Found rust under the cowl. How bad is it?

[jtinpdx]

Hi All,
I've got a solid survivor 71 c10 LWB. Everything's really straight and the rust seemed contained to the kickpanel and rockers, which I realize is common. But today I took the cowl off to clean out some pine needles and found some rust on the cab below the windshield. Looks like there's a panel seem there?

How bad are these spots for a professional to fix? I've been thinking about getting the rust sorted and the truck painted. But I don't want to sink too much money into it. Would love to get your thoughts.

Thanks,
Jeff

[In The Ten Ring]

I am new to this sort of thing but I do know that what you see is not all there is. My cab is so far gone and so heavily bondo'ed up that I just decided to get a whole new (to me) cab and go for a swap. Someone will chime in that is actually experienced with what you have.

[hugger6933]

What has happened there is really common a problem all have had or will have sometime. What has happened there is the seam sealer has dried out and fallen out of place at some time down the road that appears to be a surface type that can be cleaned really easily and then protected with a primer then sealer reapplied to the area. Once that is done you should be able to forget about it. The 71 one ton i bought I thought was pretty clean just needs rockers [that is really good for us right now] and I too wanted to clean out the leaves as it was packed in under there so I took mine off and it was the same as your. I did what I said needed to be done then placed the sealer in that area. See I think part of the problem was that little "pool"area they made [little square spot] it should have been different or at least filled with sealer to help prevent that problem from occurring in the first place. What we are faced with is the truck makers NEVER planned on the truck having the following it does or that they would last this long. Jim

[57taskforce]

It probably hasn't been that way too long(decades) or the front floors would be rusted out. The water runs thru that Seam then either drips off the inside of the dash/ inside of the cowl or runs down the firewall. Either way it rusts the floor over time.still Looks pretty like a pretty easy fix like Jim said.

[litew8]

Everyone likes pics. Like Jim said, you can do a quick/dirty clean up. You won't see it with the cover on.








This was wire brushed more than shown

[jjzepplin]

What do you do if it has rusted all the way through?

[litew8]

Patch it I'd guess.

[jtinpdx]

Thanks for the feedback, guys. I'll look to wire brush out the rust and get some rust stop and sealant on there. Appreciate the help!

-Jeff

[jtinpdx]

One more question. Any recommendations on sealant and rust stop?

[litew8]

I've never used a rust stop. That's 3M "08308 Heavy Bodied" seam sealer in my pic. It worked out ok. Prob. not the cheapest. Check out my build link below for more pictures of prep etc...

[sboris]

That seam does not stop there. While all great tips, if your doing this, you need to look a little further. Stand on your head with a bright light and shine it straight above your fuse block and check out your seam from there. These repairs as litew8 said will be hidden. But nessesary if its bad. Check the pass side also. Hope your lucky, and as others have said, will be an easy fix . Just didnt want you overlooking something that will ruin all your hard work later.

[Metaldoc]

I had to replace the whole kick panel, vent , and cowl bottom. It spread like a plague so I would look deep.

[jjzepplin]

Nice!

[Longhornss]

Originally Posted by Metaldoc

I had to replace the whole kick panel, vent , and cowl bottom. It spread like a plague so I would look deep.

Metaldoc this is the exact repair I am undertaking in the exact same way. Only difference I am planning on eventually running vintage air so I am replacing the cowl vents with 5.25" speaker pods to eliminate the hastle of kick panel or door speakers.

That is some nice Work and great advice about looking above the fuse panel. You may have to move some of the cowl pad to see the seam where the upper and side cowl overlap. The general lapped a larg amount of metal here. Unfortunately the sealer breaks down an holds the water in the seam, rotting it away. From my experience the passenger side will be worse if you have rot in this area.

[Longhornss]

Here is the passenger side of my repair all welded up just needs grinding


The driver side cowl vent is gone, I am building a pocket for some new speakers, I will not be needing the vents.


This is the rusted area I removed from the inner cowl, as you can see the rust was significant even though the rust in the seam above it was minimal.






Here is a Shot of the speaker Pocket that will be welded into the cowl


If you cant tell from the pictures I have eliminated the lap welded seams wherever it was possible, and created butt joints. this will help reduce the areas where water can sit and rust out my cab again.

[Metaldoc]

I kept my vents and have the vintage sure fit going in. If ya don't get all the rust out, it will haunt you

[jtinpdx]

Really impressive work guys. I wish I had the expertise, tools, and shop to do what you're done. I'd even settle for a shop that wants to do the work for me. I can't even find that. I'm worried that I'm stuck with the rust that I've got and that it'll get worse.

-Jeff

[Longhornss]

Jeff,

Metal Doc and I may be scaring you a little bit. Your window rust did not seam all that heavy.

Again the first thing I would do is check behind the cowl padding above the fuse panel. You will see the overlapped seam up there. this is where a lot of water can come in and rot your rockers and floors. If you cant tell if it is leaking here, run the garden hose in there with the pad moved out of the way.

If their is water coming in determine the your damage state then. and remember check both Sides driver and above the heater box.

[sboris]

Originally Posted by jtinpdx

Really impressive work guys. I wish I had the expertise, tools, and shop to do what you're done. I'd even settle for a shop that wants to do the work for me. I can't even find that. I'm worried that I'm stuck with the rust that I've got and that it'll get worse.

-Jeff

Yeah, really good work. But might not be necessary. Dont panic till you scope it out like i said. Just wanted to point out worse case scenario. Check both sides, check antenna lead too. Could still end up that easy fix.. Good luck

[Metaldoc]

So much easier to fix now, and no, I don't want to scare ya. Take the time to do it right.

[litew8]

Yeah, the OP's doesn't look like an extreme case. Mine, it wasn't too bad - and since we were stripping the whole thing anyway, we tried to a decent job (which entailed more work) to help slow the rust down. You'll never be able to get into all the areas where rust might be, and if you're not looking to do a complete rebuild - I wouldn't worry about it. These trucks take FOREVER to rust through. Look at mine - the worst areas looked bad, but after cleaned up just lots of pitting. Our trucks have some quality steel from the 70's. If you go the seam sealer route, for 3M product I showed, you'll need a special gun.











Overlapping metal along the top (now seam sealed) is how water
runs down/in and rust forms (left/right windshield top drip rail).
Unfortunately, these are exposed/visible. e.g. No concealing with a cover.
Idk, but maybe GM designed these to be drains?

[jtinpdx]

Appreciate it, guys. I'll take a good look around when I get a chance. And if I can I'll take more pics.

-Jeff

[jtinpdx]

Gents,
I wanted to take a minute to follow up with you all. I've followed your much appreciated advice and have gone the seam sealer route. Not as pretty of a job as the pics posted above, but hopefully effective. Take a look. I went with the 3M heavy bodied seam sealer suggested and bought the gun for it too. Worth the cost if it works.

Thanks for all of your help! Now onto getting the kick panels patched where this water rotted them out.

-Jeff