74 f100 360 auto 2wd. Been restoring as time allows over past 3 years. In prepping truck for a new master cylinder/booster replacement I decided it was time to uncover torn vinyl covered cab floor. Truck was a ranch truck (not registered for years) with only 100k miles. Spent mucho time cleaning everything but the cab floor when I purchased. Have been smelling fumes since day 1 so I expected some rust holes. Have some but not too bad. 3-4 small ones on driver and passenger side floors. Turned my attention to cleaning firewall area after removing old master cylinder/booster. Noticed some rust debris and followed it to the top of engine compartment firewall. Looks like the vent hole intakes in front of windshield has rusted through, all the way across the entire width. Clearly the screwdriver pushes through from the top into the engine bay but it also looks like the area also opens into the passenger compartment as well. Very hard to see given the location. Question--have others experienced this problem? and what was your solution? I don't know how you'd get access if you wanted the new metal proper fix. This truck's intake manifold has the typical oil leak problem and the fumes are getting to be too much. Could you seal this area from the firewall with some type of sealer? Still wouldn't help the water leaking from the windshield area vent holes and into the cab. Hymm. Got to be a reasonable solution other that disassembly of the entire truck. Sorrow for the length of post. Hope its clear enough. Very much appreciate your input. Thanks...

 

Can you open the pic with "paint" and point out the rust?

Part # 02010 is a galvanized top panel.

Here is a dash out shot or 2.

PM sent your way.

 

Sorry for my incompetence with posting detail photo, but it is the galvanized top panel shown in your blowup. When looking down the vent slots beneath the windshield there is a seam (corroded area) where it is apparently married to the firewall. One idea is to cut out slats beneath the window and put in a new piece of metal all the way across inside that area. Then reattach the slotted metal. This should stop water from entering the cab down the inside of the firewall. Then apply some type of sealer across the front of the firewall to seal off fumes getting inside of the cab. Unfortunately this truck has a non functioning a/c unit which makes it very difficult to seal the area above the unit on the firewall.

 

There are a few guys on here that replaced the complete cowl panel with one form a JY, just have to have a welder handy. You do know there are drain holes at each side where there is like a bucket? Maybe at the bottom of piece 02300?

To stop the fumes you might need a exhaust donut or get the end of the exhaust a little further back, at lest behind the cab back wall.

 

Thanks for your quick response. Please explain "with one form a JY". I don't understand. Did not know there were drain holes but that certainly is logical. The water has to go somewhere. I would have someone do the welding but I would have to tell them what to do.

It isn't so much the exhaust rather the fumes from the oil leaking out the back of the intake manifold.

 

A couple of FTE members have went to a JY "Junk Yard" and cut off the complete cowl assembly and grafted is to their truck.

I'd look up behind the plastic front fenderwell liners for the drain holes asccess.

Well pull the dizzy and intake and replace the gaskets. Do not be tricked in to using those dang rubber S gaskets at the front and back.... 1/2 bead off oil resistant silicone/RTV.