Cab leaking

[jeffbo]

I was just curious if anyone else has a problem with water leaking into their cab under the truck dash. Is it a common problem with this body style, or is it just my truck? It's been raining here for 2 days and everytime I get in my truck there is a small puddle of water in the front corner of the floor near the kick panel, on both the driver and passenger side. It appears to be coming in under the dash because my parking brake pedal and wires under the dashboard have water dripping from them. Also, the inside of my glove box got full of water and soaked everything in it. The back righthand corner of the glovebox is falling apart because it has soaked up so much water. So, anyone have any ideas? Could water somehow be leaking in between the back edge of my cowl and the windsheild weatherstripping? It's kind of hard to describe exactly, but I thought maybe someone else has had the same problems?

[CPNEJR]

I'd tell ya what the problem is if I knew I've heard of water leaking through the top corners of the windsheild and bottom corners of windshield but never under the dash.

[BLACK AND BLUE 67-72]

Check the winshield, and pull the cowl and check the seams under there. Also how is your driprail? If it is cracked it could be leaking from there. Other than that I cant really think of anywhere else.

[Hotrod70C10]

I have the same problem, It is most likley the sealant in you drip rail above the windshield. You should take a wire wheel and get all of it out then, use a sealer for that purpose. I know if you let it do it for very long the metal around your windsheild will be nothing but rust... also the inside of the cab will start to rust out.

[jeffbo]

How could it be my driprail though if I have water under the dashboard?

[BLACK AND BLUE 67-72]

Because it runs down the A-pillar doun under the dash or does like mine and puddles on the dash until it leaks through to the floor board.

[SLT'S 68]

I would agree with those guys, this is a pic of a truck I just bought and this is what happens if sealer in rail starts leaking. I can't wait to try and fix this.

[crazy4chevs]

I would say at least a 75% chance of it being in the cowl area.

[Longhorn Man]

Every truck I have owned had the cowl leaking. A common area is where the antenna wire comes in..even more probable if the antenna has been removed.

[72c10step]

Originally posted by Longhorn Man
Every truck I have owned had the cowl leaking. A common area is where the antenna wire comes in..even more probable if the antenna has been removed.

I should check that area of mine. I have the same problem, but I know at least some of my leak came from between the windshield and the weatherstrip on the lower passenger side of the windshield. Maybe some more water is leaking form the antenna hole (I have no radio right now). I'll have to remember this when I bring my truck out in the spring. Thanks Longhorn Man!

[krazy_texan]

mine leaks on the passenger side but it is because there is a rust hole under the windshield seal

[Southpa]

Pull the cowl, lots of leaves and crap likes to settle in over the years. Feel around on each side and see if the drip rails are still intact. I cleaned about a pound of dirt, thats what leaves turn into after a while, and chunks of rust which used to be my drip rails. The water is supposed to be channelled out and down between the open area of the rear part of the fender, just before the door. I figure you've had water backing up and causing rot under the cowl area. It then seeps down and falls inside under your dash.

[SWEET7T]

jeffbo...
Mine is doing the exact same thing. I'm voting for it having a rust hole somewhere in the cowl. I already sealed my drip rail up, so I'm 99.9% sure it isn't that.
I haven't had a chance to do this yet, but try shining a bright light down through each side of the cowl while its dark or in a garage, and then look under your dash and see if you can see any light coming in... Then you know what/where your problem is.
Good luck

[beautimus]

ok, i'll give this a try,
starting from the top, uh roof i mean. (somebody jump in here and help me if i miss one.

1. roof gutter, look for cracks in the sealer.
2. top sides and bottom of the windshield gasket.
3. top and side of the door gasket, (blowing rain)
4. under the cowl cover, cowl to lower windshield frame seam.
(there should be about a ton of sealer in the area directly below
the windsheild to door pillar.)
5 firewall gutter just below the cowl cover(where the wiring harness runs across the fire wall). there are actually 2 seams here. one in the bottom of the gutter and the other is hard to see in a truck thats all put together. if you look at the outer lip of the gutter . the seam is where the 2 sheets of metal come together to form the lip. its spot welded together and the 2 pieces tend to separate. the way to check for this is to grab the lip with your fingers and thumb and try to squeeze the front and back together. if it has separated there you will feel the two pieces give and compress. i dont have a clue how to fix this one properly.
6. this one i am not sure about, if the rain goes in through the cowl , how does it go out? if there is a weep hole for the water to drain, and it getss stopped up , i assume it wil get into the cab that way.

did i miss any?
hopethat helps , Tony

[gonebad2]

Hey Tony, here is a pic for you. I just tore this cab down and repainted it.. Look just below the windshield flange. The original seam sealer was like chalk. One of the other members suggested using a wire wheel to clean the old stuff out. That is the way I did it too. It worked great. You might need a small toothbrush sized stainless steel brush to work the tight spots. 3M makes some really good body seam sealer, You can get the type that you brush on or the style that goes in a caulking gun. I prefer the caulking gun style for this area. Put a good amount in there, wear a rubber glove and push it hard into the freshly cleaned out seam. Then, smooth it out real good so no water will pool up in there. I live in Nevada, it's dry here so rust is not much of a problem. But the sun just bakes everything. BTW....When I cleaned the cowl pockets out, I found a hornets nest about the size of a softball....Take Care

[beautimus]

thanks gonebad2,
thats exactly where i meant,
also check out this pic for the separation on the outer cowl lip to firewall seam. i cropped it out of one of the other members photos, i can't remember who but it was a really clean low miles truck, i hope they don't mind me borrowing it.

[1969 GMC]

my truck has a few small rust holes in the firewall, about where the arrows are in that last pic. mine only leaks on the drivers side, from 2 different places. i think some must drip thru the firewall, cuz occasionally i will feel drips on my clutch foot. then, the side of my windshield seal leaks, and that runs all the way down to the floor. also my inner kick panels have rust thru, so i'm scared to see what i'lll find in there. gotta love teh salt belt

[krazy_texan]

smoke test it, pressurize the cab and some how use smoke off of a cigarrette or something else and just hold it close to where you think it is leaking and see if it goes through, thus finding your leak

[Yukon Jack]

I had rust holes on both sides of my truck in the area that is circled. Nice to have it fixed now.

[Hutch]

jeffbo
My theory is gravity plays a major role in the whole process.
Try testing from the top down with a water hose.

[71-longbed]

another thing to check is the antenna seal ... mine was seperated slightly and letting water right down the side of the kick panel and to the floor ... check both the outer seal and the inner ..... hope this helps

[Truck Hippy]

Give this a look-see to. There is a small hole on each of the dash where it meets the windshield. If your windshield leaks any at all it will go through this hole and drip on the floor under the dash.

[72MARIO]

I welded thoes seemes up. the should be no more problem's once the truck is back together.

[72MARIO]

here is the top

[jeffbo]

Thanks for all the replies guys. Lots of goog ideas. Now I just have to check out all these possiblities. How exactly do I remove the cowl? Where are the fasteners that attach it located?