Faulkner Posted September 12, 2022 Report Share Posted September 12, 2022 I have a '54 Plymouth Plaza Suburban. I've got a leak on both sides in the lower windshield corners in a heavy rain. The gasket itself seems to be in very good shape, and is pliable. Even if I could get a reproduction gasket (Bernbaum's, MoParPro, Roberts, Steele don't have it), I'm told that nothing is better than the original. I thought I had fixed it by tucking plumber's putty under the glass-side lip, but the leak persisted. I scraped it out, and next I tried a bead of 3M bedding caulk around both the inside and outside perimeter of the gasket, as shown in the picture (I taped it off first). Still no love; the bedding caulk has now been removed. I thought I'd try one more thing - using a tuck tool, prying up the glass-side lip and pushing in a bead of black urethane, and running it around the outside perimeter as well. I thought if I took some wide painter's tape, and straddled the glass-gasket border with it, I could use a razor blade to divide on the border; after I've filled the gap with urethane and struck off the excess with a popsicle stick, I could then just strip off the tape to minimize the mess. What are your thoughts about this? What have others done? Dan Quote Link to comment Share on other sites More sharing options...
andyd Posted September 12, 2022 Report Share Posted September 12, 2022 I've always used a black windscreen sealer called windscreen mastic.........it should be used between the rubber seal and body on the outside and also between the rubber seal and glass on the outside.........mastic stays pliable which is why its a better bet than silicon or any other sealer that hardens........our old cars rubber to body "interface" was never perfect and the non hardening mastic filled the gaps & stopped water entering............my Oz 2 cents worth...........andyd Quote Link to comment Share on other sites More sharing options...
Faulkner Posted September 12, 2022 Author Report Share Posted September 12, 2022 I googled it, but can’t find it. Have a link? If it’s not urethane or silicone, what is it? Butyl? I’d like to check some reviews. Quote Link to comment Share on other sites More sharing options...
Faulkner Posted September 13, 2022 Author Report Share Posted September 13, 2022 2 hours ago, Faulkner said: I googled it, but can’t find it. Have a link? If it’s not urethane or silicone, what is it? Butyl? I’d like to check some reviews. Ah, you're Down Under! I found it: https://smitsgroup.co.nz/product/60160/holdfast-bison-windscreen-mastic-sealant-300ml-black Still, it says it's a polyurethane base; I'll probably stick with the 3M product, if urethane is the way I should go. Dan Quote Link to comment Share on other sites More sharing options...
andyd Posted September 13, 2022 Report Share Posted September 13, 2022 I dunno about the polyurethane bit but this stuff is what I've been using for about 50 years(yeh, I'm that old......lol).......it does eventually harden but its definately not a silicon type of sealer.....well at least thats what I know it to be.......but use whatever you feel comfortable and familiar with as I'm no expert ......lol.........andyd Quote Link to comment Share on other sites More sharing options...
kencombs Posted September 13, 2022 Report Share Posted September 13, 2022 (edited) I think the US version would be a 3M glass bedding compound. 08509. I think if that is a lock strip I see in the pic pulling it out would make it much easier to get the bedding stuff under both the glass and metal side. But you may need a new lock strip. in my experience any urethane product will be a one time deal. Can’t be removed with destroying the rubber Edited September 13, 2022 by kencombs Quote Link to comment Share on other sites More sharing options...
Faulkner Posted September 13, 2022 Author Report Share Posted September 13, 2022 41 minutes ago, kencombs said: I think the US version would be a 3M glass bedding compound. 08509. I think if that is a lock strip I see in the pic pulling it out would make it much easier to get the bedding stuff under both the glass and metal side. But you may need a new lock strip. in my experience any urethane product will be a one time deal. Can’t be removed with destroying the rubber Yeah, 3M 08509 bedding compound is what I used around the perimeter, i.e., without actually forcing under the lip. A tight bead, taped off, top and bottom; it still leaked. The US version would probably be 3M 08693, a urethane compound. I think that's what I'm going to try next, this time forcing under the lip, at the risk of destroying the rubber. My hope is that I won't have to remove it, because it worked. BTW, there is a lock strip, but it's on the inside. Removal might make it easier to get compound between the pinch metal and gasket, but I think my trouble lies between the glass and the gasket - and I don't see removing the lock strip helping there. Quote Link to comment Share on other sites More sharing options...
vintage6t Posted September 13, 2022 Report Share Posted September 13, 2022 I've had good luck sealing leaks around my RV window frames and other areas with Lexel sealer. First learned about it from an RV forum. https://www.amazon.com/Sashco-13013-2-Sealants-Adhesive-5-Ounce/dp/B0012DIUYW Quote Link to comment Share on other sites More sharing options...
andyd Posted September 13, 2022 Report Share Posted September 13, 2022 These are the only 2 pics that sort of show the mastic........its between the glass and rubber and between the rubber & body.........and the centre bar shown is my home made centre divider using brass bar and rod, soldered together then chromed, made it 45 yrs ago......its the only centre bar I know of that hasn't broken or cracked..........lol.......... .regards, andyd Quote Link to comment Share on other sites More sharing options...
Faulkner Posted September 13, 2022 Author Report Share Posted September 13, 2022 1 hour ago, andyd said: ... the centre bar shown is my home made centre divider using brass bar and rod, soldered together then chromed, made it 45 yrs ago......its the only centre bar I know of that hasn't broken or cracked. Nice job on the center divider, Andy! And thanks for the mastic pics. Quote Link to comment Share on other sites More sharing options...
kencombs Posted September 13, 2022 Report Share Posted September 13, 2022 IME the mastic must be under the rubber to work. The urethane versions will either work or require replacing the rubber seal if they don’t as they are almost impossible to remove. I have an older motor home that was treated to that ‘repair’ by a tech that was supposed to be expert in that area. Cost me well over a thousand bucks to replace the seal Quote Link to comment Share on other sites More sharing options...
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