Hello,

Today I decided to finally get into where the source of leaks my truck has are so that I can one day put something on the floor without worrying about it trapping moisture and causing rust. The cowl panel came off easy enough once I figured out this was best accomplished with the hood down, not up. I found that my ducts were actually very clean, with just a little bit of plant debris at the bottom, and best of all, barely a trace of surface rust anywhere. The only rust I found was in the cab where it'd been trapped under the weather stripping on the passenger side, and the floor mat on the right. My truck also only has one of those rubber drain things in it, on the passenger side. The driver's side has the open hole for it, but nothing there. There is also a nice round 3/4" hole at the very bottom for drainage, making the rubber drain ports redundant. Once I got the water flowing from a hose into different parts of the cowl duct I first observed that the cowl is designed so that water flows from the right side to the left, with the exception of the last foot or so of the right (passenger) side. The only leaks I have found so far come from the vent ports, which surprised me. I examined the plastic vent assemblies, and they almost try to counter what they knew to be a point of entry for water, by extending a 'hood' from the back side of the vent into the cowl duct (sorry, no picture of this). But this feature is ineffective, as you can not expect a perfect seal between the vent assembly and the panel it attaches to. I'm not sure how I'll try and correct this. Possibly fabbing an aluminum flange and riveting it in place (with sealant as well) from the back side will keep water out. This was the case on both passenger and driver's sides. I also discovered a bad corner at the top of the cowl on the passenger side adjacent to a strange bracket that leaked, which will be easy to fix. No idea what the bracket is for, do you?

Tomorrow, as time allows, I'll start sealing up every seam I can with a combination of seam sealer and truck bed liner. I'll give it a week to cure up, and then test it again next Tuesday, which would be the next day I have off. I didn't see any problem with the windshield, but I'm tempted to have it taken off and redone-just to be sure. Lastly, I roughed up the 'gutters' at the top of the cab above the doors, and will run a new bead of sealant there as well. I have read it would likely be responsible for the water that appeared to be tracking under the weather stripping and has rusted away the edge the weather stripping sits on at the bottom of the door on the passenger side.

Any other suggestions? I'll do the best I can without making a career of it!

Rick

 

I too had resealed my cowl this spring, but didn't eliminate my leak.
A few weeks back I pulled my whole dashboard out to try and fine a short in the wiring and noticed daylight at the bottom of the windshield.
You could see the trail of the water in the dust.
It was traveling across the flange and dripping right in front of the high beam switch.
I used some 3M clear auto sealer from the inside once I cleaned the area up.

Realize that my '87 may differ from your '85 truck but it's worth a look

 

The cowl areas are pretty much the same from 80 to 96. Its best to remove all that bad seam sealer 1st, then use some rust treatment to convert what rust there is into a primer(forgot the name of it). Scuff of the paint in the cowl area for the bed liner paint to have something to grab on to. Layer up the liner paint too as it will fill in cracks and small holes.

I done this with my 89 F250 5 years ago and have no more leaks execpt where the AC box and brake booster mounts to the fire wall(stupid gaskets, should of replaced them when I had them off the firewall)

 

I used a self leveling urethane intended for sidewalk joints and such.
That stuff is messy but I think my cowl is tight.

Please let us know how it works out for you.

 

If you go look in the "stickys" for this forum there is a thread on cowl resealing with pretty good pictures and some notes as to where the leaks are generally located. Suggestion for you, one of the issues with the 80-86 cowl is the large slots in the cover panel, these let leaves and other debris fall in through them. Put a piece of screen under the panel. 87-96/7 have small holes which eliminates the problem.

BTW, pictures aren't that bad.

 

The '87 and up polka dot cowl retrofits and might be a better option in snow country.

 

Jim, FWIW, 87-91 fits, 92-96/7 is flat all the way across and won't retrofit.

 

Good to know.
Thanks Bill!

 

We found it out the hard way, picked up a nice one at P&P and when the guy who got it tried it on his 85 he found it wouldn't fit. He liked the dual windshield squirters.

 

Me too for my 89 truck, I wanted the better duel washer nozzles . So I swapped the cowl from a 92 (now parts)truck I have. Was not too happy finding out the cowls are diffrent.... So I made duel washer nozzles fit my 89's cowl!

I will install the duel nozzles in my 84's cowl once I get it running.

 

You can aim the squirters of the '87 cowl with a needle or other pointy tool.
They are swivel in socket style.

 

But they don't cover the windshield like the newer duel ones do. BIG time improvement for Florida's love bug season where you will use up a gallon of wiper juice to get those nasty things off!

 

Thankfully we don't have those up here.

I have ridden my motorcycle through swarms of those things before though.
That was NASTY!