how to remove the foamed-in rubber sunroof drain tube from inside the A pillar? - AudiWorld Forums

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how to remove the foamed-in rubber sunroof drain tube from inside the A pillar?

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how to remove the foamed-in rubber sunroof drain tube from inside the A pillar?


Old 02-11-2018, 06:18 PM
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Default how to remove the foamed-in rubber sunroof drain tube from inside the A pillar?

I cut the 1/2" rubber hose from the right front sunroof drain inside the passenger A-pillar with a 3/4" holesaw about 6" above the dash, from the inside. (Can you say "butcher"? Made an access hole that I'd hoped would let me bang out a dent from the inside. Big oak tree caved in my garage roof and fell on the car on the lift. Smack dab on the A pillar, breaking the windshield. Audi space frame - wow! Just a 0.025" depression in the windshield mounting surface! That's 1/40 inch, smaller than 1/32"! The car has a roll cage! Saved my '67 Pontiac Firebird ragtop on the other lift, too. The windshield mounting adhesive was way more than thick enough to take that amount up.) Didn't blow through the other side of the space frame A pillar box; just had a windshield put in the car and left the 4" long dent without banging it out. Good enough, and a conversation piece. The molding was destroyed by the tree, and instead of buying a new one for $400 I let the windshield guy give me a free rubber molding that is cut off a roll. Top corners don't cover the gap, but at this time, good enough.

Of course the the long A pillar trim piece that adjoins the headliner is off (so I could butcher the A pillar). Saw the drain tube exiting the headliner and going down into the A pillar. The tube is polyurethane foamed in (like "great stuff"), at least near the top. I was trying to pull it back up out of the A pillar, and tore the tube up with vise grips. So now the tube is in 3 pieces - top one from the sunroof drain hole into the cabin, middle piece from the cabin down inside the A pillar to the holesaw cut, and the bottom piece from the cut to the door hinge area. I already took off the rubber exit nipple there. Even that part doesn't seem to be moving when I pull on the tube at the exit.

How do these tubes get replaced, with them foamed in like they are? That stuff is also used for glue (Gorilla glue). I don't know of any solvent that'll dissolve that stuff. Is the tube supported any other way? If I can get the foam and the tube out, I think I can fish a new tube in. I may try to put a connector under the trim to connect with the top piece, so I don't have to take down the headliner to replace the top piece of tube. The rubber seems in good pliable shape.

How about some long flexible drill bit; is there such a thing? I'd think electricians might have some thing like this. Just run it up and down left and right inside the A pillar till I chew enough foam out to be able to pull the tubes? How do the dealers do it?

Last edited by hillpc; 02-11-2018 at 06:24 PM.
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Old 02-27-2018, 06:14 PM
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Default fixed the leak by inserting a new tube inside the old one

Using a steel fish tape, and 10 gauge insulated wire as fishing/guiding devices, I ended up being able to push one continuous length of 3/8" OD 0.060" wall white polyethylene tubing (~1/4" ID) the whole length of the right front sunroof drain, inside the existing ~12 mm ID (a little under 1/2") rubber tube. Started pushing the tubing in at the door hinge area (outlet). (Pulled off the outlet rubber fitting first.) Sealed the very small annular gap at the inlet, between the inlet and the slightly smaller 3/8" poly tubing with sticky black 3M Windo-Weld Resealant (Flow Grade). It's made for resealing leaks around windshields, and "dries fast into a flexible, rubbery seal", according to the can. Maybe I could have used silicone or something else, but I had it sitting on my shelf. I had first planned to use a compression fitting to barb fitting to make a joint from good rubber to poly under the A pillar trim near the roof, but decided there wasn't enough room for all that under the trim. So I went the entire length end to end with the insert.

I was fighting the pop-up air deflector at the front of the sunroof blocking easy access to the inlet to get to that area to do the sealing, until I read the Bentley and saw that the deflector is literally less than a 60 second job to pop off by hand. Push back to unclip both sides, bend one side in about 1/4" to clear a stop, and lift off. Both front Inlets now in plain view.

I had earlier tried a 1/4" drill bit (to start with) on a 54" long (somewhat, not very) flexible drill bit extension (electrician's tool for drilling inside walls) to chew out the polyurethane foam in the A channel in an attempt to free the original tube, but ended up chewing up the already broken rubber tube some more, and not getting enough of the foam out to release the rubber tube, before I came up with the insert idea. The ID of the whole drainage tube on the right side is now of course smaller, 1/4" vs a little under 1/2", but the inlet actually seems to be the bottleneck in the original tube, being only a little over 3/8" . I hope the smaller ID is sufficient during downpours.
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