I noticed the other day that when it rains I get water leaking into the cab of my 1976 D100 from behind the heater box on the firewall. Is there a known problem point for water leaks on these trucks? Or should I just plan on replacing the gaskets on the heater box and replacing the windshield gasket?

Thanks!

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Casually looking for a Clifford hyperpak intake for cheap.

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1964 Dart GT

Uh oh, is that a confirmation of my plan?

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Casually looking for a Clifford hyperpak intake for cheap.

Be very careful pulling apart the heater box for I dont think they make a replacement seal for it. But I would think its the window leaking more than the heater.

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~Nic

Rough welds in the corners where the A-pillar attaches to the cowl were a problem on my '73. I had leaks in both corners that were obvious when the seal was removed. One corner leak was visible from inside the truck, but the other side ran down behind the dash and into the upper edge of the carpet.

When I replaced the windshield I ground off the sharp welds and made sure there was adequate sealer when the new windshield was installed. No problems since.

it was ez to remake all the external and internal heater box seals using the existing seals as templates and purchasing replacement high or low density foam from one of the many internet foam suppliers. If I remember right, the heater box connections to the external defroster, AC and heater ducts were low density foam, like speaker grill foam. The internal seals, case top to bottom and internal doors were high density, like thin neoprene.
I used 3M spray adhesive to secure the foam seals.

and if you are going to replace the windshield seal, that would be the perfect to coordinate in any under dash ( heater box ) renews,, on my 83 D150, the screws that secure the top of the dash cover are under the windshield seal.

THanks guys. I guess I need to plan for a time when I basically disassemble the cab to a shell to clean up any rust and stop any water leaks. I need to replace my windshield anyway since it has 3-4 inches of fog from delaminating around the edges and I am going to replace the windshield gasket and lockstrip at the same time.

A few years ago I replaced all the foam seals in the heater system in my brother's 83 Dodge van with the high density stick-on foam weatherstrip from Home Depot. It has held up and worked great and realy cut down on cab noise and drafts.

If I had known when I purchased this truck what I know now about this truck, ik would definitely have paid a much lower price. It is all in once piece and runs and drives, but basially EVERYTHING needs attention. I think it sat under a carport for years and got dried out and baked by the sun. That's OK, though. It is mostly rust free.

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Casually looking for a Clifford hyperpak intake for cheap.

Yes Reed, just a confirmation. I had a 72 Dodge PU years ago(not a Slant), I made the Heater Box gaskets out of Laminate Floor Padding and used 3M spray as DadTruck suggested. The flooring pad is Very Firm Foam and waterproof. I replaced the windshield seal, and then replaced it again after I smashed the windshield a week later! and I did also grind the sharp edges as 64 Convert mentioned. At the same time I replaced the firewall seals/gaskets and the Truck was fairly water tight.

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1964 Dart GT

Water leaks are a funny thing. When I rebuilt my 85 P/U and had the truck painted, I replaced the windshield. When the gentleman came to install the new one he said I do not put any sealer on the new rubber. I was pretty hesitant about it, but my paint guy said he is good and you can trust him. Plus he said if it ever starts leaking just give me a call and I will seal it for free. After the truck was back on the road I took it through the high pressure automatic car wash (At least 3 times) and never so much as had a drop of water came in around the windshield. Guess he knew what he was talking about.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Yikes. Ok, I will plan on doing a thorough regasketing of the cab and cleanup of sharp edges. One thing I can't have here in western Washington State is water leaks into the cab.

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Casually looking for a Clifford hyperpak intake for cheap.

I'm watching this thread as I have the same problem on the driver's side. I vacuumed about a pound of leaves and acorns out of the cowl area hoping that would help.

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If it was easy, everybody would be doing it.

Don't hold your breath! We have entered the hot and dry season now so this isn't a priority. Plus fixinf a minor water leak on my work truck isn't anywhere near the top of my to-do list. At some point this year I will likely get to this, but it probably won't be for a while.

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Casually looking for a Clifford hyperpak intake for cheap.