Mystery water intrusion (1 Viewer)

[wchevron]

Was getting water leaking into the drivers footwell when driving in the rain and washing the truck. Ending up figuring the joint where the windshield and body meet was leaking, only on the drivers side. From the mid point of the truck to the drivers side, I ground out the old sealant, cleaned and re-sealed the joint near the end of last summer. All has been good, in rain (only drove in rain 1-2 times) and also when washing.
Got the truck out of storage this spring, first wash ok. Then driving home in rain storm. No leaks for first 20 min, then quite a bit of dripping from under the dash. Truck was garaged last couple of weeks. Friday night we had some rain and I left the truck out. Mabye a 5" diameter puddle of water under the pedals. Took the hose out and sprayed the same joint again for a few minutes. Really used a lot of water. No leaks. Left the truck out. Must have had rain last night. This morning a 2" round puddle in same spot. Ended up washing the truck and soaked the joint. Still no water on the floor. Even went back 30 min then 1 hr later and no water. Any thoughts?

 

[dazerb]

How are you hood hinges gaskets?
Could be water intrusion past the hinge where it bolts into cowl. I didn't know that was a thing until i threw some cork under the hinge... and water dripping under dash into pedals became a problem.

 

[peesalot]

Cowl vent tubes ? Nevermind, guess the newer ones didn't get that luxury.

 

[charliemeyer007]

Mine leaked a little at the body filler joint seam at the cowl. I just fingered a thin layer of silicon caulk over the joint. I used tygon tubing to replace the drain pipe on the cowl vent.

 

[wchevron]

Where are the cowl vent tubes? I saw some pictures online of their location on a 75 and older (mine's a 77). They appear to be in the cabin but I have nothing in the cabin and didin't see anything in after a quick look in the engine compartment. Found an older thread on this topic and in someones '76 the tubes come down on each side of the heater and through holes in the transmission tunnel. I have no holes in the transmission tunnel?

 

[pb4ugo]

Pull the cowl vent grate and clean it out and look to see if they're are drains in there. My 75 and i think 76 had the drain tubes in the tranny hump. Idk, what they did on later models. What did you use to seal the cowl seam? I've run across older threads where folks would dig out the old stuff in the seam and then reapply with seam sealer. As mentioned b4, I used rubber hood hinge gaskets and used permatex on the screws.

 

[wchevron]

Pull the cowl vent grate and clean it out and look to see if they're are drains in there. My 75 and i think 76 had the drain tubes in the tranny hump. Idk, what they did on later models. What did you use to seal the cowl seam? I've run across older threads where folks would dig out the old stuff in the seam and then reapply with seam sealer. As mentioned b4, I used rubber hood hinge gaskets and used permatex on the screws.

 

[wchevron]

I don't have a cowl vent so maybe no cowl vent tubes? I used an automotive seam sealer on the seam. The paint at the seam around the middle of the truck had bubbled/cracked so first figured that was the issue. Cleaned the seam and filled with sealer. Then re-painted (I know, the paint looks like crap). About a week later it was leaking again. Sprayed with water and did the rest of the seam towards the drivers side. Left it unpainted. This was end of last summer and it had held up until this spring. Have soaked both spots, and the rest of the untouched seam with water. No leaks. Also soaked the hood hinges with no leaks.

Even soaked the rusty spot under the windshield gasket, figuring maybe there it was leaking in there. No water.

 

[pb4ugo]

It could be leaking at the bottom of the windshield where the w/s gasket and the lip of the frame meet. I just went thru rebuilding my frame in that same location in January. I removed the glass and the lip for the gasket was eaten. Inside the frame behind the defrost vent was ate up too. I fortunately had a couple of frames I could scavenge metal sections from.

 

[Mark Jennings]

Had a similar issue on my 68, thought is was the cowl joint…..ended up being water running down the drivers side rain channel (from the roof drain hole) and ‘wicking’ around the door gasket right at the dash seam….Drove me nuts, if I parked on the level, no leaks. If I parked with the drivers side low, 5” puddle under the peddles. Passenger side low, 1” puddle. When driving in heavy rain, windows all shut, drips on my feet….wing window cracked open, no leaks…

Remember, these rigs were designed ‘weather tight’, NOT ‘water tight’.

So now I park on the level or passenger side down hill, and when driving in the rain, wing window or door window cracked open.