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And you wonder why the front sills and floor rust ?

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olympia57
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And you wonder why the front sills and floor rust ?

Post by olympia57 » Sat Apr 12, 2014 7:26 pm

Working my way through my car removing every bit of rust on it .
Whilst removing the bad areas at the bottom of the LH A pillar / floor I had the chance to look up into the sill ( Rocker ) and found the reason for the rust...
The sunroof drain terminates about three inches from the base of the sills and has obviously never been directed through the purpose made drain hole in the A pillar .
Shame on you BMW
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Post by wattsmonkey » Sun Apr 13, 2014 2:33 pm

...although, my parts car, with no sunroof, had all of the usual floorpan/sill/jacking point rust.

The rear window [non]seals are the biggest culprit, I reckon, especially once they start cracking up. I think that's why E28s tend to be less rusty, despite same stupid sunroof draining system.

[Yes, I know E28s can be very rusty, too!]

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Post by Brucey » Mon Apr 14, 2014 6:19 am

yes it is all a rotten business, isn't it....

I have taken 6ers apart and been VERY unhappy with the sunroof plumbing too. For example, the clips never being attached to the drain hoses at the roof itself, and the drain tubes just stopping 4" up from the windscreen lower edge inside the A pillar. Crazy.

However there is another explanation for the tube not poking through the hole like that; the tube could have shrunk lengthwise over time. This can happen with certain types of moulded rubber and plastic. However my money would be on it never having been done right in the first place.

I wonder if we should blame Karmann or BMW for this? The bodies were shipped from Karmann in primer to BMW as I understand it. If Karmann were meant to fit the drain tubes then we can blame them for not doing it and BMW for not checking it.

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Horsetan

Post by Horsetan » Wed May 07, 2014 1:33 pm

Sunroof drain tubing can also come adrift at the top due to the metal tube connector corroding.

I have managed to patch this for now using a conical tube connector and a flexible rubber substance called "Sugru".

I will probably need a whole new roof skin anyway, as a section corroded on the offside next to the sunroof opening, and the resultant rusty hole was patched temporarily by a friend using what appears to be either Isopon or Plastic Padding.

*sighs heavily*

The sunroof still works, though.....

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Post by ron » Wed May 07, 2014 3:26 pm

Horsetan wrote:....I will probably need a whole new roof skin
I can sort you out with one. Any particular colour?
They are ALWAYS rustier than you thought!!!!!!
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Horsetan

Post by Horsetan » Wed May 07, 2014 5:33 pm

ron wrote:
Horsetan wrote:....I will probably need a whole new roof skin
I can sort you out with one. Any particular colour?
Errm....something vaguely burgundy might help...

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Post by ron » Wed May 07, 2014 5:35 pm

Horsetan wrote:
ron wrote:
Horsetan wrote:....I will probably need a whole new roof skin
I can sort you out with one. Any particular colour?
Errm....something vaguely burgundy might help...
How about Misano Red?
They are ALWAYS rustier than you thought!!!!!!
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Horsetan

Post by Horsetan » Wed May 07, 2014 5:36 pm

ron wrote:
Horsetan wrote:
ron wrote: I can sort you out with one. Any particular colour?
Errm....something vaguely burgundy might help...
How about Misano Red?
A bit bright, but beggars can't be choosers, so!

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Post by bakemono » Sat May 17, 2014 8:35 pm

Brucey wrote:However there is another explanation for the tube not poking through the hole like that; the tube could have shrunk lengthwise over time. This can happen with certain types of moulded rubber and plastic. However my money would be on it never having been done right in the first place.

I wonder if we should blame Karmann or BMW for this?
I say it was BMW. The sunroof draining into the rocker panel is the same on e21, e24, e28, e30 and probably others. On an e30 I saw a rust hole up under the dashboard that went to an inaccessible cavity which is supposed to allow drainage from the air intake below the windshield. I suspect that water entering the c-pillar vents on my e28 may be the cause of my wheel arches rusting. There is definitely a common theme.
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Re: And you wonder why the front sills and floor rust ?

Post by BenM635i » Tue Jun 09, 2020 11:22 am

olympia57 wrote:
Sat Apr 12, 2014 7:26 pm
Working my way through my car removing every bit of rust on it .
Whilst removing the bad areas at the bottom of the LH A pillar / floor I had the chance to look up into the sill ( Rocker ) and found the reason for the rust...
The sunroof drain terminates about three inches from the base of the sills and has obviously never been directed through the purpose made drain hole in the A pillar .
Shame on you BMW

Image
Afternoon all and old thread time!

Am doing the yearly dinitrol session and decided to lift the carpets to check the floorpans and get a good spray inside the sills.

Thought i may as well check the sunroof drain pipe exit spot while the speaker and panel is out and yep.. they are short and currently drain into the sills. BMW definitely were not thinking long term when they fitted the hoses, don't understand why they wouldn't run them an extra 6" or so and out of the sills! Just can't think of the logical reason to have water drain into the sills when there are holes obviously designed for the guage of pipe to run outside :-k

Ill send photos if anyone is interested.

Wondered if anyone has successfully extended the pipes out the bottom of the sills while the car is still intact? Can see its easy to do if the floorpan and inside sill is out but access is very limited with the car whole.

Thinking that it's possible to get a smaller pipe up from under the sill and join it to the existing. Problem is the original pipe is quite firm and its not possible to pull it up to get access to the end. The only way may be to get at the top where the pipe attaches to the sunroof drains, disconnect and pull up until i see the end.. join new pipe to end then push the pipe back down and re-join the top to the sunroof.

Any ideas?
'85 M635 #160

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olympia57
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Re: And you wonder why the front sills and floor rust ?

Post by olympia57 » Tue Jun 09, 2020 4:46 pm

If you remove the speaker and trim from the A piller under the dash you will be able to get to the black drain pipe through the speaker aperture on the metal face .It's a little awkward but doable . I used 15mm OD plastic water pipe that was a good interference fit into the original black drain pipe . This can then be routed out the manufactured hole on the base of the A piller itself.
I'm sure that this oversight has contributed to the demise of many an E24 .
Good luck .
Don
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Re: And you wonder why the front sills and floor rust ?

Post by BenM635i » Wed Jun 10, 2020 7:44 am

Cheers Don - you have given me some hope that this can be done. Tricky bit will be pulling the very stiff tube around so as to get access through the speaker panel but it shall be done somehow.

Have ordered 2x different OD 15mm water pipes from ebay and when they arrive will have a go and report back.

Strange that BMW seem to stop the sunroof drains above the exit hole and chose to drop any water into the sills. Wonder if all e24 were plumbed like this, has anyone confirmed their drain pipes exit below the sills by default yet i wonder?
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Re: And you wonder why the front sills and floor rust ?

Post by BenM635i » Tue Jul 07, 2020 3:21 pm

Spot on Don, thank you for the guidance.

Just completed offside sunroof drain plumbing, now anything that gets past the sunroof felt seal will actually exit under the car instead of into the cills #-o

Will do the nearside over the coming days.

1) pull original drain tube up through into cabin, as Don says the speaker enclosure makes this possible and gives anough access to bend the tube and get the end out.
2) 2x coat hangars, small hook on each end. Push one down from cabin until you pop out of the hole in the inner wing. Look in from underneath with car jacked up then use second coat hangar to hook first, pull and twist and pull some more till the coathangar from cabin is with you under car.
3) duck tape 15mm o/d water tube (bought clear and flexible from ebay for a couple of quid) to the coathanger. Found making a little hole in the pipe then using my existing little hook on the hangar to hook this then adding a single layer of duck tape worked well. You want things slim and smooth so as to be able to pull the tube up.
4) gently persuade from inside the cabin... taaaa daaaaaaaaa tube comes up.
5) attach new tube to original, as Don says interference fit with new inside old, nice snug jubiliee clip to compress then some silicone on for good measure.
6) give up for the day as its raining and the job isnt fun. Mainly due to the gallons of dinitrol that i keep in my sill area and have topped up over the last 10 years :D

Would absolutely say worth checking your 6 series... if you look up from under into the inner wing area and see a hole with no tube then its worth doing. Assuming you have a sunroof of course.
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Re: And you wonder why the front sills and floor rust ?

Post by olympia57 » Tue Jul 07, 2020 3:39 pm

Well done Ben , I'm glad you managed it .
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Re: And you wonder why the front sills and floor rust ?

Post by 635sharknose » Tue Jul 07, 2020 3:54 pm

This is an interesting topic! Will get into speaker area to check mine too.
Thanks for the info guys.
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Re: And you wonder why the front sills and floor rust ?

Post by Ronnie Wilson » Sat Jul 11, 2020 5:18 pm

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Hi

Just completed the same task.
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Re: And you wonder why the front sills and floor rust ?

Post by Ronnie Wilson » Sat Jul 11, 2020 5:49 pm

Hi

If you want the original drain tube, it’s available from Walloth and Nesh.

Thanks
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Re: And you wonder why the front sills and floor rust ?

Post by Mr._Graybeard » Sun Jul 19, 2020 9:00 pm

IMO it's not the sunroof drains that cause rust as much as the dirt and vegetative junk that falls through the cowl and fender drains and into the fender wells. Water from the drains (including the sunroof) keep the gunk moist, producing a fertile environment for rust. I try to open up my front fender linings at least every couple of years to hose our the compost that's deposited therein.
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Re: And you wonder why the front sills and floor rust ?

Post by olympia57 » Mon Jul 20, 2020 8:42 am

Mr._Graybeard wrote:
Sun Jul 19, 2020 9:00 pm
IMO it's not the sunroof drains that cause rust as much as the dirt and vegetative junk that falls through the cowl and fender drains and into the fender wells. Water from the drains (including the sunroof) keep the gunk moist, producing a fertile environment for rust. I try to open up my front fender linings at least every couple of years to hose our the compost that's deposited therein.
In interesting hypothesis but incorrect.The sunroof drains directly into the internal cavity of the sill /rocker .
The external bulkhead drain ( under the bonnet louvres ) goes into that area behind the inner wing splash panel and that is where the moisture that you speak off originates from.
Fit a fine mesh gauze over the drain port inside the engine bay and/or better a pair of Lokari liners and your problem is vastly reduced ,if not eliminated.
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Re: And you wonder why the front sills and floor rust ?

Post by jsspagg » Tue Sep 28, 2021 5:35 am

Good stuff for sure. I recently made the same conclusion about the bad design with the short drain tube. I will definitely be making the extension to drain outside of the sill.

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Re: And you wonder why the front sills and floor rust ?

Post by jsspagg » Wed Sep 29, 2021 5:07 am

Since my interior is currently out and fenders off after some rust repairs, decided this is the best time to accomplish the sunroof drain hose extension task. After reading the input from above, I had a pretty good idea of what needed to be done. Using what I had on hand in the garage I got after it. Once I figured things out, took about 20 mins to do each side.

Supplies used on hand:
1) Continental hose (the hose intended to connect the top of the radiator to the expansion tank. The OD was close to 13 mm, which is about the same ID as the existing forward drain hoses.
Note: I had a piece of this hose on hand that was about 18" long t start. Ideally, you have two pieces about 14 inches long- makes it easier to work the process.

2) Anchor Marine Grade Heat Shrink Tubing 3" long 3/4" diameter

3) Penitents- tried a few tools and methods. You will benefit from the above reading as well as my notes below to accomplish this task. It certainly helped that a good part of the car is stripped down and I did not need to remove anything to access the areas needed.
Steps:
1) Pulled out the existing drain hose into the cabin through the oval cutout below the speaker hole cutout. This was a bit of an effort and required finger strength and patience.

2) Cleaned the inside of the drain hose with a cotton ear swab and spray cleaner about 3" up into end of hose.

3) Slid a piece of Continental hose up into existing drain hose. Fit was snug so I used a little spray cleaner to assist in sliding/pushing on. I insert hose approx. 1.5 inches into existing drain hose.

4) Slide heat tubing and center on cross section and apply heat.

5) I insert a long Philips screwdriver (8 inches long) from the outside (of the car) of the sill where there is an existing hole. Back on the inside, I insert the end of the new hose extension onto the Phillips screwdriver and used that as a guide to pull the hose through the hole in the sill and to the outside of the car. When the fenders go back on, I will trim the excess hose to the appropriate length.
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Re: And you wonder why the front sills and floor rust ?

Post by Jlc » Sun Oct 03, 2021 10:37 pm

Question - can you access the hole in the sill with the fenders (wings) still on?
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