So...cowl repair. Need advice - Vintage Mustang Forums
 12Likes
Reply
 
Thread Tools
post #1 of 38 (permalink) Old 06-26-2019, 11:00 AM Thread Starter
Senior Member
 
wicked93gs's Avatar
 
Join Date: Feb 2009
Location: Nashville TN
Posts: 399
So...cowl repair. Need advice

I would like to preface this by saying I dont know how bad the driver's-side cowl is yet, have to pull that vent...but when I got the car that floor board was pretty badly rotted and I dont see much other source. I just finished replacing the floors driver and passenger(and lower angled portion of the firewall...floorpan extensions) due to rot on those pieces. So today I crawled under the dash on the passenger side and to my confusion the only rust I see around that vent is light surface rust on the underside(I suppose its possible that a heater core leak caused the rot on that side). With the driver side vent in place...I dont see any rot(again just surface rust) on the metal around it...but I do see darker rust peeking out from under the vent, so I assume that at the very least that collar is shot...which means that the cowl has to come off for at least minor repair which leads me to my question:

Should I:

A. Just buy a couple of patch panels and go that route?

B. Buy a lower cowl assembly and replace the lower cowl?

C. Buy the full upper and lower cowl and replace the whole thing?

From everything I have seen the Dynacorn assembly fits very well and I am not particularly worried about being able to fit the thing...its just that I dont want to ever have to repair the cowl again after this one time. Keep in mind that this car WILL be a daily driver for probably 200+ days a year...even though most of the time I will have a cowl cover on the thing anyway since I dont see the vents as particularly useful most of the time anyway.
wicked93gs is online now  
Sponsored Links
Advertisement
 
post #2 of 38 (permalink) Old 06-26-2019, 11:06 AM
Senior Member
 
DaleB's Avatar
 
Join Date: Feb 2019
Location: Omaha, NE
Posts: 182
Garage
First off, make sure you kow what's rusted and what's not. I assumed my cowl would be rusted out, at least the collars, since the floor pans had been replaced and there's a hole in the passenger side firewall extension. Turns out, the cowl and collars are just fine!! No rust holes at all, nice and solid. The heater hoses had been leaking. You can inspect almost 100% of the collars and cowl from below and the sides, if you have your fenders off. There are access holes, and a good flashlight helps. A video borescope helps even more.

So, if you need a collar repair set (plastic collars that get bonded in from inside the car), let me know, I have a set I won't need.
Huntingky and BlakeTX like this.
DaleB is offline  
post #3 of 38 (permalink) Old 06-26-2019, 12:34 PM
Senior Member
 
Magnus's Avatar
 
Join Date: Aug 2002
Location: Brandon, Florida
Posts: 1,199
Garage
If you look up in the hole there look closely at the seam where the vertical pipe meets the cowl floor.

There's some seam sealer there that rots out and lets water seep through. If you run a hose on the cowl for a while you might see it getting damp. It'll take a few minutes since it's just seeping water instead of pouring through a hole, but that could be your problem and it's worth looking at before you start cutting things up.

Just one more thing to look at.
1ofAMillion+ likes this.
Magnus is online now  
 
post #4 of 38 (permalink) Old 06-26-2019, 01:50 PM
Senior Member
 
Join Date: Jul 2013
Posts: 4,020
I guess the windshield frame isn't mentioned enough as a leak spot. THE WINDSHIELD SURROUND CAN RUST AND LEAK Even leak without an extraneous hole then a hero squirts silicone around the seal and makes it worse. Top or bottom lengths can hold water when not driven.
After that spot is where the inner cowl meets the kick panel wall, it is spot welded and seem sealed. The sealer can fail and leak without making any actual new holes.

Some if not most can be repaired and treated to last another 50 years without major surgery. Search for Cowl Repair Hats and pick a seem sealer.

Verbose Vocabularian
1ofAMillion+ is online now  
post #5 of 38 (permalink) Old 06-26-2019, 02:45 PM Thread Starter
Senior Member
 
wicked93gs's Avatar
 
Join Date: Feb 2009
Location: Nashville TN
Posts: 399
Well, I took the vent off and inspected the driver's side closer from underneath. There is no rot that I can see on the cowl panel itself...just minor surface rust(which tells me nothing about the other side of the panel, but the bottom side is good. As I suspected though, there is a lot of rust flaking from the cowl collar itself...I suspect its starting to rot. The main problem though is that I reached up into the collar and felt around and it seems like there about an inch or so of mulch from decomposing leaves and the like surrounding the collar holding moisture. So...I believe I can get away without any metal cowl repair at all...if I can somehow manage to remove all the mulch surrounding the collars and using one of those plastic collar repair kits...also keeping the cowl vent blocked off. Anyone have any tips on how to easily remove all the debris in there? My hands are large and while I may be able to grab a pinch at a time, that just doesn't seem like it will get it all. Its pretty damp so I doubt a vacuum will suck it up very well...but if I can find or make some sort of U shaped attachment I will try that method. Since I am sure that debris has been sitting there an causing surface rust and pitting on the top side of the panel, is there any way to get in there with a spray paint can and giving it some type of protective coat?

I just dont want to end up in a situation that the cowl will need repair AFTER I paint the car, so looking for the best path forward, even if that involves pulling off the upper cowl(only 200 spot welds right?)
wicked93gs is online now  
post #6 of 38 (permalink) Old 06-26-2019, 02:52 PM
Senior Member
 
Woodchuck's Avatar
 
Join Date: Mar 2001
Location: Peoples Republic of Vermont
Posts: 32,685
Send a message via Yahoo to Woodchuck
Try a piece of PVC drain trap for the "U" shaped piece for your vacuum. I think what you'll find, though, are pinholes all along the "hat"....
vegasloki likes this.

Bart

What, me worry?
- Alfred E. Neuman

Woodchuck is offline  
post #7 of 38 (permalink) Old 06-26-2019, 03:00 PM Thread Starter
Senior Member
 
wicked93gs's Avatar
 
Join Date: Feb 2009
Location: Nashville TN
Posts: 399
Quote:
Originally Posted by Woodchuck View Post
Try a piece of PVC drain trap for the "U" shaped piece for your vacuum. I think what you'll find, though, are pinholes all along the "hat"....
You are probably right....best to pull the upper cowl and just patch the lower(or the collars, at the least) and be done with it...which leads back to the question of patch or replace...worried about having enough room for my MIG(or TIG, whichever method I choose to use there) torch inside the cowl to get a good bead laid down.(There might be plenty of room for all I know, but it seems pretty tight looking at it)

P.S. What kind of time am I looking out for a cowl repair without major rust?

Last edited by wicked93gs; 06-26-2019 at 03:04 PM.
wicked93gs is online now  
post #8 of 38 (permalink) Old 06-26-2019, 03:04 PM
Senior Member
 
Join Date: Apr 2014
Posts: 520
you can cut into the top cowl piece near the drain on both sides and bend it up like a door to get you close. I did this on both sides, got a 1/4" threaded rod with a small wire brush on it and was able to get off the surface rust, cleaned it up, coated with rust encapsolator, seam sealed, applied undercoating with a gun with long nozzle, then for good measure glued in the plastic hats. Then welded my "door" back in and opened up the drain to lessen the chances of crap getting stuck in there.


If you open it up like this you will know the exact condition of what you got.
Jedi is offline  
post #9 of 38 (permalink) Old 06-26-2019, 03:25 PM
Senior Member
 
DaleB's Avatar
 
Join Date: Feb 2019
Location: Omaha, NE
Posts: 182
Garage
I too found a pretty good collection of pine needles and leaf debris in there. I was able to get mine cleaned out without surgery.

There's a rubber plug in a round hole; that provides an extra path into the area in addition to the drain opening. I was able to poke in there with a dowel and various other implements to loosen the material, and vacuum it out. A few shots of compressed air along the way helped also. When I was done, I found sound metal with light surface rust -- certainly sound enough to not need to replace anything. My plan is to clean it all up as much as humanly possible, maybe even resorting to a little sand blasting if I can get in there. I have this little sandblast rig... it's just a sandblast gun with a siphon hose and pickup tube, you stick it in a bag or bucket of media and have at it. It's not good for much, but it will be plenty for this little area. Then coat with POR15 or similar product to stop the rust, then brush on seam sealer around the base of the hats.

Like I said, I got lucky -- there are no rust holes at all that I can find. The metal on the hats isn't even noticeably thin or badly pitted. If ONLY the quarter panels were in that condition!!
DaleB is offline  
post #10 of 38 (permalink) Old 06-26-2019, 03:36 PM
Senior Member
 
Join Date: Sep 2005
Location: NJ
Posts: 2,794
IMO, if you're car will be a DD and driven in the rain, bite the bullet: remove the cowl top so you have full access to weld in metal as needed, seal and paint. I welded my cowl hats 100% so I'm not just relying on seam sealer to stay leaf free. You may also uncover rust at in the cowl sides/weld flanges like mine had.

'65 A-code coupe, T-10 4-speed, 8" 3.25 limited slip
stephen_wilson is offline  
post #11 of 38 (permalink) Old 06-26-2019, 03:37 PM
rdnck1
Supporting Member
 
rdnck1's Avatar
 
Join Date: Oct 2018
Location: Orland Park, IL
Posts: 170
Garage
I had the same issue. Leak was extremely small but it was there. To get the crude out I used air then shined a light through the top vents and could see it shining through a couple places. See pic where the rust through was actually in the upper right hand side of the cowl. The seam sealant was also not great in several places and would be damp below when a water hose was used to check the cowl. I went ahead and replaced the whole cowl assembly not knowing how extensive the damage was. In hindsight, a partial replacement would have worked just as well if not better and had been easier. The old cowl wasn't as bad as I originally thought but now I'll be good for another 50 years. Good luck, Jim
Attached Images
File Type: jpg IMG_1323 (2).jpg (218.3 KB, 12 views)

Do your own research, I'm just a work in progress
rdnck1 is offline  
post #12 of 38 (permalink) Old 06-26-2019, 03:50 PM
Senior Member
 
Join Date: Nov 2018
Location: DFW
Posts: 241
Most will say to replace the whole thing and epoxy prime the inside of the new one...


Has anyone tried having a new lower cowl galvanized? That would be the way to go if you could find a shop that hot dips and it doesn't warp the panel during the process. The Dynacorn stuff is coated in a cold galvanizing that they call a weld through primer.
elcam84 is online now  
post #13 of 38 (permalink) Old 06-26-2019, 07:15 PM
Senior Member
 
Join Date: Jul 2013
Posts: 4,020
I think the cowl itself was one of the heavier galvanized pieces originally.
I was able to wiggle the stove pipes off of their spot welds and remove them. They are a lot thinner than the cowl itself and should come out without harming the surrounding metal. I also have hands larger than the President so those couple of inches gone will let you get your hand or a hose up in there easier to remove that mulch turned dirt. i think its only 3-4 bolts to remove the splash shield from behind the tire and you will see the corner cowl drain to make sure thats clear and also to not just push the crud from the cowl onto the back side of the fender.

Vacuum, leaf blower, air hoses and patients will get it good and clean. Then treat and coat to your delight.

Verbose Vocabularian
1ofAMillion+ is online now  
post #14 of 38 (permalink) Old 06-26-2019, 08:39 PM
Senior Member
 
Join Date: Sep 2012
Location: Fl
Posts: 1,733
If you can see rust and its leaking - just replace the lower. My upper ('66) was perfect, so my body guy just replaced the bottom. I had him prime and finish paint ALL inner surfaces of the cowl. That is not per the factory - but I don't want to ever have to deal with the cowl again - besides, who would want to see a '66 HiPo/automatic special ordered anyway? j/k, I used to show it sometimes in the '80's, but the snobbery was too much for me so I stayed on the 1/4 mile and SCCA tracks instead.
66kcar is offline  
post #15 of 38 (permalink) Old 06-26-2019, 10:37 PM
Senior Member
 
FrankieThe69Kid's Avatar
 
Join Date: Nov 2014
Location: Marshfield, MA, USA
Posts: 1,790
I'd do at least the bottom... I'd do the top as well because it doesn't cost much more than doing only the bottom, and it can be done using the original "spot weld" method. If you replace the bottom only, you'll be filling the holes you drilled in the top rather than a true spot weld. The cowl is structural. Do it once, do it right.
I didn't have the option of "either/or" on my 69. There's no patch kit available and the only cowl replacement was top and bottom, and I'm glad it was the only option.
I welded the bottom in, primed it and painted it, but masked off the lip so I'd get a clean weld when I did the top. Granted, Ford didn't paint the lower cowl, but you can't see it once the top is on.
Heck, you've got it apart anyway, and Dynacorn does a really nice job with the repro parts. Might as well do the whole thing.
Attached Images
File Type: jpg IMG_20150913_241157300_HDR.jpg (487.8 KB, 11 views)
File Type: jpg IMG_20160324_232157330_HDR.jpg (384.8 KB, 11 views)
File Type: jpg IMG_20160422_235833415_HDR.jpg (361.1 KB, 10 views)
Boss5Oh and vegasloki like this.

69 Convertible, 351W, T5, E-Brock Performer 351-W intake, Performer Plus cam, Holley 4160, power assist, dual exhaust, 4-wheel manual drums.
FrankieThe69Kid is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Vintage Mustang Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in













Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome