I am replacing the front and rear glass in the flared car when it gets back from paint.

I have read where the front windshield should use 3/8" butyl, but then there are warnings that this is a tad thick and if you don't have a warm day to press the glass into the butyl the trim won't click in.

I think 5/16" inch is a better solution. Does anyone have a source for 5/16" butyl? Does it really matter whether the rear glass is 3/8" or 5/16" since there is no trim just interior pieces?

Thanks in advance!

https://www.amazon.com/3M-Windo-Weld-Ribbon...5%2F16+windweld

Thanks Mark,

I even looked on Amazon - cheers!

Gotta know the secret code word, 'WindoWeld'.

Click to view attachment

McMark,

for the rear glass, I believed 3/8 is the original size but I read from few thread here that it is better to use 5/8? I did mine before with 3/8, but after few months I got water leak again.

Hi Noel,

I think 3/8" (10mm?) was original from what I have read in the workshop manual.

Anxious to see Mark's response. I think the glass might get close to trim piece with 5/8"?

Rear glass is spec'd at 8mm in the factory manual. So use 5/16" on that as well.

Nothing should ever use 5/8"

I can't find a specific size in the workshop manual. Just a part number.

But the manual does specify measurements for a setting-block tool, which indicates the installed/compressed thickness of the front butyl should end up being about 4mm. I doubt 3/8" butyl could compress this much.

Hi Mike and Mark,

For the windshield, when Rufino (from local here who did several 914 windshield) replaced my windshield, he used the gun type sealer and yes it is around 5/16" thick only that he applied and that is installing back the chrome trim.
Maybe when i did my rear glass, the 3/8 butyl i bought online (1 box) was old and it didn't stick well. I will check later the box of butyl I have or i didn't do a good job pressing it.

I used 3/8" on the rear glass of the Willow car, it was warm in the garage, butyl was VERY tacky and it was at least 10 years old that I bought from AA (was in a rear glass kit with blocks, butyl and a tube of cleaner). It worked great but I don't have any drive time on that car yet so I hope the glass doesn't fall out while driving... I put the seats it right after install and slid them back towards the glass with some towels in between the glass and the seats to "press" the glass in place. I left it that way for a week.

PS: I just ordered two rolls of 5/16" butyl for the front and rear glass - thanks Mark!

Don't forget to add the window spacers it will settle onto the metal and start pinching the seal. I suspect this is why they start leaking.
I do have as a re-seal kit including the butyl for $20
http://shop.914rubber.com/rear-window-reas...m?categoryId=-1

Or just the spacers for $4.50
http://shop.914rubber.com/914-Windshield-s...m?categoryId=-1

Mark - thanks for the update. I thought I saw the spacers were out of stock when I looked this morning. I will add them to my order.

I would never use the urethane gun type sealant on the front windshield. if any of it touches the trim you will have to ruin the trim to remove it. As I understand glass installers have to use it on all installs now by law. So get a friend and do it yourself if you can't get the glass company to install as originally designed.

I got mine at NAPA they have it in rolls and strips

It must vary by state. I had a new windshield installed in the Raspberry car a month ago and he used butyl. He said he hadn't used it in many years but if that is what originally came with the car he could do it.

Oh No Rick! mine was done last year with the gun type sealant! I believed several windshield from 914world local member was done the same. Well if in case I have to replace windshield again, maybe its time to use 914rubber rubber moulding instead of installing back the chrome trim.