'95-'98 models may not have this issue (due to different bodywork), but for '99-'01 owners an advisory:
Pull down your lower door trim strips and inspect the door weld joints for rust. I noticed rust bubbling under the paint of my LR door and found this:
door_rust1.jpg
After cleaning the "wound" with phosphoric acid:
door_rust2.jpg
The only outward sign of trouble was this:
door_rust3.jpg
I think I see what's happening. The lower trim strip mates with the door using a tongue & groove joint. The groove of the trim strip is a U shape which traps water. Although there are drains in the strip, water still lingers. The tongue at the bottom of the door is a weld joint, which may or may not have been sealed with paint. If this joint is open -- anywhere -- water will intrude. Bad design.
After the phosphoric acid treatment, I plan to use Bondo to seal the rusted crack. The outside bubbling is not noticeable unless pointed out, so I'll just leave it.
Thanks for sharing.
How do you remove the trim?
Yeah this is the exact reason why I'm not buying replacement OEM lower door trim. Holding water isn't bad. Holding water and debris is bad! Every vibration makes it cut more and more through the paint which causes the rust. So I'm instead doing something more like this:
529.jpg
The car is being painted obviously, but you can see the lower trim installed there. I bought it from eBay and it works/fits great. This way, nothing gets trapped against the door, AND it's cheap and easy to replace should it need doing at some point. Sure beats paying $200+ just for some lower door trim pieces.
|| 1995 740i || M60B40 || DUDMD || ̶o̶r̶i̶e̶n̶t̶ ̶b̶l̶u̶e̶ Mercedes Brilliant Blue Metallic || Style 168 Wheels 1" Spacers ||
After my Bondo repair to the rusted area, I removed the door panel to check for rust inside the door. Thankfully, I found none. This was a great relief.
All '99-'01 owners need to perform these two checks, otherwise you'll soon be buying new doors.
TIP: If one of your lower door trim strips is resting at a slightly different angle than the others, you probably have rust deforming the bottom of the door. Look closely at my sig pic. Notice how the rear door's trim strip reflects light differently than the front door? The two trim strips are not aligned: not good.
Why Im so glad I got out of Iowa and its overuse of salt in the winter and got down to Alabama. No salt, no rust!
98 740i
98 740iL, parts car for the 740i.
01 540i
I got the same problem with my 98 e38, like each door has some rust, does bondo work well? After applying bondo, is it still possible to install the lower trim?
Interesting your '98 has this problem.
RE: Bondo repairs:
Yes, the trim strip still attaches itself after the repair. The strip has a pliable, gasket-like form which may be tightened either by hand or with pliers. Depending on the length of the rusted area, you may also have some of the original steel form remaining, which helps hold the trim.
I completely sealed off the rusted areas with Bondo (using my finger as if with caulk), to ensure they are sealed from the elements. Your fingers are also helpful to form a smooth surface for the trim to attach. I then primed and painted the Bondo'ed area before reinstalling the trim.
Time will tell how this repair holds up. One thing for sure: it will last longer than leaving the door as is.
Ouch, I too found rust at the base of the door, this one was the front passenger door. The rust made its way up the door a bit. I sanded the rust to get most of it off. Next step is the chemical rust remover. No sign of rust on the other doors. It appears that water can make its way into the pinch weld at the base of the door, rust is inevitable when this happens.
Regarding the trim piece, it would not budge until I put a pry lever at the top of the trim on the inside and twisted a bit causing downforce. I slowly worked the lever from back to front, no need to rush this, didn't want to break the trim.
740i Rust Door 1.jpg740i Rust Door 2.jpg740i Door Rust 3.jpg
2001 BMW 740i - Anthracite Gray - Style 32 Wheels --------- 2004 BMW 330i - Silver Grey Metallic
Convenience Pkg - Cold Weather Pkg - PDC ------------------- Sport Package - Auto - Mroof - Hseats
If those areas aren't rusted yet I suggest either a heavy coat of wax or a coat of grease. I used grease when I put my shadowline window trim on the doors. If they are already rusted I would coat them in something like POR-15, Rust Bullet or similar after cleaning off the rust.
1991 318is
2001 740i
2001 BMW 740i - Anthracite Gray - Style 32 Wheels --------- 2004 BMW 330i - Silver Grey Metallic
Convenience Pkg - Cold Weather Pkg - PDC ------------------- Sport Package - Auto - Mroof - Hseats
Was BMW not galvanizing their bodies during these years? I thought all the Germans pretty much did. I know every Porsche since 1980 has been galvanized. When I searched in the past I got conflicting info on BMW. I figure if anyone knows for sure it's you guys.
When I was showing my 2001 off to a fellow BMW owner at work, the rear passenger trim piece fell off when he got out. As luck would have it I saw no rust when I put it back on. So I got a jump on this, one down, 3 to go!
2001 740iL "Silver Beauty"
1986 Porsche 951 "Silver Bullet"
1987 Porsche 944 NA Auto (rebuilding for my son's first car)
https://home.doonze.net/filepage.php <- BMW/Porsche doc's and files, work in progress
There is an additional factor: keep the door drains clean. Otherwise, water will stagnate and you WILL get door trouble.
Both my front doors have rust along the bottom. I found two rust free doors from the USA (I'm in Canada.... home of salty roads) and I'm going to replace both doors. The replacement doors need to be painted to match the car as they are white and black and my car is neither of those. All the body shops I talked to said metal has to be cut out on the original doors new metal welded in if I wanted to keep the original doors. AND they won't guarantee that work with regards to the rust returning. All said best way is to replace the doors. Costs for door replacement and paint is slight higher but no where near twice as much or anything like that. And peace of mind over the coming years is good on this issue. Now keep in mind that I'm planning on doing the "de-installation and re-installation" all myself.
One of the replacement doors I bought came complete and so I had something to practice on for dis-assembly. That and YouTube made the job fairly straight forward but it was time consuming. Will be interesting if re-assembly will be a seriously painful adventure. Just so we're clear, the replacement doors I stripped off EVERYTHING except that large main gasket that is glued on and glued in a very specific and non-linear location (see attached picture). I didn't want to mess with that or don't think I want to mess with that......... unless someone tells me otherwise and that re-application is a breeze because there is a guide on the door or a template.
20190425_191842.jpg
Last edited by tominizer; 04-30-2019 at 03:55 PM.
Tom
Garage - 2000 750iL -- 2007 Z4M -- 2012 35d X5 mod'ed -- E30 M3 red valve cover -- tools -- misc BMW junk
Are the upper half of the hinges still attached to the door. Not sure about removal of the gasket though. Let body shop deal with it maybe??
Check TIS for info. A start:https://www.newtis.info/tisv2/a/en/e...nents/8HthLMFy
Last edited by clarkitect; 05-01-2019 at 03:49 AM.
@clarkitect - Not sure. I have to check that. Good point. I've found that gaskets like this can be hit and miss. I'd prefer to remove it but I'm just really unsure about the re-application and getting it right. I think what I need to do is make a paper template of it's location all around the door. I'm not trusting a body shop as I've found in the past that people just generally don't give a sh!t about my car like I do. And I haven't even checked if the gasket is still available and it's cost.
Tom
Garage - 2000 750iL -- 2007 Z4M -- 2012 35d X5 mod'ed -- E30 M3 red valve cover -- tools -- misc BMW junk
My 2000 beginning to show rust only front passenger door. Thought would be easier/cheaper to just replace the door from a parted out car when the time comes (not knowing that this is a common problem with most).
Per OP, 95-98 doors do not have rust issue. Do the older doors fit 2000-1 models? Alpine white anyone?
Someone a lot smarter than me with these cars also noted that the earlier doors are NOT the same as the later doors......... .with regards to mounting points of the various pieces of hardware that have to go back on...... such as air bags, etc.
Tom
Garage - 2000 750iL -- 2007 Z4M -- 2012 35d X5 mod'ed -- E30 M3 red valve cover -- tools -- misc BMW junk
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