Gentlemen,

Below is a picture of the firewall on a 1985 southern cab I just picked up this week. See the big hole directly above the hole for the clutch master? Can anybody tell me why someone would do that?...lol. It doesn't matter really, I'm going to fix it, but I'm curious why it was done in the first place. Any thoughts from the experts?

 

To make the truck lighter? Yea that's it make it lighter LOL.
or
"they said to drill a hole at the end of a crack to stop it from getting longer but no one said what size the hole had to be"
He did say free of rust holes but did you ask about drilled holes? LOL
Dave ----

 

Aftermarket AC? Any evidence of grommets?

 

It's right where the top bolt holding the CMC to the firewall would have been. Perhaps part of a custom firewall reinforcement attempt?

BB2

 

Could have been dealer AC, my dealer ac had holes drilled in the dog house portion on mine. But I don't think there was any specified location to drill.

part of me wants to get a hose crimper like we have at work and replace all my hoses and run bulkhead connectors through those holes.

Outside of that im curious do they have patch panels for these trucks outside of the cab corners?

I got a little rot in the area on the top of the heater opening on the firewall. I would consider removing my heater case again just to patch that properly.

 

I know, that's why it is so puzzling. It is in a strange spot. The cab was already stripped when I got it, so the original reason for the hole will remain a mystery I guess.

I'm just going to fill it back in, weld and grind smooth, and then drill a new upper hole.

 

The firewall looks to be in fair shape. Like the clutch was not being used or even in the rig. Maybe the cab was converted to an AT and the upper hole was then drilled for AC or other purpose? We'll likely never know.

Since you have it all open there, might as well weld in a real nice reinforcement plate for your clutch so you never need the "after thought reinforcement plate". You know, build it like it should have been done from the factory! You'll never have better access than now!

BB2

 

Actually, the cab has a home made solid tunnel cover installed, so yes, it was probably converted to auto at some point. Overall the cab is in pretty good condition. It is "southern", but that is all I know. Rockers and cab corners are original and not rusty, but there are some small holes in the floor pans...mostly the footwell area on the driver's side. Two spots of the roof need to be repaired...looks like it had a visor installed at some point. It has flash rust all over the place. The guy that had it did a bunch of sand blasting, primed it and then left it outside all winter. The cab mounds and underside of the floor look great.

There will be a hydraulic clutch going into this thing, so I will be repairing that area and reinforcing it one way or another.