HOW TO: Fix your leaky windshield (1 Viewer)

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Did mine 3-4 years ago, holding up fine here.

How is this product holding up for you guys after all these years? Also, any tips on doing this with a snorkel installed...seems pretty tight in that area where the snorkel mounts by the windshield gasket.
 
Man... I'm hoping this is my issue. Everytime it rains I have that 'sloshing' sound coming from the front right door/quarter panel area. I have cleaned the slits, ran weed eater line down the sunroof drains, taped up a straw to the end of a fuel line taped to the end of my shop vac and vacced out the sunroof drains (nothing came out), looked around inside for rust (surely there should be some rust/sign if there's standing water inside my quarter panel a few times a year). My passenger floorboard is constantly wet.

Thanks to this thread I started feeling up behind the dash on the firewall and felt a slight dampness. So maybe resealing my windshield is next. I've pulled the plastic drain plugs on the passenger front side as it's supposed to be pretty wet here in TX the next few days. I'm hoping that at least the sloshing and standing water issue will go away. I've pulled the carpet up around the edges as much as possible without pulling it up from the original jute/pad layer hoping to let it dry out some and have a better view of where this water is coming from.
 
The water won't pool in the rockers if the slits are clear. You must not have cleared them sufficiently. Leave the plastic plugs out for a while and see if the problem disappears.

If your rockers are full of water, the sunroof drain tubes won't work correctly. If the lower ends of the sunroof tubes are below the level of the standing water in the rockers (and yours may well be), a bubble of air gets trapped in the tube somewhere in the middle and water won't drain into the top drain holes and just fills up the sunroof trough until it finds its way in.. It is like holding your finger over a straw.

Get the water out of the rockers first, then assess how to allow them to drain reliably (leave plugs out, extend tubes out of rocker). Once that is done you may find that your windshield is okay after all. If not, seal it up like these guys have done.
 
If you dont clean the rockers first, as Dave is mentioning above, the water will not drain. You can have a lot of water there with some caked mud preventing drain. I use the same line to clean the sunroof drains to clean the rocker panel drain. This was my passenger side recently

 
The water won't pool in the rockers if the slits are clear. You must not have cleared them sufficiently. Leave the plastic plugs out for a while and see if the problem disappears.

If your rockers are full of water, the sunroof drain tubes won't work correctly. If the lower ends of the sunroof tubes are below the level of the standing water in the rockers (and yours may well be), a bubble of air gets trapped in the tube somewhere in the middle and water won't drain into the top drain holes and just fills up the sunroof trough until it finds its way in.. It is like holding your finger over a straw.

Get the water out of the rockers first, then assess how to allow them to drain reliably (leave plugs out, extend tubes out of rocker). Once that is done you may find that your windshield is okay after all. If not, seal it up like these guys have done.


Yeah, this is my plan. Rain comes in tonight so I'm hoping over the next few days I can find out exactly whats going on.
 
Alright. Got a little time before it rains be to recheck the drain slits and check it all out again. Seems like I can’t get the weed eater line all the way through the sunroof drain tubes, but pulled the bottom out and put it in a bowl and tested with some water, and they drain.
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But a question about the windshield gasket. Should it cover up the metal door in the windshield opening more than mine does? It looked to me like it wasn’t seated all the way and could potentially be a spot where water could pull. I see faint hits of rust around the windshield gasket, so I’m thinking when I paint soon I may just order a new one and pull the windshield when I paint.


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With sealant installed per the FSM there is no reusing the seal because same FSM calls for cutting it out with piano wire when removing the glass. If the seal is reusable it was not installed correctly in the first place. I suspect over 90% of us are/were driving around with improperly installed glass if it was replaced previous to ownership. Pry up the edge of the seal and take a look if you are unsure.

THIS!!
Found unsealed front seal after seeing little puddles in the lower corners of the windshield. Just jumped to the top of my to do list. Seal seems pliable enough, so I'll finish the PO installer's job.
Cheers! :beer:
 
UPDATE: This fix is still working, it's bone dry 3+ years later.

I had water leaking into the cab from the windshield. It was a replacement windshield that was in the truck when I bought it. It didn't have the sealant/adhexsive as specified in the FSM. I noticed the carpet in the driver footwell was damp in the corner, and I would actually feel a drip on my foot from under the dash on occasion. Looking at the bottom interior corners of the windshield, I could see moisture, or a tiny puddle, in the corner where the windshield met the seal.

So, the water was leaking from the outside, migrating under the seal where the windshield met the seal, then going under the seal, under the windshield itself, and then coming out between the windshield and the seal on the interior. I have not found a leak from the sheetmetal side of the seal, even though it was not sealed either.

I tried to fix this two autumns ago, by using a "windshield silicone" that you can find with all the RTV tubes at the local autoparts store. This was a "flowable" silicone, that ought to flow into the leaky areas and seal it. I used this on the exterior along the seam where the windshield met the seal. I did not lift the seal and apply under the seal. This worked for a couple days, and overall reduced the volume of the leak, but was not successful.

Recently after posting up the windshield replacement PDF for another member, I decided to try to find the correct sealant and just apply the adhesive/sealant under the seal as noted in the FSM. I could not find the correct sealant in less than a case size online, so I looked for a Polyurethane adhesive locally. What I came up with was PL Polyurethane Roof and Flashing sealant in Black, from the paint supply area of Home Depot. It looked like it would do the job. You will also need cheap caulking gun.


First, I used a razor/scraper to try to get rid of the "flowable silicone" I had used before, then I used my finger to lift the seal and cleaned the seal and the windshield mating surfaces the best I could, using a dry cloth. When it was fairly clean, I used alcohol on a cloth. It actually felt like my seal may have been the original and had some adhesive residue on it from the original factory windshield. You can only get it so clean, so it would be better to have it done correctly with the install.

Next, I took some painters masking tape and put it on the winshield where it met the seal. I let it overlap the seal and then took a razor along the edge and peeled the tape off of the seal, this left me with a tape covering the edge of the windshield, to make it easier to keep the windshield clean.

After one last wipe of the seal/window mating surface with a clean cloth, I inserted the tip of the adhesive tube in the top center of the outside windshield/seal and started squeezing, I kept the tip"deep" and let the adhesive ooze out a bit, as I ran the adhesive around the windshield. I tried to make sure that there was a good mount of adhesive and no gaps. You can always cut/clean the extra adhesive, so be generous. When I finished, I gently pressed on the seal, just enough to make sure there was enough sealant to ooze out a bit, and make sure there were no areas where the seal was lifted up due to too much sealant.

It takes 7 days to fully cure, and you will smell it for about that long, it is strong at first, but not "deadly" as far as I can tell. After about 12 hours, I removed the tape, and did nothing else, but I did drive it with no issues. It will skin over after about 24 hours, and I think you would be OK in rain at that point, as it uses moisture to cure anyway, and I think the adhesive instructions makes mention of using it in wet locations.

I did this about a month ago, and it is bone dry inside. Hopefully, it will hold up in the long term, and I think it will. We have had some serious rain in the past month and it is always parked outside, so my expectations are high.

***Here is a link to my post with the FSM install document: Click here***
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Hi @firetruck41,

Thanks for sharing the info about this leak fix. It is such an annoying leak.... I'm currently mitigating the cause for both DS/PS front corner wet carpets and just finished going through the roof front drains and rocker pinch welds + plugs. The drain holes on the sunroof were a little clogged with some sort of dust/mud and leaf residue so I used the trimmer lines (roto rootter style) to unclog it and also swipped all the gunk from the area. Now water is flowing nicely all the way from the sunroof down to the rocker panels and floor. However, I have a questions about the windshield.

I replaced the aftermarket windshield that came with the truck with an OEM bronze glass 3 months ago. The leak was already happening before the windshield was replaced. The glass shop that performed the windshield replacement job does all the work for a local Lexus dealer but in my mind that doesn't mean anything. The guy confirmed that he knew how to install the windshield on a LX450 and would use only OEM parts. Long story short, after the windshield was installed, last week started raining around here and both DS and PS carpets (front corners) started getting very wet. I checked the wiring on the corners where we can access the drain tubes and it was a little wet. After some research I bumped on this thread which was great.

So, I don't see any signal of water coming through the new windshield seal. I checked the seal corners and all the way around the dashboard and nothing... all dry. Then I pulled the carpet under the glove box and behind the pedals on the driver side to see if there was any sign of water and it is also all dry. The only thing that comes to my mind is the "gutters" on the A pillars that could possibly be channeling the water from the sunroof to that corner. Maybe water is passing through some screws as stated on other posts here.

That said, I started looking at the windshield seals again. In your case, when you pulled the seal connected to the glass before your fix, would the seal come out easily? I tried doing that on mine to see if I can fit a caulking gun tip there but the seal is already water tight. Maybe my question is, how did you figure out that the windshield seal didn't have enough sealant? Just by pulling the rubber with your nail or with a plastic pry bar?
 
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@BlackMud I'm in the same boat as you where my windshield-to-gasket interface is sealed with adhesive, however, what's not sealed at all, is my gasket-to-body interface. I can easily lift up the gasket where it sits against the body of the vehicle.

Have people done the same masking tape and adhesive method to the body that they have to the windshield?
 

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