Door waterproof membrane

[Bumpa]

The wet floor saga continues! Since the floor is dripping wet both in front and behind the cross member that divides it, it seems reasonable to me that rain coming from behind the door trim panel is the most likely source. So I took the passenger door panel off and look what I found. Not only is there all that duct tape, but I see the membrane is cracked quite badly in several places. Someone has obviously been here before trying to fix the same problem.

It started getting dark so further investigation was stalled. How is the membrane fixed to the door? Is it glued on? Can I buy a new one? What should I do to keep the water inside the door from where it can escape through the drain holes?

 

[Davyhoogy]

I doubt that is the source of wet floor. It' more likely a clogged drain hole in the A pillar or a seen better days door seal at the bottom.
I'e recently purchased a role of soundproofing and I'm going to cut them to shape and fit them there, which I'm hoping makes the cabin a bit quieter. So that is one option for you.
I'e never actually seen one of those that nice before haha mine was like tracing paper

 

[jonco]

............. How is the membrane fixed to the door? Is it glued on?

Silicon sealant -see pic

 

[Brian4]

They are fixed on with butyl sealant but thick layer of Black Silicone looks similar.

Ours was leaking through a small area of the sealant where it wasn't fixed properly and when we sprayed the hose on the window the water could be seen dripping from behind the door cards. strange but true.

Our carpets were wet through and caused our DSC lights to be on but since sealing the membrane no leaks and dry carpet. Ultimately I guess the window seals have lost flexibility .

 

[Bumpa]

Yes it has been DSC lights that prompted this saga. The sensors on the floor were swimming in a lake. So it's gratifying Brian that sealing the door membrane fixed your leak. You say the window seals have lost flexibility, but in fact it is virtually impossible to prevent water getting inside the door even from new. That's why all car doors have drain holes.

 

[Brian4]

Yes it has been DSC lights that prompted this saga. The sensors on the floor were swimming in a lake. So it's gratifying Brian that sealing the door membrane fixed your leak. You say the window seals have lost flexibility, but in fact it is virtually impossible to prevent water getting inside the door even from new. That's why all car doors have drain holes.

I was about to say that and is surprising how much water runs out of them. I guess the drips off the bottom of the window glass supprt and a few drips find their way onto the winder linkage and splash onto the membrane and eventually find the weak spot in the membrane.

This is where the gap was in ours so some silicone has cured it.

 

[Steve Medlock]

Anyone Waxoiled their door bottoms? I'm just fitting a new lock actuator and its slightly damp in the bottom of the door.

 

[Dino D]

....slightly damp in the bottom...

Sounds like you need pampers not waxyoil

 

[Steve Medlock]

Sounds like you need pampers not waxyoil

Wait until you get to my age.....

 

[jonco]

Anyone Waxoiled their door bottoms? I'm just fitting a new lock actuator and its slightly damp in the bottom of the door.

Yes - just make sure drain points are still clear afterwards.

 

[Clockwatcher]

I am sorting out the doors on our Z3. Do not understimate the issues a torn or badly sealed membrane can cause when it rains, especially in driving rain. Pouring water along the bottom window seal should show if you have issues with your membrane(s) or blocked door drains. Open your door first and pour from the outside!

Replacement membranes are roughly £70 from Sopers (Lincoln) : Part numbers are
LHS: 5148 8410037
RHS: 5148 8410037

Source: https://www.realoem.com/bmw/enUS/showparts?id=CH32-EUR-09-1999-Z3-BMW-Z3_28&diagId=51_2351 (Z3, 1999, 2.8i)

The old ones are held on by a butyl mastic with a thin wire/cord inside which helps remove it from the door when you pull the wire/cord. Makes sure the surfaces are clean before you reseal. I doubled/folded the tape I used over to make a thicker bead as it was "flat" buytl tape. You can buy tape that is more of a bead/rope shape though if you search online.

Buytl tape: https://www.amazon.co.uk/s?k=canopus+butyl&crid=X59ORPGTRDF7&sprefix=canopus+butyl+,aps,70&ref=nb_sb_noss_2

If your door card is missing any clips make sure you seal the corresponding hole in the door before you refit your door card.

Small tears in the membrane can be glued together using Stormsure when the membrane is dry. Awesome glue. It is messy stuff and has a short shelf life though! https://www.amazon.co.uk/gp/product/B00IHVJP6E/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

I also used Stormsure on the bungs at the top of the A piller, and as it also comes in black it looks good.

CW

 

[jaguartvr]

Check the tray where the hood hinges, the start of the roof when the door is open.
Watr\]er from the whole roof drains into this tray and the drains are very prone to bolocking, if they are blocked the water will drain into the car.
If you pour some water into the trays on both sides you should see it escaping in the join between the rear wing and the top of the sill, it is easily seen. If you can't see it it is draining into the car due to a blockage.
The drain hole is quite hard to see but you need to find it and rod it out with a piece of wire.

 

[Duncodin]

Pour some water on the outside of the door window. The water does find its way onto the inside of the plastic sheet. If there's a leak you'll see it dripping down the inside of the sheet. If the sticky stuff isn't good along the bottom of the door it will drip down onto the carpet.

But my biggest problem, as I've said before, was the drains tube from the area by the windscreen wipers and heater air intake. At the base of the windscreen there's a wide plastic strip that's attached with plastic rivets. If you take that out you'll see all the muck under there and also see these drain holes I'm talking about

See number 5 on this diagram. There's two of them. One either side of the transmission tunnel.

RealOEM.com - Online BMW Parts Catalog

BMW parts Z3 E36 Z3 1.9 Splash wall parts

www.realoem.com

They have a kind of closed flap that is supposed to let water out but not in. All the muck and leaves that land at the base of the windscreen finds its way into that trough and down into those tubes and can't get past that flat end so the channels get blocked and LOTS of the water running down the front of the windscreen gets into the car via the heater intake.

 

[Duncodin]

Check the tray where the hood hinges, the start of the roof when the door is open.
Watr\]er from the whole roof drains into this tray and the drains are very prone to bolocking, if they are blocked the water will drain into the car.
If you pour some water into the trays on both sides you should see it escaping in the join between the rear wing and the top of the sill, it is easily seen. If you can't see it it is draining into the car due to a blockage.
The drain hole is quite hard to see but you need to find it and rod it out with a piece of wire.

Yep. This is another good one. Water in the channel around the front of the boot lid runs forward alongside the rear wing and is supposed to end up in those channels that JagTVR is talking about. In my case the sticky stuff sealing the back bow of the soft top wasn't intact and water seep through under the bow and onto the shelf behind the seats and run down behind the seats.

EDIT. I take back what I said here. I've now got my wings off and looking at that area, front corners of boot lid, I can't see how water gets through there. I'm sure I pored green water on there and got green water on the shelf by the shocks but I really can't see how. So maybe I just spilled it without noticing.

 

[Bigfella70]

Pour some water on the outside of the door window. The water does find its way onto the inside of the plastic sheet. If there's a leak you'll see it dripping down the inside of the sheet. If the sticky stuff isn't good along the bottom of the door it will drip down onto the carpet.

But my biggest problem, as I've said before, was the drains tube from the area by the windscreen wipers and heater air intake. At the base of the windscreen there's a wide plastic strip that's attached with plastic rivets. If you take that out you'll see all the muck under there and also see these drain holes I'm talking about

See number 5 on this diagram. There's two of them. One either side of the transmission tunnel.

RealOEM.com - Online BMW Parts Catalog

BMW parts Z3 E36 Z3 1.9 Splash wall parts

www.realoem.com

They have a kind of closed flap that is supposed to let water out but not in. All the muck and leaves that land at the base of the windscreen finds its way into that trough and down into those tubes and can't get past that flat end so the channels get blocked and LOTS of the water running down the front of the windscreen gets into the car via the heater intake.

Just looking at doing this job soon, whats the best way you’ve found of clearing the drain tubes please ? Can they be accessed from underneath as well as via the plenum above…

 

[jaguartvr]

Strimmer cord pushed down the drain hole. When done pour some water ov er the hood just above the rear wing and you should see water exit between the join at the front lower edge of the rear wing and sill.

 

[Duncodin]

The plastic panel that lays the full width of the car at the base of the windscreen. Once that's off you have easy access to the drain tubes. It's just like a rubber grommet tube kind of thing that you can take out and clean.

I haven't looked but I wonder if they're visible/accessible from below the car either side of the rear of the engine/bell housing.

 

[John_B]

The plastic panel that lays the full width of the car at the base of the windscreen. Once that's off you have easy access to the drain tubes. It's just like a rubber grommet tube kind of thing that you can take out and clean.

I haven't looked but I wonder if they're visible/accessible from below the car either side of the rear of the engine/bell housing.

Deleted, sorry, misread your comment

 

[jaguartvr]

Not visible underneath as they terminate behind the front of the rear wing just above the sill, this is why the water drains between the gap of the 2 panels.

 

[Duncodin]

Not visible underneath as they terminate behind the front of the rear wing just above the sill, this is why the water drains between the gap of the 2 panels.

We're talking about different things

Or I am.

Sorry. I thought we were still talking about the drain tubes in the bulk head either side of the heater intake.