ramses Posted April 16, 2020 Share Posted April 16, 2020 Working on an 86 F350 single cab with a lot of water intrusion. The cowl trough has severe corrosion from one end to another. In one area the gap is about 1-inch, but most is about 1/4-inch gap. Photo shows the worst spot almost directly on top of the gas pedal. I understand seam sealer is used along this seam, but given that a lot of the metal is gone, Im trying to figure how to work around this. Use a high-solids seam sealer on the smaller gaps? Still wondering how to tackle the large gaps... Link to comment Share on other sites More sharing options...
FuzzFace2 Posted April 16, 2020 Share Posted April 16, 2020 Seam sealer will not work on what you have going on there. You need to cut out the rusted parts and either weld or glue (panel bond) new metal in place to fill the gaps. Once the new metal is in place you then use the seam sealer to seal the seams so water cannot get between the 2 parts of metal and do this all over again. With the dash & wiring out you should have room to work from inside the cab to fix this. You can even do the seam sealer on the inside easy but its the out side that is going to be the hard part as you can only fit your hand / arm in so far thru the cowl openings. Some guys have that have only little pin holes after a good cleaning have use that spray sealer they show on TV. You know where they cut the bottom of the boat out and put in a door and spray it to seal it. I think they make a mat type sealer too so maybe after the clean up that may work but you really need to fill the gaps before you go sealing that area. Dave ---- Link to comment Share on other sites More sharing options...
ramses Posted April 16, 2020 Author Share Posted April 16, 2020 Seam sealer will not work on what you have going on there. You need to cut out the rusted parts and either weld or glue (panel bond) new metal in place to fill the gaps. Once the new metal is in place you then use the seam sealer to seal the seams so water cannot get between the 2 parts of metal and do this all over again. With the dash & wiring out you should have room to work from inside the cab to fix this. You can even do the seam sealer on the inside easy but its the out side that is going to be the hard part as you can only fit your hand / arm in so far thru the cowl openings. Some guys have that have only little pin holes after a good cleaning have use that spray sealer they show on TV. You know where they cut the bottom of the boat out and put in a door and spray it to seal it. I think they make a mat type sealer too so maybe after the clean up that may work but you really need to fill the gaps before you go sealing that area. Dave ---- Thanks Dave. I'll post the progress. Link to comment Share on other sites More sharing options...
kramttocs Posted April 17, 2020 Share Posted April 17, 2020 Thanks Dave. I'll post the progress. There is a lot of good photos on this over on FTE where a guy cut his all out and fabricated a seamless trough. To do it the 'right' way, yours needs cut out and replaced. Means pulling either the dash or the motor to really get at it. If this is just a use-it-up truck I would clean it real good, get some rust converter (few to choose from) and spray or brush it on as best you can. Then, like Dave also said, get some of the flex seal tape and tape over the holes. I would just run the tape along the whole trough. After that spray it liberally with the aerosol flex seal. It would last for a long time. Just depends upon your plans with the truck and what approach you want to take. Link to comment Share on other sites More sharing options...
ramses Posted April 17, 2020 Author Share Posted April 17, 2020 There is a lot of good photos on this over on FTE where a guy cut his all out and fabricated a seamless trough. To do it the 'right' way, yours needs cut out and replaced. Means pulling either the dash or the motor to really get at it. If this is just a use-it-up truck I would clean it real good, get some rust converter (few to choose from) and spray or brush it on as best you can. Then, like Dave also said, get some of the flex seal tape and tape over the holes. I would just run the tape along the whole trough. After that spray it liberally with the aerosol flex seal. It would last for a long time. Just depends upon your plans with the truck and what approach you want to take.To be honest this is a work truck so the idea of putting new sheet metal was the best optuon but would add a lot to the schedule. All I want is to stop the leaks. Had seen the flex tape and wondered if it could work. Thanks for the tip. Could the brush-on (flex liquid) work also? Get Outlook for Android From: kramttocs [via Bullnose Enthusiasts] <redacted_email_address>Sent: Thursday, April 16, 2020 9:47:28 PMTo: ramses <redacted_email_address>Subject: Re: Cowl Trough Corrosion There is a lot of good photos on this over on FTE where a guy cut his all out and fabricated a seamless trough. To do it the 'right' way, yours needs cut out and replaced. Means pulling either the dash or the motor to really get at it. If this is just a use-it-up truck I would clean it real good, get some rust converter (few to choose from) and spray or brush it on as best you can. Then, like Dave also said, get some of the flex seal tape and tape over the holes. I would just run the tape along the whole trough. After that spray it liberally with the aerosol flex seal. It would last for a long time. Just depends upon your plans with the truck and what approach you want to take.ScottDaily driver: 'Camano' 1986 F250 Supercab XLT Lariat 460/C6Work truck: 'Chanute' 1980 F350 C&C 400/T18 - Gin PoleVarious parts trucks If you reply to this email, your message will be added to the discussion below:http://forum.garysgaragemahal.com/Cowl-Trough-Corrosion-tp57028p57080.htmlTo unsubscribe from Cowl Trough Corrosion, click here.NAML Link to comment Share on other sites More sharing options...
Angelo Voltura Posted April 17, 2020 Share Posted April 17, 2020 No brush on, sealer, JB weld type stuff is going to fix that. It's gone. I'm sure if you really wanted to hack it you could get it to stop leaking, but it's going to be a bandaid and make it worse when it really gets bad. Do the sheet metal now while you are in there, or you going to be putting a cab on it because it'll rot the floors out. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted April 17, 2020 Share Posted April 17, 2020 I understand seam sealer is used along this seam, but given that a lot of the metal is gone, Im trying to figure how to work around this. Use a high-solids seam sealer on the smaller gaps? Still wondering how to tackle the large gaps... See what you have left once you get all the caulk and rust scraped out of there. If it's not too structurally deficient I'd be tempted to forget the rust converter and go with epoxy and fiberglass. But then, I'm an epoxy geek, and see using it many places. It's not as if it's a fender where the back side is seeing the water and mud thrown up off the road. You'd need to scour the glue into clean metal for a structural bond, and then working while it's just setting up, bridge the gap with some roving and probably lay some light cloth across the whole floor of the cowl from one side to the other. You'd end up with a continuous composite trough. It would never rust out if water can't get under any edges, that's why it's important to have it clean and scrub the epoxy into the entire surface before adding any reinforcement. Being in Puerto Rico you might find someone in a marina or boatyard to help you. There is fiberglass 'tape' in various widths. And it definitely needs to be epoxy not polyester. Link to comment Share on other sites More sharing options...
kramttocs Posted April 18, 2020 Share Posted April 18, 2020 I understand seam sealer is used along this seam, but given that a lot of the metal is gone, Im trying to figure how to work around this. Use a high-solids seam sealer on the smaller gaps? Still wondering how to tackle the large gaps... See what you have left once you get all the caulk and rust scraped out of there. If it's not too structurally deficient I'd be tempted to forget the rust converter and go with epoxy and fiberglass. But then, I'm an epoxy geek, and see using it many places. It's not as if it's a fender where the back side is seeing the water and mud thrown up off the road. You'd need to scour the glue into clean metal for a structural bond, and then working while it's just setting up, bridge the gap with some roving and probably lay some light cloth across the whole floor of the cowl from one side to the other. You'd end up with a continuous composite trough. It would never rust out if water can't get under any edges, that's why it's important to have it clean and scrub the epoxy into the entire surface before adding any reinforcement. Being in Puerto Rico you might find someone in a marina or boatyard to help you. There is fiberglass 'tape' in various widths. And it definitely needs to be epoxy not polyester. Jim - so even if the rust is still there (unconverted) the epoxy will stop it from spreading? Link to comment Share on other sites More sharing options...
FuzzFace2 Posted April 18, 2020 Share Posted April 18, 2020 Jim - so even if the rust is still there (unconverted) the epoxy will stop it from spreading? I would think the thinking is if you seal the rust from air & water, 2 things needed for rust to grow, it would stop it. Dave ---- Link to comment Share on other sites More sharing options...
kramttocs Posted April 18, 2020 Share Posted April 18, 2020 I would think the thinking is if you seal the rust from air & water, 2 things needed for rust to grow, it would stop it. Dave ---- That makes sense. Would the aerosol rubber/bedliner not do the same? Curious since I've never worked with epoxy/fiberglass. Link to comment Share on other sites More sharing options...
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