Fixed leaking rear door vapor barriers (pics) - The Unofficial BMW M5 Messageboard (m5board.com)

timmay77 · 30th August 2009, 04:11

Thanks to Lunker325 (Brian) for info on how to do this, I fixed my rear doors from the leaking water horror that some M5's suffer from. Very easy DIY. Mx5 is coming over next week to do some work on his car and mentioned he wanted to do this repair so I thought I would go ahead and get my car done so it will be easy to do his. We will be working against the clock on his car, so I wanted to do a trial run.

Remove door panel (One screw on door handle, the rest is just pop locks securing the door. Take out the window switch and the flood light and unplug them.

Clean up area around old seal

Use some silicone to create a new seal (I used 732)

Tape up seal until it cures

Let car air out (I hate the smell of silicone)

Re-install door panel

Pics....

Visible water damage

Old rubber seal

I love blue tape

I know you are digging the power wheels in the background.....

Hdhntr23 · 30th August 2009, 04:17

Soon VERY soon.

sidneyj · 30th August 2009, 15:37

Not sure what silicone 732 is and why you have all that blue tape holding the barrier on? What you need to do is remove the old barrier and remove all the original black 3M sealer which is extremely tacky and somewhat difficult to remove. However, once you discover how to remove it it gets easier. Once you have like a golf ball sized chunk rolled up you actually use that as a magnet to get the rest of the stuff off by "blotching" the old seal. Again, it's difficult and you need to repeatedly go over and over the old seal until it lifts off. Once you have the old seal off and everything cleaned up just place a new seal along the old path, on the door, not the barrier, as you will see where the old seal was as it contours along the door. You don't need a new barrier unless it has a tear or hole in it. Press every square inch of the barrier back on the new sealent and you don't need tape to hold it and it doesn't need to cure. This "732" stuff that needs to be cured, not sure you should use that. This 3M stuff, I forget the product # can be had at the dealer, or, I did see the EXACT same stuff at Advance Auto type auto parts stores. If anyone wants the product # I can look in the garage.

Hdhntr23 · 30th August 2009, 15:59

Quote:

Originally Posted by sidneyj

Not sure what silicone 732 is and why you have all that blue tape holding the barrier on? What you need to do is remove the old barrier and remove all the original black 3M sealer which is extremely tacky and somewhat difficult to remove. However, once you discover how to remove it it gets easier. Once you have like a golf ball sized chunk rolled up you actually use that as a magnet to get the rest of the stuff off by "blotching" the old seal. Again, it's difficult and you need to repeatedly go over and over the old seal until it lifts off. Once you have the old seal off and everything cleaned up just pace a new seal along the old path, on the door, not the barrier, as you will see where the old seal was as it contours along the door. You don't need a new barrier unless it has a tear or hole in it. Press every square inch of the barrier back on the new sealent and you don't need tape to hold it and it doesn't need to cure. This "732" stuff that needs to be cured, not sure you should use that. This 3M stuff, I forget the product # can be had at the dealer, or, I did see the EXACT same stuff at Advance Auto type auto parts stores. If anyone wants the product # I can look in the garage.

2 things, first if Im reading your post correctly youre saying that you should use the 3M stuff instead of the silicon and its the same exact stuff they used to build the car. If thats correct, then isnt the same thing going to happen again?

Second, silicon is waterproof and Im pretty sure itll last ages longer than the double sided tape that youre referring to.

To each his own but when I do this and its going to be soon because I just found my back foot wells sopping wet, I want a permanent fix so I dont mind having to let it cure nor do I mind using the painters tape to hold it in place until its done so.

I may have read your post wrong. I appreciate you posting an alternative approach but to me I want something thats gonna last longer than it did from the factory. Silicon I know for sure will do that.

sidneyj · 30th August 2009, 16:15

Quote:

Originally Posted by Hdhntr23

2 things, first if Im reading your post correctly youre saying that you should use the 3M stuff instead of the silicon and its the same exact stuff they used to build the car. If thats correct, then isnt the same thing going to happen again?

Second, silicon is waterproof and Im pretty sure itll last ages longer than the double sided tape that youre referring to.

To each his own but when I do this and its going to be soon because I just found my back foot wells sopping wet, I want a permanent fix so I dont mind having to let it cure nor do I mind using the painters tape to hold it in place until its done so.

I may have read your post wrong. I appreciate you posting an alternative approach but to me I want something thats gonna last longer than it did from the factory. Silicon I know for sure will do that.

I think you read at least some of it wrong. I didn't mention anything about using double sided tape. I indicated no tape is needed to hold the barrier on while it's curing because using the 3M stuff requires no curing.Yes each into his own here but I think where the problem comes in here with this failure on the barrier is from previous work someone has performed while having the door panel off and not correctly re-installing the barrier. The 3M factory stuff is plyable and meant to be removed and re-used if needed. Example: if you need to remove the door panel for some reason and work behind the barrier you can carefully, slowly pull the barrier away from the door and place it back without issue. My guess is using the 732 stuff that needs curing would require a total re-do if removed? The factory stuff does not fail if it was installed correctly and it will never break down for no reason. I had an issue with my 2003 right rear door leaking and discovered the dealer never installed it back thoroughly. If done correctly and one takes there time to install it completely then this 3M product will not fail. Also, if you have "sopping" wet footwells I would remove or at least lift the carpet up back there where it was wet and let it dry out and maybe even spray something to kill any potential mold that may have grown under the carpet. Maybe I'm just being anal but thinking logically of at least what I would do.

Flybot · 30th August 2009, 17:00

That correct 3M product number would be handy.

Tyrone D. · 30th August 2009, 17:59

Quote:

Originally Posted by Flybot

That correct 3M product number would be handy.

3M Automotive (MMM8610) 3M„ Window-Weld„ Round Ribbon Sealer, 1/4" x 15' - MMM8610

BAD TA WS6 · 30th August 2009, 18:00

BMW has their own Buytl tape which is the correct way to repair this. Remove the door panel, remove the vapor barrier (do not tear/rip it). It's important to remove all the old butyltape next. Then lay a frash bead of ribbon sealer/tape around the area. You can use a heat gun over vapor barrier quickly, to get the tape nice and sticky. Re-install the door panel and you're done.

Silicone is going to be a major PITA to clean up next go around. Definately would not use this method.

Normally the factory tape fails, because whoever was last in there replacing a window regulator, etc. Didn't take the time to replace the tape. They just tried to reuse it, and as you can see, it never works that way. Not unless you heat it with a heat gun, and try and get it tacky to re-use it.

Lunker325 · 30th August 2009, 18:20

There are several ways to fix this. On my old 540 I used just silcone sealant, plenty of it, and it held up for years until I sold the car. On this car, I used the window weld stuff, AND silcone sealant around the outside edges just to make sure no water would get onto my illuminated door sills, or into the car.

timmay77 · 30th August 2009, 21:25

I personally did not reuse the original stuff because in my eyes it will just fail again. I have every record from my car since it's in-service date, and no one has ever had that door apart. The previous owner was not a DIY guy, EVERYTHING was done att the dealership. 732 is just Industrial Loc Tite silicone that we use at work to fix just about anything that needs to be repaired in a water tight situation. IF I do ever need to get inside that door panel I will cross that bridge when I come to it. I would much rather have to deal with a PIA door repair if a regulator fails than have to worry about the original sealer failing again causing my door to leak again. I can pretty much garuantee this stuff will not leak.

Sometimes OEM isn't the best route to go.

But again, to each his own.....