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Water where it ain't supposed to be

Z3 Roadster (E36/7) 
6K views 18 replies 8 participants last post by  alcofribas 
#1 ·
A few days ago we had a very heavy rain here in Western NC. Afterwards, I reached into my trunk to retrieve an umbrella... and was greeted by a minor flood, including a couple of inches of water in the battery compartment. Turns out my brand new top was installed with a tiny flaw -- a kink in the butyl rubber tape sealing the top from the rear of the car, allowing a substantial stream of water into a normally protected area. The car is back at the auto upholstery installer; the top will soon be detached and correctly re-installed. Apparently no one did enough of a test for proper sealing the first time before handing the car off to me. Dry car, please! :mad:
 
#11 ·
Water where it ain't spozed to be, part deux



Now that my 2001 Z3 is back at the top installers for the 3rd time because of the leak into the trunk area, my garage people purchased a new sealing frame, and will observe the top being installed with the new piece (which runs about $150).

There was also the thought that the sealing tape runs across a joint, which may have been implicated in the leak. (Funny, because it never leaked during the two months I owned the car before the top needed replacement.)

The mechanics I'm working with pointed out that a few of the tools in the tool case showed signs of rust (especially the jack), which may indicate previous water problems.
 
#6 · (Edited)
I had almost the same issue. I purchased the car and found my trunk flooded after the first rain. The previous owner said he had recently had it repaired at a local upholstery shop. I called the upholstery shop and they said they would honor their work. I dropped it off the next morning. When I returned to pick it up that evening, the techs were checking it for leaks. To my dismay, it still leaked. They said I would have to drop it back off so they could try to figure out the problem. I took it home, disassembled the top myself and couldn***8217;t believe what I found. They had not used any butyl tape at all. They simply filled the gaps with at least three different compounds ranging from clear silicone bathroom caulk to black RTV. Needless to say, I didn***8217;t take it back. The sealing frame was broken in two but repairable. I cleaned out the mess and used some high density weather stripping ($3) in place of the butyl tape. After putting all back together, it hasn***8217;t leaked since and that was over a year ago. Here are some before and after pictures of their handy work***8230; Make sure you ask questions and if you can, try to be there when they are doing the work.
 

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#7 ·
I took it home, disassembled the top myself and couldn't believe what I found. They had not used any butyl tape at all. They simply filled the gaps with at least three different compounds ranging from clear silicone bathroom caulk to black RTV. Needless to say, I didn't take it back.
Wow! What a hack job. FWIW, you can get great prices on butyl sealing tape from RV suppliers.
 
#8 · (Edited)
I supposed that if had known what I was getting into, I would have ordered it and had it on hand. As it happened, I just needed to get the thing back together before dinner was ready. I was already in the dog house for buying the car. If it ever leaks again, which I don't think it will, I'll put the butyl tape in. I forgot to mention that the upholstery shop was going to "give me a break" on the labor the next time I brought it in. The nerve...
 
#9 ·
You just cleaned it up and re-assembled it with no butyl tape, and it doesn't leak?

I was in the same situation where a previous owner had the top replaced and it leaked. I removed the top and sealing frame it it looked like yours, without the silicone stuff. My sealing frame was broken into three pieces. I cleaned it up (a nasty job), installed a new sealing frame with new butyl tape, and it still leaks a little. I now have to start over.
 
#10 ·
Backlane,
Yup. No leaks. The high density weather strip did the trick. I think the most important part of the installation was remembering to tighten the bolts starting from the middle toward the outside. I was able to repair the broken sealing frame with some aluminum tape. This might be a stupid question, but did you put the butyl tape on both sides of the sealing frame? I hope I didn't just insult you but I had to ask. If your leak is down by battery compartment, it is more than likely your brake lights leaking. I had to fix those too (pictured). Poor design causes the fixture to heat up and crack in the worst spot. Right were all of the water coming off of the hood seem flows across. Good luck with your repair.
 

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#12 ·
There is no "joint" on the sealing frame. There are also no "joints" on the car bulkhead or top frame that the sealing frame mounts to. All three surfaces are smooth. Notice the pictures above. There is only one reason for a leak; inproper installation. I wouldn't tell them that, but insist on them fixing the problem if it continues to leak.
 
#15 ·
Z3 Roadster - dry interior and trunk at last



A big thank you to everyone who commented and made suggestions in this water-in-the-wrong-place thread. My Z3's top is now installed and water-tight. We had the installer put in a new sealing frame, plus inspect the various panels that are sealed with at-the-factory material. My indy German car garage went considerably beyond the call of duty to pursue the problem and solve it. I'm going to dip my rusty tools and jack into a diluted solution of muriatic (hydrochloric) acid, then neutralize it and give them a light coat of paint. Grease the jack screw, of course. Then I can proceed to install the seat shims and replace the sensors under the passenger seat. :p
 
#17 ·
I still have water leaking at the roof above the drivers and passenger side's electric windows between the front windshield and the corner where the convertible top meets the windshield. The water then trickles down the rubber to each of the junction points where the rubber bends on the convertible top.... =(
 
#19 ·
Water where it's not supposed to be, cont'd

The oft-repeated first solution to try is to find someone who knows BMWs who can clear your car's drains. They get clogged with dirt, debris, bits of leaves and twigs, etc. and can't handle the water, so it leaks into the car. Bad drains in a Miata from years ago resulted in the same problem.

As someone stated in an earlier contribution to this thread, German convertibles don't leak, so yours shouldn't either.
 
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