does not appear to be loose in the frame as some people have found recently so hopefully that issue is resolved. Screen still marked Tyneside Glass as usual.

I've done this a few times before so I knew what I was doing. Despite ensuring that the sealing strip between the screen and scuttle was properly locked into place in the channel at the bottom of the screen, and despite thorough lubricating the scuttle top with silicone lube spray, every single time I fitted it the seal popped out in the corners as shown below. This happened long before I came to pull them tight enough to remove the wrinkles round the corners.

After two very frustrating hours of repeated failure, not having had this problem before I realised that I had a length of the sealing strip in stock left over from when I had the scuttle off a few months ago. This sealing strip was bought direct from Caterham Parts. As soon as I compared the two sealing strips the problem was obvious. I sliced off a couple of cross sections as shown below.

The seal on the left was supplied with the screen. The seal on the right was what I had previously bought from Caterham. The installed seal was clearly generally smaller and thinner, the most noticeable difference being the T-section that clips into the bottom of the screen which was considerably less substantial and allowed it to pop out much more easily.

So I ripped out the supplied seal, clipped in the length I had on the shelf and, with some care ... it went in right first time!

I'm not sure if the seal that Caterham supply comes from a different supplier to the one used by Tyneside (I'm not even sure if Tyneside assemble the screen into the frame and fit the seal or just supply the glass). It could be that they have recently changed supplier. I don't know why the seal that came with the screen was so much less substantial than the seal I previously bought, but it clearly was.

I just thought I would post this up for information and as a word of warning to anybody who finds it unusually difficult to install a recently supplied Caterham windscreen!

[Jonathan Kay]

!

I replaced mine yesterday and the seal was fine, but I bought it through BC and I don't know where it came from.

From that fault I doubt if it would have made the critical difference but did you warm it to reduce the stiffness that wants to straighten it out of the curves?

Could you add the dimension, probably best across the T piece and the corresponding maximum across the bulge that goes outside. We can then share those for comparison. I'll try and find my bits in the bin.

Jonathan

PS: One preloved windscreen still available for a donation to NtL.

[Jonathan Kay]

Across T: 5.09mm
Across outside bulge: 4.99mm
Excellent fit.

Jonathan

[revilla]

Jonathan,

MEASUREMENT	SMALLER SEAL	LARGER SEAL	DIFFERENCE
T-PIECE TOP WIDTH	4.9mm	5.7mm	16%
T-PIECE TOP THICKNESS	1.3mm	1.7mm	31%
T-PIECE WAIST WIDTH	2.3mm	2.8mm	22%
BULGE WIDTH	4.9mm	5.7mm	16%

Although the numbers don't look that different, the T piece being almost 1mm wider and 0.4mm thicker actually makes quite a big difference to how tightly the seal grips into the channel at the bottom of the screen.

I've measured at a few points along a length of seal in each case just to make sure that it's not just manufacturing variation along the length but the measurements are very consistent.

I did try warming the seal but certainly with the originally installed smaller seal I was having more success with it cold as it gave a bit more rigidity to the T piece. I was actually finding I could install it fine, get all the screws tightened up, tension it just enough to remove the wrinkles whilst smoothing it down with my fingers ... then step back to admire my work and five or ten minutes later it would just pop out. Once it started to peel, it sort of unzipped along the bottom of the screen until there was a long section detached. It was all very frustrating, I've never had the problem before and when I used my larger seal it didn't happen again.

[Jonathan Kay]

I wonder if there are two specs: nominal 5mm and nominal 6mm. 

But are there two sizes of screen channel as well? Time and BC will tell.

Jonathan

[John Vine]

Andrew, I suggest you alert Darren in Parts.  He'll get on the case sharpish if there's indeed a supplier problem.

JV

[revilla]

Good call, will do.

[DJ.]

I thought it was me. I replaced a screen in the spring, and never managed to get the seal to fit anywhere near as well as the old one. Had to glue it to stay in the frame. In the end, I removed the seal from the old screen and re-used that.

[revilla]

Just for comparison, I ordered another length from Caterham Parts. Disappointingly it now seems they are also supplying the "smaller" seal that I had problems with rather than the "larger" seal they supplied previously.

Can anyone give me the contact details for "Darren in Parts" and I'll send him some info on what I have found.

Thanks.

[John Vine]

darren.phillips AT caterham.com 

01322 625811

Mob: 07801 977854

JV

[revilla]

Perfect, thank you.

[Nigel Riches]

I bought a length of screen rubber from Redline recently, and don't recall any particular problems installing it, other than general ham fistedness, certainly didn't appear to be any difference to the original item. may be a different profile, but I didn't do a cross section comparison.

Nigel.