Vapor Barrier - What's the specific/ideal adhesive for repair?

[keitho64]

I am not sure of the answer about the front doors but I would assume it would end up in the front.

Here is what I did on my rear doors. I added a piece of 8mil plastic and tucked it in under the bottom of the door to divert water away and hopefully end up exiting out the drian holes. Time will tell if this actually worked.

[champaign777]

Hey guys,

Bringing on old thread back. Question re FRONT vs REAR doors.

I understand that when the REAR Door Vapor Barrier seal is bad, water gets into Rear Passenger floorboard.

The question is: when FRONT Door Vapor Barrier seal is bad, does water get in the front floorboard?

looks like the problem is related to REAR only

have REAR done but never front , no issues for front

[rf900rkw]

Specificly the left rear door. Apparently in that door the water can run in past the window seal, get across and squeeze between the vapor barrier and the door frame, trickle down from behind the door panel/trim, then flow UPWARDS between the inner panel and last weather seal, and on into the floorboard.

[champaign777]

after only 2 years the LEFT SITE REAR door repaired by 3M Windo-Weld Ribbon Sealer starts to leak again
another door has no leak



so now i need REDO it again, this time with a new Vapor Barrier ( 30$ from dealer )



What a piece of German crap

watch your REAR DOORS even you think you already fixed it !!

[Doru]

Hey guys,

Bringing on old thread back. Question re FRONT vs REAR doors.

I understand that when the REAR Door Vapor Barrier seal is bad, water gets into Rear Passenger floorboard.

The question is: when FRONT Door Vapor Barrier seal is bad, does water get in the front floorboard?

Did the front door actuator, and the vapor barrier is toast. have to re-do it. And I have the answer: Yes, water gets inside if the front seal is gone. The result is a succession of nasty electrical gremlins. Ask me how i know.
I am contemplating 3M 8609. Any word of wisdom? Anyone tried it?

[rjhagan]

Great info and thanks for finally getting a picture loaded! As someone asked earlier on, what's the best way to dry the darn thing out? I've got about an inch of water (heavy rains last couple of days) and I'm pretty sure It'll have to be vacuumed out. How hard it it to pull the carpet? Thinking this is part of my electrical issue as well. All the grounds seem to be in good shape yet the turn signals continue to flash quickly and I keep getting the "check brake lights" error even though all the bulbs are working..

[pamp]

Thing is, under the passenger seat is a fuse box. Fuse-able links. After years of leaks you will have nothing but electrical mayhem. "Check brake lights" is the first indication. On my '02 this box was a corroded mess...the car finally gave it up...alarms doors, you name it. So we pulled the seat and box sealed a new unit...added some drain holes...hard soldered all new wiring needed. For sure a bad design by BMW! Now the dash is totally functional, as before there were bad digits. Like having a new car! Sealing the rear passenger door was the EZ part!

[lesguy]

Couple of key things: The white plastic door panel clips must ALL be in perfect condition. They help seal those holes to prevent water from seeping in through those holes. Also, for me, using a hair dryer on high to heat up the metal part of the door and soften up the 3M window weld as I went along, was key. At the bottom I ended up putting down two parallell layers of the window weld to ensure the barrier stuck well. It's key to really press down hard on the vapor barrier with a roller of some sort to make sure it's a very, very tight seal. Then again, go over it with a hair dryer or heat gun while pressing to triple ensure its sticking tight at all places along the bottom and side edges.

[Da Beemers]

The mold release agent on a new foam barrier probably should be washed off with soap and water. I have a feeling this may have been the cause of this problem all along. Even when just reusing the original barrier, a good wash of the mating surface may help ensure a longlasting repair. The mold release agent used on these foams is made to prevent sticking to the mold, and if not washed off...

[lesguy]

Couple of key things: The white plastic door panel clips must ALL be in perfect condition. They help seal those holes to prevent water from seeping in through those holes. Also, for me, using a hair dryer on high to heat up the metal part of the door and soften up the 3M window weld as I went along, was key. At the bottom I ended up putting down two parallell layers of the window weld to ensure the barrier stuck well. It's key to really press down hard on the vapor barrier with a roller of some sort to make sure it's a very, very tight seal. Then again, go over it with a hair dryer or heat gun while pressing to triple ensure its sticking tight at all places along the bottom and side edges.

Followup on this: Noticed that the plastic part of the door sills(rear) would have a few drops of water on them after rain or a wash and I'd see a few drops of water on the underside of the bottom of the door card. Also, I'd remove the light on the bottom of the door card, place my finger in and around that area, and feel where water was leaking once again past the vapor barrier.

So, back to start. Removed the door card and ran some tests. Opened the door and poured water along the outside of the glass especially down where the rear 1/4 glass meets the main glass. Looked inside and noticed a few drops of water seeping outside the vapor barrier from what appeared to still be a good sealed vapor barrier. But obviously not. Upon closer inspection it turned out that adding too MUCH butyl actually caused a problem, because the butly was going up and over the "lip" of the door frame (the first pic in post #79 of this thread gives an almost exact location of where Im referring to), causing the butly to actually enhance leakage over and down between the vapor barrier and the door. I heated the butly with an hair dryer in that location, lifted up the vapor barrier some, scraped away the excess butyl that had gone up and over the lip of that portion of the skin of the door, reheated again, re-seated the vapor barrier, pressed FIRMLY with the round end of my screwdriver handle all along that location, and for extra measure, placed a few strips of duct tape around the edges of the vapor barrier to try to keep the barrier firmly pressed down against the door metal. Repeated my test of pouring water down the outside of the glass, and while a bit of water trickled out of the holes where the door panel clips go, no actual drips coming from underneath the vapor barrier. I had a bunch of spare clips, so for my next test I actually pressed door panel clips into the holes, retested, and no water leaked out at all except from the appropriate two drain holes underneath the door. The key is really to do the water test before replacing the actual door panel, because all it takes is one small section of the butyl/vapor barrier between the bottom portion of the 11 oclock and 2 oclock positions, to not be firmly in place to allow drops of water to enter the backside of your door panel and drip to the bottom of your door panel where your door panel will begin to soften/deteriorate/rot, and water simultaneously enters your cabin/carpet in the back.

Does anyone know WHY the water leak holes are located at the base of the window gasket on the door by the windows? Seems like sealing these up with tiny dabs of butyl would definitely solve the leak issue with no negative affects otherwise as the water would just run down the outside of the car.

[evomel]

after paying 2 professionals to seal my leaky barriers a few years back I took control and for the second and final time resealing them myself I used 3M RTV sealer and all my worries went away!

[lesguy]

Only concern there is being able to get in to do a window regulator repair without destroying the vapor barrier.

If I leak again I'm going to go the route above in this thread and install the plastic sheeting method

[evomel]

Heat gun or dryer will soften up the rtv for guy to make any possible future repairs

[1gr8e39]

I had my Vapor Barriers all replaced by my local BMW indy, and the one thing they made me sure to do was hang a bag called "damp Rid" that can be purchased at any hardware store. I believe its called Desiccant bags generically. Definitely is a major help after any vapor barrier change.

[Flounderasu]

I used 3M RTV sealer and all my worries went away!

+1 - available at NAPA - something like $20 for the butyl roll.

Only concern there is being able to get in to do a window regulator repair without destroying the vapor barrier.

Heat gun or dryer will soften up the rtv for guy to make any possible future repairs

+1 heat it up with a hair dryer - heat gun might be a bit too hot if you're not careful. I just leave the door open in direct sunlight for about 5 min...just be careful when you pull it; pull slowly and you'll be fine.

[Jarhed]

Butyl sealant. Comes in a roll with a bead of black butyl. It's the original stuff if I'm not mistaken. About $19 at Advanced Auto.

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[lesguy]

definitely knew that Butly needs to be heated with the hairdryer, but wasnt aware that heating RTV with a hairdryer would allow it to come off easy, especially from the backside of the foam vapor barrier. Learned something

[evomel]

The BUTLY doesn't work very well.. I have done it twice, and 2 pro's have done it twice.... doesn't work well,,, best was with RTV sealer for barrier will post a pic ,, seals the barrier perfectly NO LEAKS EVER.......

- - - Updated - - -

This is the BEST sealer!!!! Like I said twice I used the butly as well as two pros and all 4 times leaks!!! I used this once worry free now goes on wet , let it sit a bit and then lay down the barrier back on and roll the edges well untill it's down firmly

[BimmrMeUpSnotty]

The 3m Butyl rubber works great, one just needs to use it properly. First, you have to clean out most of the old stuff, then you have to clean the metal surface real well with some alcohol. The stuff left over on the barrier, try to clean it off as best you can, it does not have to be perfect, if it has dust, soil, or dirt, then you have to clean that portion off real well. Lay in the rubber strip, hit it with a torch or heat gun, this gets it real soft and gooey, splat the barrier on, apply good pressure all the way around. The next time your regulators go bad, you just peel it loose, those who used silicone sealant will then know the errors of their ways....

[lesguy]

The butyl seems to stick to the actual metal of the door quite well in my experience. I've even had success with new butyl sticking well ontop of old butyl. It's the butyl pulling away from the backside of the vapor barrier, particularly on that lower rear corner like shown in post #79 thats the issue. Exact same place. Hopefully the duct tape that I applied holds tight to keep it from pulling away.

[lesguy]

Update. So after some fairly thorough testing, results so far are so good. The duct tape is holding well and keeping the barrier from pulling away from the butyl, but I think the biggest factor was using tiny dabs of butyl to seal the four common small gaps in rubber on the outside of the door along the rubber seals by the glass. I have a feeling that when these cars were new, those gaps werent as large, thus, large amounts of water werent pouring down into the door forcing the vapor barrier to "work" as hard at keeping streams of water from flowing into the car

[sealbeach740]

I agree with evomel (above).

I tried first just patching the leaky area with 3M Butyl WindoWeld. Held for a short time.
After that rear corner started leaking again, I took the vapor barrier all the way off, cleaned off ALL the old butyl (& I mean ALL of it) & re-applied it around the whole vapor barrier area. This held longer, but after a while, it started leaking again.

So, this time I went ahead & purchased 2 new (silver colored) rear vapor barriers for each of the 2 rear doors, once again cleaned off ALL the old butyl sealer, & this time I used Dow Corning 732 RTV Sealant. Comes in a toothpaste type tube. Spreads out & applies easily.
Once it was applied around the door frame, I used painter's tape to hold the vapor barrier down overnight while it set up & dried.

Next day I pulled the painter's tape off & put the door cards back on & haven't had any water leaks since.
Just because I was starting to have door lock issues, I replaced both rear door locks before I did the vapor barrier re-do.

I'm hoping I won't have to go back inside those rear door cards again. So far so good.

[mxchris727]

Would replacing the door/window seal fix the problem?

I would worry about rust forming inside of the door.

[lesguy]

After lots and lots of reading, and having each rear door panel off about 4 times (each) at this point, I'm leaning towards that being a huge key in the overall equation for the true solution. (replacing that aged rubber seal at the base of the rear door window). Because sealing up the gaps in the seal (4 of the gaps on each rear door window seal) definitely and drastically reduces the amount of water that the vapor barrier has to deal with. My theory is that if one were to replace those seals with brand new ones? There would be minimal, if any gap, at those points and as such, the vapor barriers would not be subjected to so nearly as much water

[Jarhed]

The BUTLY doesn't work very well.. I have done it twice, and 2 pro's have done it twice.... doesn't work well,,, best was with RTV sealer for barrier will post a pic ,, seals the barrier perfectly NO LEAKS EVER.......

- - - Updated - - -

This is the BEST sealer!!!! Like I said twice I used the butly as well as two pros and all 4 times leaks!!! I used this once worry free now goes on wet , let it sit a bit and then lay down the barrier back on and roll the edges well untill it's down firmly

I have never heard that before. Not sure who your "two pros" are, but I've used Butyl for car projects for at least 15 years. I've never had an issue with it. My only issue with it is that it's so freakin messy, especially if you aren't careful (in a rush). I've sealed up two E39's, one E32, and an E60 with this stuff and haven't heard a peep since.

- - - Updated - - -

The 3m Butyl rubber works great, one just needs to use it properly. First, you have to clean out most of the old stuff, then you have to clean the metal surface real well with some alcohol. The stuff left over on the barrier, try to clean it off as best you can, it does not have to be perfect, if it has dust, soil, or dirt, then you have to clean that portion off real well. Lay in the rubber strip, hit it with a torch or heat gun, this gets it real soft and gooey, splat the barrier on, apply good pressure all the way around. The next time your regulators go bad, you just peel it loose, those who used silicone sealant will then know the errors of their ways....

This ^^^^

I didn't heat mine, but if you don't clean the door (I even cleaned the barrier with mild soap and water), it will be like putting cellophane tape on a dirty driveway.