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Howdy y’all! So my 85 f150 has a cowl leak. I have the cowl removed I pulled up the rubber mat to let the floor boards dry. Obviously it’s been a issue with the truck as I found the cowl was full of old silicone and the floor boards someone has fiberglassed/bondo some areas.. Y’all I did try the search on forums but I was having a hard time finding a thread about it. One started off talking about the cowl than went way off subject… But I’m newer to the site! Anyway..
The photos don’t really show the rust spots.. it’s pretty dirty and there are more rust spots but it was hard for me to get in the photos.I’m also still working on removing the old silicone..
so what’s some ways I can fix it and stop the leak? Any help I can get y’all would be appreciated! Thanks! 😉
My trucks are just tools I use to get other work done, not a show truck. So as long as it seals it up, that is all I worry about. The few times I have had places like that, and needed to seal it up, I used roofing patch. The thick black tar you can get at the hardware store. It's waterproof and thick enough to cover over minor holes. And since you can't see this area, it's what I have used before to seal cowl leaks.
I dig all the old factory sealer out, and any other sealant like silicones out. The conventional silicone contains an acid that actually can aggravate the corrosion. Once you clean that all out really good, I used rustoleum rusty metal primer and coat the area really good to help stop the rust. Once that dries, I take a putty knife and a gallon of roofing cement (the thick black stuff) and slop that all over the bad areas, covering over the holes and bad spots, and also replacing the factory sealer that had gotten hard and fallen out. It seems to last a long time.
P.S. I would not use the roofing cement on the floor. A quick patch for that is rivet some metal on it, and then seal it, or more fiberglass mesh.
My trucks are just tools I use to get other work done, not a show truck. So as long as it seals it up, that is all I worry about. The few times I have had places like that, and needed to seal it up, I used roofing patch. The thick black tar you can get at the hardware store. It's waterproof and thick enough to cover over minor holes. And since you can't see this area, it's what I have used before to seal cowl leaks.
I dig all the old factory sealer out, and any other sealant like silicones out. The conventional silicone contains an acid that actually can aggravate the corrosion. Once you clean that all out really good, I used rustoleum rusty metal primer and coat the area really good to help stop the rust. Once that dries, I take a putty knife and a gallon of roofing cement (the thick black stuff) and slop that all over the bad areas, covering over the holes and bad spots, and also replacing the factory sealer that had gotten hard and fallen out. It seems to last a long time.
P.S. I would not use the roofing cement on the floor. A quick patch for that is rivet some metal on it, and then seal it, or more fiberglass mesh.
Thank you, I appreciate your response!! Man, I wish it was a show truck but it ain’t ever gonna be, it’s just my daily driver… But I love my 85. Hopefully tomorrow when I finish cleaning it out, it wont be any worse than what I’m seeing so far. 😂 I was expecting it to be totally rusted out. Luckily the previous owner did screen the cowl so there’s no trash in it. Well besides the loads of silicone!
I will pick some of that tar up tomorrow and hopefully get it sealed up! I agree, as long as it seals up that’s all I care about!! It ain’t gotta be pretty!
After that gonna look at the floor boards and see what I can do, I like the idea about riveting metal. Could be better but could be a lot worse. Next project to tackle after the cowl. Least it’s finally getting to dry out.
Haha going off topic ain’t bad, I actually enjoy reading the threads! There’s a lot of knowledgeable members on this site and I really like their input! I was a little hesitant posting about the cowl leak as it is has been discussed I’m sure a bunch! I have just seen threads go south because of new members posting about the same stuff that’s been discussed a bunch, when they could have used the search and got answers! So I tried search and I wasn’t getting but one thread, BUT I’m sure it was me not using it correctly.. As it was hard for me to even remember how to start a post! 😂 I just didn’t wanna post and make anybody mad because I really enjoy this forum it has helped me a lot!
Thanks for sharing the link! Really appreciate the the input! 😁
I dont know how large the rust holes are but I have seen it posted of using Flex Seal I think it is.
You know they use it on the bottom of a boat to seal it and then put it in the water. They also make it in a bucket you can spread it.
If you get the spray can and take a nozzle that you can uses that plastic straw that you always loose. Use that on the Flex Seal and yo ucan point the straw where you want it.
You will also want to look under the dash to see what rust thru holes you have.
You said you had a screen on the cowl but I bet there is still a lot of dirt behind the kick panels.
You already have the rug / rubber mat up so just a little more work needed to pull off the kick panels.
It looks like you may have AC and if so when you pull the kick panels off there will be a metal panel held on with 4 screws.
Pull the metal panels off and clean out below the opening.
There should be a drain in there and because of the dirt water cant drain and before you know it you have rust.
BTW if you can find non-AC kick panels you can use them and just dont put the metal plates back in place.
You now have air flow from the kick panels. My truck was a non-AC truck so I kept the air flow panels but also added AC to my truck.
Dave ----
I dont know how large the rust holes are but I have seen it posted of using Flex Seal I think it is.
You know they use it on the bottom of a boat to seal it and then put it in the water. They also make it in a bucket you can spread it.
If you get the spray can and take a nozzle that you can uses that plastic straw that you always loose. Use that on the Flex Seal and yo ucan point the straw where you want it.
You will also want to look under the dash to see what rust thru holes you have.
You said you had a screen on the cowl but I bet there is still a lot of dirt behind the kick panels.
You already have the rug / rubber mat up so just a little more work needed to pull off the kick panels.
It looks like you may have AC and if so when you pull the kick panels off there will be a metal panel held on with 4 screws.
Pull the metal panels off and clean out below the opening.
There should be a drain in there and because of the dirt water cant drain and before you know it you have rust.
BTW if you can find non-AC kick panels you can use them and just dont put the metal plates back in place.
You now have air flow from the kick panels. My truck was a non-AC truck so I kept the air flow panels but also added AC to my truck.
Dave ----
Looking outside the cowl I’m a little worried about how big the holes will be once I finish cleaning the old silicone out…. Especially towards the drivers side where all that rust is…
oh the truck used to have AC but it doesn’t now!
i did post some more pictures. Sorry for the short reply! I’m in and out while they install counter tops. So I haven’t really had a chance to read or remove the passenger side panel.
What you can expect to find behind the square panels Dave speaks of. In my truck's case, this was the primary source of water under the mat.
dang! Luckily I didn’t have all that.. but still rust in there! 😂 I did post some photos! Haven’t got a chance to mess with the truck to much, having counter tops installed so I’ve been in and out. I’ll be able to go back and read replies better in a few yall! Thank you for the help!
My local body shop used automotive structural adhesive to reseal my under cowl ditch. 3m makes a bunch of different types, cartridge, tapes and putty types for all sorts of body repairs and more. Search that solution if you are looking for something more than roof tar. It can be formed and painted as needed. Worth a look but more $ than roofing tar.
My local body shop used automotive structural adhesive to reseal my under cowl ditch. 3m makes a bunch of different types, cartridge, tapes and putty types for all sorts of body repairs and more. Search that solution if you are looking for something more than roof tar. It can be formed and painted as needed. Worth a look but more $ than roofing tar.
I will check that out! Thanks! Have you or anyone you know used 3m for cowl repair and it hold up alright?
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