Why Do We Have So Many Front Cowl and Trunk Waterleaks?

[Rusty34]

I have bought several Plymouth and Dodge B-Body cars over the years and they usually have water leaking down behind both Left and Right kickpanels soaking the front carpets and leaking into the trunk on both sides. Water streams down over the backs of the wheel wells and puddles on the trunk floor? This is on cars that do not appear to have rust around the windshield or back glass. Anybody have the answer to what needs fixing for this?

 

[dadsbee]

Because the lower cowl rots out from car sitting outside and the drain holes being clogged with eaves, crap and mouse nests..

 

[1967coronet]

And back glass bottom channel rust out in the corners .

 

[RemCharger]

There's so many different ways.. but zero trees would eliminate 99 % of them

 

[1 Wild R/T]

And it's not a problem that's unique to old Mopars... I know guys with Chevies & Fords, along with practically every other companies 50+ year old cars that have been attacked by the tin worm....

 

[493 Mike]

All cars, even today, are a product constructed to sell and "make money". Don't you think a pickup truck box could be designed to not rust out around the fender opening?
Mike

 

[YY1]

Vinyl tops contribute significantly.

...but the design of the rear window is mostly to blame as it holds water you can't see for a LONG time.

Raising the rear of the car makes it worse.

...and a vinyl top makes sure it stays moist long after the pooled water has drained or evaporated.

 

[Darter6]

Car companies would not survive if they built 'um to last.
But you are right Mopar's leaked when new. At the dealership we were told to drill holes in the F body cars trunk to let the water out back in 1976.

 

[Rusty34]

I would like to find a way to fix these if possible. Right now if the cars get wet I've been pulling the carpet out from under the kick panels to put towels in place and inside the trunk on both sides.

 

[YY1]

That's a bitch repair unless you are a seasoned body repair person.

Drill out about 200 spot welds, melt out the lead seams, etc.

...and replacement panels are either hard to find or non-existent.

I passed on MANY 71-74 cars because of cowl and hinge panel rust.

 

[gkent]

I learned long ago when washing my 69 RR ... once I'd dried the car I'd take the chamois and poke a corner of it into the rear window corner and lay the chamois out on the deck. The water would wick out in no time. Then do the other side.

I didn't have a problem with the cowl but I know why some would.

 

[YY1]

It's REAL hard to get paint in the cowl area, too.

 

[eldubb440]

8 years, 100,000 miles was all they were designed for

 

[Dave6T4]

I think the front windshield gasket was engineered TO leak on '66-'67 B-bodies. 1964 B-bodies had insufficient cowl drain on the the driver side. I think they fixed this by 1965, so they were not quite as bad.
While having my 1967 R/T repainted a few years ago, we discovered some rust under the trunk mat that had to be repaired. Water was somehow making its way into the trunk compartment, unnoticed, and was just laying under the trunk mat. My body guy said that when an old car gets restored and reassembled, sometimes they are no longer as weather-tight as the factory did it. He said, for this reason, he never washes his own old cars with a garden hose, but used the spray quick detailers instead. Our old cars never really get all that dirty, anyways.

 

[WileE]

8 years, 100,000 miles was all they were designed for

... and THAT'S a stretch ... a common source in the front are the windshield wiper pivot seals. In the back, another source is the trunk lid weatherstrip not sealing on the top side

 

[493 Mike]

When I repaired the cowl on my 65 Belvedere I completely removed the panel to weld in the inner and outer patch panels. When it was assembly time I used weld thru primer on the under side of the outer panel and completely covered the top of the inner panel with fiberglass mat and resin, filling the drain openings (oval holes) to the lip on the outer skin-so they could drain. I then brush painted black Rustolem paint on the fiberglass and everywhere I could reach.
Mike

 

[eldubb440]

on my buddy's challenger, similar to 71-up B's I believe; I used panel bond along the seam to attach where the upper cowl meets the firewall........ it also serves as a nice corrosion resistant seal to prevent any future rust stains

 

[68BabyBlue]

I learned long ago when washing my 69 RR ... once I'd dried the car I'd take the chamois and poke a corner of it into the rear window corner and lay the chamois out on the deck. The water would wick out in no time. Then do the other side.

I didn't have a problem with the cowl but I know why some would.

When I ran my 1970 GTX on the street in the late 70s, I replaced the trunk mat with newspaper, and changed it any time the car was exposed to water. I also blew the window channel out with a hair dryer. My friend Bob, who sold me Baby Blue a few years later, did the same. He went further, and managed to seal off the factory leaks in the rear window, and tail light housings. Baby Blue still has a near perfect original trunk floor and rear window channel. I can't speak for my '70, it's been off the radar since 1990.

 

[eldubb440]

the majority of 66-70s need this

 

[Darter6]

8 years, 100,000 miles was all they were designed for

Well in southwest Pa we were replacing fenders on cars that were 2 years old.
Yes look under the dash and you will find no paint midway up.most cowl panels never saw paint on the inside.
Rear windows corners of the early B cars had drain holes that dripped into the trunk,down the wheel house and were supposed to drain out the holes in the quarter panels. Rust in the lowers. That's why you find many of these cars have had patch panels put in because of clogged drain holes.