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3rd brake light leak fix

171K views 153 replies 91 participants last post by  bring10ants 
#1 ·
Just thought I'd post this up for what I did to solve my problem of the 3rd brake light leaking. I was getting water in both rear top corners of the cab where the headliner meets the plasic and rear window glass. What happens is the water leaks through the seal of the light, then makes it's way into the cab sheet metal, and runs to both corners due to the way the metal slopes. If you have water dripping from the top corners of the rear of the cab it is probably the 3rd brake light seal leaking. First thing I did was check to make sure the window seal also was not leaking, by pouring water in the open channel (once you remove the two screws holding on the light and pull the light off). There are weeps that let the water drain at the bottom of each corner of the window, my passenger side weep is wide open, the driver side weep is a little tighter (due to the window being installed slightly crooked), but it lets the water out fine. So anyway I then cleaned the sand/muck off where the light seals, and cleaned the old gasket off the light (very easy with flathead screwdriver, then again with adhesive remover). I then applied new thicker gasket (not a foam type like the original), I bought it at home depot, it is slightly wider, and about twice as think, but still very compressible. This is more rubber like (EPDM) than foam like, so should seal better. It doesn't turn sharp corners well, so I cut about half way through for the top two bends, and cut a separate strip for the bottom, this way the bottom corners are open and will let any water that may get in drain out. Pics....
 

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#4 ·
Hmmm....maybe a moderator can help me? I'd love to post the rest of these pictures as maybe they could help someone, but it won't let me attach anymore. It says "you have exceeded your quota"...?
 
#6 ·
Thanks redram, I'm going to give it one more shot...lol!

Here's a step by step on how I fixed my 3rd brake light leak issue...I had water coming in both corners of the rear of the cab, at the very corners of the headliner.

Remove screws from brake light, then remove lens (may have to pull pretty hard, I did). After lens is removed unclip wire harness (squeeze the clip on the connecter and it will release):


I tested to make sure the water that gets in between the front window "seal" and the rear actual window seal drains out the weeps (weeps are at bottom corners of the back glass):
Pouring water into the track:

Water coming out of the weeps:




Next clean the surface of the cab (mine was dirty with water/muck/sand that leaked in. Then you can scrape the old gasket off the light lens (comes off easy with a flat head screwdriver). After I got the majority of the gasket scraped off, I used some adhesive remover and scraped the film that was left behind off (this was a pain and a mess and probably not necessarily):





After the lens surface was clean I applied the new gasket. I bought this at home depot, I chose it because it is slightly wider than the original, and about twice as thick, but still very compressible. It is also more rubber like than foam like, so should seal better. It does not turn sharp corners well, so I cut about half way through at the top corners to turn the corners, but the outer edge is still seamless. I make the bottom a separate piece and left the bottom corners open so if any water gets in it can drain out:






Reinstall once done, it will not sit as tight as before (due to thicker gasket), but will seal. I'm guessing after a few months I will be able to tighten the screws another turn after the gasket gets "precompressed":



Did the hose test for above 5 minutes, not a drop in the cab. Still pending a heavy rain test. Will post back after it rains hard. This all took me about 30-45 minutes working slow. Hope this helps someone...
 
#132 ·
How do you get to the pictures?



Thanks redram, I'm going to give it one more shot...lol!

Here's a step by step on how I fixed my 3rd brake light leak issue...I had water coming in both corners of the rear of the cab, at the very corners of the headliner.

Remove screws from brake light, then remove lens (may have to pull pretty hard, I did). After lens is removed unclip wire harness (squeeze the clip on the connecter and it will release):


I tested to make sure the water that gets in between the front window "seal" and the rear actual window seal drains out the weeps (weeps are at bottom corners of the back glass):
Pouring water into the track:

Water coming out of the weeps:




Next clean the surface of the cab (mine was dirty with water/muck/sand that leaked in. Then you can scrape the old gasket off the light lens (comes off easy with a flat head screwdriver). After I got the majority of the gasket scraped off, I used some adhesive remover and scraped the film that was left behind off (this was a pain and a mess and probably not necessarily):





After the lens surface was clean I applied the new gasket. I bought this at home depot, I chose it because it is slightly wider than the original, and about twice as thick, but still very compressible. It is also more rubber like than foam like, so should seal better. It does not turn sharp corners well, so I cut about half way through at the top corners to turn the corners, but the outer edge is still seamless. I make the bottom a separate piece and left the bottom corners open so if any water gets in it can drain out:






Reinstall once done, it will not sit as tight as before (due to thicker gasket), but will seal. I'm guessing after a few months I will be able to tighten the screws another turn after the gasket gets "precompressed":



Did the hose test for above 5 minutes, not a drop in the cab. Still pending a heavy rain test. Will post back after it rains hard. This all took me about 30-45 minutes working slow. Hope this helps someone...
How do you get to the pictures? kellioed
 
#8 · (Edited)
THIS REALLY WORKS!
I have a 2006 Dodge Ram SLT Quad Cab.
I did the same thing snrusnak did, per his instructions in this thread.
Home Depot sells a Frost King door seal that is 5/16"x9/16" and is made of rubber, not the spongey material that is supplied by Dodge.
My factory gasket was in fairly good shape by appearance, but was failing due to the material being porous.
My 3rd light, now fits snugger and won't leak after 5 years from the assembly line.
I highly recommend repairing your 3rd light this way if you're having the same problem....
 
#10 ·
THIS REALLY WORKS!
I have a 2006 Dodge Ram SLT Quad Cab.
I did the same thing snrusnak did, per his instructions in this thread.
Home Depot sells a Frost King door seal that is 5/16"x9/16" and is made of rubber, not the spongey material that is supplied by Dodge.
My factory gasket was in fairly good shape by appearance, but was failing due to the material being porous.
My 3rd light, now fits snugger and won't leak after 5 years from the assembly line.
I highly recommend repairing your 3rd light this way if you're having the same problem....
Glad it helped you :) It's been a while now and still not a drop in my cab :)

Great post, gonna get some for my fix ASAP! Wife complains of the musty smell after the rain pours in!
Good luck (this is probably the best mod I've done lol as it keeps my truck from stinking!)
 
#15 ·
I had the dealerships body shop swap out gaskets on my 3rd brake light yesterday and the there's still a dam leak. I was going to do it myself, but they did the work for free.

They seemed real hesitant about tearing out the back window so I'm sure what to do. I've seen a couple of threads where guys are using the flowable silicone. Do you think this will solve my problem? I'm at a loss.
 
#17 ·
I had the dealerships body shop swap out gaskets on my 3rd brake light yesterday and the there's still a dam leak. I was going to do it myself, but they did the work for free.

They seemed real hesitant about tearing out the back window so I'm sure what to do. I've seen a couple of threads where guys are using the flowable silicone. Do you think this will solve my problem? I'm at a loss.
Just because they replaced the gasket doesn't mean it'd fix the leak. The gaskets are a faulty design. I'd recommend spending $10 and 30 minutes and follow my write up and try that out before doing anything with the window. It's more than likely the light.
 
#19 ·
The morning after taking delivery of my '11 I found buckets of water inside after an all night rainfall. Took it back, and eventually dealer ended up taking the third light out of another truck on the lot to get me rolling (I bought out of town and couldn't wait for parts). Have been in torrential rains since, and it hasn't leaked a drop.
My '10 has never leaked a drop, but my '06 started leaking after a couple years.
Seems like a weak design area...if anyone sees water inside the cab this is the first place I'd look.
 
#22 ·
^wow yours was really bad! You get it fixed?
I am going to do it later tonight. This is the first time I have ever noticed it.

I am not sure how I am going to fix it yet. I just realized I posted this in the OP's mod thread (which is a great idea BTW) instead of the leak thread I found first. Thanks to your guys' help I don't have to rip the headliner down looking for the leak. :smileup:
 
#24 ·
Thanks Sean,

I'm sorry I called it a mod thread. I just figured since you went against the grain so to speak with the weatherstrip it was a "mod". Anyway, I decided to use strip caulk instead. I water tested it for the last 3 hours without a drop. Yours would be easier to replace bulbs, but I can deal with a semi removable gasket as it is what I had laying around the shop. Thanks for the ideas!







 
#30 ·
lol. Sort of like duct tape! I watched a mythbusters episode last night all about duct tape, and they made a duct tape canoe and used it in the ocean for like 8 hours without a leak. Took them like 6 hours and dozens of rolls they said lol.
 
#31 ·
Has this worked to fix leak from the DRIVERS SIDE DOOR GRIP (located on the interior of the driver side column) aka handle you grab while getting in?

My truck leaks after a hard rain from that handle. 3rd gen, no sunroof. I have not had any leak around the ceiling or in the back, just at the drivers door grip, through the bottom hole.

Thanks!
 
#32 ·
I'm not sure. I suppose it's possible for the water to travel to the front of the cab. I'd suspect this would only happen if parking on a hill with the rear of the truck elevated, though.

Might be the door seal, rain channels, windshield, or sunroof also, in that area.
 
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