I just Cheapo'd the repair of the bottom of my windshield too. I figured maybe the windshield rust repair should not necessarily be in Cheap Trcks. It now stands on its own cheapness.
The top windshield repair was November 2012. The bottom repair was November 2014. Both still look good to date. [Feb. 2020.] [11/2020 Minor repair needed on top corners and lower section.]
Dicor 551LSB-1 Non-Sag Lap Sealant - Black is one possible caulk/sealant to use around the windshield. It is commonly found in RV stores.
I used white Dicor on my 2006 rear windows.
Caulk Around Rear Windows
https://sprinter-source.com/forums/showthread.php?p=511169#post511169
The top windshield repair was November 2012. The bottom repair was November 2014. Both still look good to date. [Feb. 2020.] [11/2020 Minor repair needed on top corners and lower section.]
Added:Windshield Leak Repair
Added:
Feb. 2020 - The windshield repair has not leaked to date. I am now beginning to notice some typical Arctic Whitewash small rust bubbles near the sealant beads. That will need some minor touch-up.
Let me say up front that many of my more fastidious friends here on the forum are going to be thinking up front "That goof should have repaired that sooner." Of course that is correct. I guess my role in our little forum community is to be that brother who puts things off a bit too long and then works to catch up. There are already enough people always doing the right thing, so I view my role as important in its own little way.
Anyway, I've been watching the rust along the top of the windshield getting bigger. The bottom was even worse. I did some repair to the bottom, but access to the top was going to be difficult, so I put it off. A while ago I noticed some staining inside on the upper front area of the headliner. What a surprise.
When I got up there to address the issue I found that the rust had continued down under the trim rubber. I call it trim rubber because it doesn't seal anything, it just conforms to the opening. Like any other cosmetic trim, its job is to look neat and pretty. It is not a "gasket" or "seal".
The other thing that the trim does is create a covered channel where dirt can get in, build up and then never dry out. I had trimmed off some of that rubber on the bottom when I repaired the lower section, but as it turns out, not enough. I should have been more aggressive with the amount of rubber I removed.
To access the rust channel I took a blade and trimmed off the entire 3/8" - 1/2" wide little strip. (A section of the removed strip is shown in the pictures.) Once I had a piece started it was easy to pull up on the loose end and follow along with the blade to cut it loose. That revealed mucky rusted areas which I couldn't properly get down into and grind out or clean to bare metal. I planned on only doing the top area, but as more poor condition was revealed I stripped the trim piece down both sides too.
Added:
Cutting the trim strip with a blade may not be necessary. It has been reported that the entire trim strip can just be pulled out using pliers.
Because the rest of the body is also deteriorating I will not go to the effort of removing my windshield for a repair. I decided my plan of attack would be to grind all that I could to provide a good clean painted edge along the entire window. I then wire brushed inside the groove as best I could. After that was complete I used rust combining primer followed by spray paint. I followed that with a bead of black polyurethane sealant.
My thoughts are:
The windshield is bedded into a polyurethane sealant.
The fancy trim piece catches muck and debris so it contributes to the deterioration.
I couldn't properly clean out the groove channel to bare metal for proper painting.
Even if I could, the rust likely penetrates under the sealant bedding already.
MB uses the rubber trim strip for ease of installation and looks, not for additional seal integrity.
An added bead of polyurethane sealed to the newly painted edge of the metal should shed and keep water out.
The bead of polyurethane will allow enough movement of the glass for temperature differences.
The water may still migrate into the original rubber trim seal "U" shaped glass holder, but it shouldn't get past the OEM sealant or the new bead. (That is a bit of a guess.)
Come spring I am going to do the same poly sealant treatment to the bottom area. That will require removing the hood completely for proper access. (I didn't remove the hood. See below.)
A more severe approach to the rubber trim material might be to completely remove the "U" channel piece and all. That will expose the glass edge of the windshield. It will then allow the added bead of new poly to bond to the glass and the newly repaired surrounding metal. That may actually provide a better water barrier and solution than leaving the "U" rubber intact.
That said, here's some pictures. Some may want to try this also. vic
What I used to access the top area of the windshield. I wasn't able to just lean a ladder up to get there.
The top area rust.
The cleaned and painted repaired groove. Notice how the groove shape lends itself to bead of sealant. The rubber piece is part of the strip I cut off to help show the size of it.
A view of the side area sealant bead. I almost didn't post pictures of my caulking job. It is not very pretty. I couldn't find my normal radius end caulk finishing tools so I just used a straight blade chisel. Not great looking results, but it should be sealed properly.
The top bead of sealant. The edges are irregular and looks like crap, but no more leaking.
Edit: As of today 2014/01/13, 2015/07/21 20160117, 20170731 the repairs are holding just fine.
Dicor 551LSB-1 Non-Sag Lap Sealant - Black is one possible caulk/sealant to use around the windshield. It is commonly found in RV stores.
I used white Dicor on my 2006 rear windows.
Caulk Around Rear Windows
https://sprinter-source.com/forums/showthread.php?p=511169#post511169
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