80 Series A/C Drain Tube and Wet PS Floor...Solution

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Jan 16, 2003
Let me start by saying there are several reasons 80 owners have wet floor boards. One cause is the sunroof drains being clogged the other is the windshield replacement, if done, was installed incorrectly. And lastly, the A/C evap drain tube.

I checked the sunroof drains periodicly to make sure they remain clean which they are, second the truck is kept in the garage now so it hasn't seen rain in over 6 months, I decided to do some recon work to find out why the floor was so wet and found this conclusion. The drain tube is visible from passenger side just under the glove box and goes through the firewall about 2 inches. Personally I think the tube is to short but because of the heat shield on the firewall side it can't be much longer.

With the truck lifted and the fact I am missing one section of the rear inner fender flap I was getting to much wind/airflow in the area of the wheel well blowing the water back in through the cab on the bottom of the hose. One might not think that much water comes out of the tube but drive your truck a little bit with A/C on and then park it and look under it, if draining properly you will notice a nice sized puddle of water. If you don't then you need to check for a clogged evaporator by pushing a ziptie into the inlet of the evaporator to see if it gushes water out. This is noticable by a small drip initially with tube removed.

So after thinking it through I was going to extend the house but the angle it would require would prohibit flow through the house. I have my OBA line running just to the left of the drain tube so I decided to use a Sharkbite 90 degree elbow (3/8" and maintains size of water outlet on original tube.) as seen in the picture and direct it 45 degrees so the water exited as it should just down and away from the wheel well, I have since driven 50 miles with AC running and no longer have a wet passenger side floorboard.

Hope this helps others who might be experiencing this issue, I searched the forum extensively and found little information on the drain tube, all about the sunroof drains, but again check the sunroof drains first. This issue was very obvious once I pulled back the carpet and drove the truck around town with AC on before making the repair.

Sharkbite barb fitting.jpg
You are correct Sir about all of the above.

And that is a outstanding fix for it that i will have to put in my good to know stuff on these things to simplify things.
Great fix Greg, never even crossed my mind! Thanks
black nozzle on the passenger side firewall

let me see if I can find a picture

Could someone provide a picture of where this drain is located? Pretty sure I have the same problem. Thanks
Man and here i thought ole greg came back to an 80.

Ill be back home in a bit and can snap a pic. Its passenger side center of footwell approx. aw heck never postedHere ya go. A 1fzrig
Update: I’ve ruled the drain tube out. Water is getting in when the truck is sitting when it rains hard. Funny thing is I can drive through a monsoon and the passenger floorboard is bone dry. Where’s the leak?
Colud be you windshield gasket. when you replace the windshield you're supposed to put adhesive on both sides of the gasket most people don't. They just glue the windshield the gasket they do not glue the gasket to body.
This will sometimes cause a leak on the passenger side corner. my thought is as you're driving the wind is pushing the water away from that corner but when it's sitting still the the water just drips down towards it.
Could be. The original windshield is still in place with the VIN number on it so it's never been replaced to my knowledge and I have all the maintenance records from the original owner. Maybe the original gasket needs to be resealed.
It's likely your sunroof drain tubes. First thing to do is to pull a couple of the plastic rocker panel plugs out to see if water is sitting in the rockers. If so, that is what is preventing the sunroof from draining. If you pull the rocker plugs and no water comes out then try fishing some weed eater string down the drain tubes from the sunroof trough to clear any obstructions from the tubes. The weed eater cord should go all the way down to the rocker. Listen for it. If you did it right, you'll hear it tapping down in the rocker panel.

The rocker panels are supposed to drain through little slits that often get full of dirt and debris and get stopped up. I know I drained about two gallons out of the passenger side of my truck. I decided to pull the rocker plugs out and I have not re-installed them. There are several different fixes for this issue. One method removes one of the two lower front fender bolts to use the hole as a drain. Another method involves extending the drain tube down through the bolt hole and yet another pulls the drain tube out of the rocker, pulls a body plug out of the floor and routes the drain tube through the floor behind the kick panels. 80 sunroofs, in general, are a pain in the ass and the drains are a serious design flaw.
In addition to daves comments there are are also twonolastic moulding pieces that deform inside the sunroof track and allow water to flow away from the drains.

Your headliner and/or A pillar is not getting wet correct?

If you suspect windshield not definitive but look at bottom inside corners for wet silty debris.

Sorry. I see my pic of a/c drain tube did not load

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