1986 Chevy C10 Silverado - Water Leak - Cowl Drain and Inner Kick Panel Rust

[Mike86c10]

This post is more to share my experience with working on a leak problem.  This is my first truck, and I have little to no previous experience working with body issues and spent many hours researching other sites and forum posts to get to where I am now.  I figured I'd post it here to possibly help somebody in the future.

Here's some pictures:
http://imgur.com/a/lgrpJ

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So I bought an 86 C10 a few weeks ago.  Overall it's in really good shape.  The new engine and drivetrain has less than 30K miles on it. The body rust is minimal - just a few spots that need fixing behind the rear wheels and couple spots on the doors.  I was planning on just enjoying it as-is until next spring when I would put some sweat and money into it.

Well it rained pretty good one night, and the next sunny day my friend said, hey your rug looks wet.  I thought maybe I had the door cracked when I washed the car, but no, I came to find that water was leaking from somewhere within the cab.  So at this point I started my - 'dang it my car leaks water' project.

Ok considering that your leak isn't coming from the doors or window seals, you probably have clogged cowl drains and a cowl leak.

I'm going to get straight to the point here:



***Pinpoint the Leak Location(s)***

Remove everything in the cab that hides where the water is coming from:

-Unscrew the floor molding that holds down the rug on both sides of the cab

-Pull back the rug

-Unscrew the drivers side kick panel molding (my car has A/C, this side is easy)

-Remove the Passenger side kick panel molding.  (This is a little more work.  Remove the glove box to get access to all the bolts easier. The molding sits flush in the air vent on this side.  I had to twist and turn it a bit to get it out.)

-Remove all the sound and heat dampener insulation on the firewall from under the dash. (don't worry, you can buy this stuff and reapply it)

At this point you can pour water into both sides of the cowl and wait to see where the water is coming from.  In my truck it comes from 3 different spots - YAY .  keep that in mind because its time to clean the cowl drain.

The 3 spots on mine are:
Driver's side - the seam where the inner kick panel meets the floor panel is rusty and has some small rust holes.
Passenger side - a nice larger rust hole on the inner kick panel.
Driver's side under the dash - Still haven't pin pointed the location but it drips from the wires behind the fuse box.

Here's an exciting video I made of water coming in through the rust hole.
http://www.youtube.com/watch?v=qcwLjEYXwgM



***Clean the Cowl Drains***

-Remove the wiper arms, cowl cover, and clean out the gutter

I used this post to help me out:
http://forum.73-87chevytrucks.com/smforum/index.php?topic=12521.0

-Step 1 - buy a wiper arm removal tool! -
http://www.amazon.com/gp/product/B000CODS80/ref=ox_ya_os_product

I wasted a full day and scratched the paint on the cowl cover trying to use screwdrivers and pliers to remove the arms.  The wiper arm tool worked perfectly with no effort ($4 overnight shipping with amazon prime  )
 
-I removed the wiper fluid hose from the wiper arms, I'm sure that will be a small project getting them back in later.

-There are 4 bolts for the cowl cover and 2 bolts for the cowl screen. (if my memory is correct)

-I didn't remove the hood of the truck like recommended in the above post link, so I taped over the cowl cover edges to protect the paint. (I actually put tape on after I accidentally chipped some away    )

-Working alone is difficult but I was able to get the cowl cover off after some really tight maneuvering - I almost gave up.  The second time I took it off I had a friend help and it was almost easy.  Putting it back on alone is a severe pain in the  too (all due to the hood being in the way).

-Once you gain access to the gutter, clean out everything that's not metal.  I had mud, leaves, dirt, and a mouse nest which was a big ball of insulation. 

NOW CLEAN THE DRAINS INSIDE THE FENDERS (a little more difficult to access)

-I started with the passenger side since the vent hole is there in the inner kick panel.  I was able to reach my arm down and clean out the crap. 

-Clean out the drains from under the car.  Underneath the car, behind the front wheels is a plastic molding that connects to the wheel well. This is to prevent debris from going up in your truck.   From the bottom, they aren't screwed in, they are plugged with those xmas tree plugs.  On the drivers side I just basically broke the plugs so I could get access.  There are also screws that hold the plastic molding to the wheel well.  I unscrewed them as best as I could, it uses some type of clip to screw into.  Getting them back on properly will be a pain, but I am worried about the clog right now.

Once you gain access, you can reach your arm in there (wear goggles!).  Feel around for a small opening that is the bottom of the cowl drain.  I used an unbent metal hanger to go up the hole to dislodge dirt.  I also stuck the hanger down from the cowl gutter.  I was able to feel the hanger from underneath when I stuck it down from above.  So I knew for sure where the bottom of the drain was.

On the passenger side I didn't need to unscrew or break any plugs.  The plastic molding was shaped in a way that I could just reach my hand up in there. 

Ok, so now that the dirt is free, you can test further for your leaks and prepare to make the necessary fixes.

------------------------------------------------------------------------ 


***The Fix***

So I actually am at this step of my project now. I plan on doing the following:

-Silicone caulking (for metal) inside the cowl gutter, over the old seal that you can see in the pictures I posted above (I actually did this last night). I feel that this will fix the leak from under the drivers side dash.  I will get to test this tonight after it has cured for about 24 hours.

-On the kick panels, remove as much rust as possible, rust proof the area, and then put fiber glass patches over the holes. 
I still am researching the best way to do this.  I will have to buy all the necessary tools and supplies as I only have some screw drivers and sockets at my place (and the wiper arm removal tool!)

Oh and on the drivers side floor board, under the rug, there is a lot of surface rust from the rug being wet.  I will have to clean that as well. 


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Things to note:

I went to a body shop to get an opinion on the kick panel rust holes.  Shockingly, he told me to figure out how to patch it myself, that it wasn't worth making a small problem big by cutting and welding.  He also told me to figure out the dash leak myself too, cause it would be silly for me to pay garage time to find a leak.  Honest guy.

I bought a truck cover (the middle tier one) to help block rain until I fix the problem.  I haven't unboxed it yet, I still have a blue tarp over the cab.  But I can report back as to how well it does in the rain.  I can't find any reviews on the net.   

Links related to cowl leaks:

Clean cowls:
http://forum.73-87chevytrucks.com/smforum/index.php?topic=12521.0

Mustang Cowl repair:
http://www.stephanies-mustang.com/cowl2.htm

Rusty Kick Panels:
http://67-72chevytrucks.com/vboard/showthread.php?t=45978

Firewall and Cowl Rust (great pictures):
http://forum.73-87chevytrucks.com/smforum/index.php?topic=10512.0

Water Leak in the cab
http://67-72chevytrucks.com/vboard/showthread.php?t=301266




 

 


 

[Mike86c10]

Update:

Found a rust hole in the firewall covered up by black tar or caulking of some sort behind the wiper motor. This is where the dash leak is coming from.

http://i.imgur.com/GUywQGKh.jpg
http://imgur.com/a/lgrpJ  (The full album link again)

So after letting the caulk cure in the cowl drain for 24 hours I tested the seal by pouring water in the drain.  Unfortunately, its still dripping in from under the dash.  So I decided to find the leak from under the dash.  I ripped out more insulation and felt around towards the cowl (since I can't see past the wiring harness).  I was able to find a nice wet rusty hole on the firewall and poke my finger through.  I looked at the firewall from under the hood and pinpointed the other side of the hole was behind the wiper motor, cover by black tar / sealant.  I noticed this black tar before but didn't know what it was for, I thought maybe it was to seal up legitimate holes and gaps, not rust.  There's more of this tar along the firewall behind the air cleaner, crossing my fingers on that one. 

I assume what I have to do is remove the wiper motor and remove all the tar.  Then maybe grind away all the rust and fix the area somehow. 

[bedanwilles]

Hey, it seems really a big problem  
Have you tried to repaint those parts?? or Do you travel your car in lots of wet areas??
Contact your dealer as early as possible or else I think the day would come when the whole car would be rusted