1961-1966 F series Rust Prevention

Clean out those orifices!

Finding and cleaning the drain holes for cab mounts, cab corners, floor pans and fenders.

Anyone who owns one of these trucks knows that the most expensive and difficult repairs involve rust. "Slicks" were not built with galvanized metal, and rust prevention at the factory wasn't even a thought. Ford engineers did, however, design in some drainage to keep water from collecting in pockets but they are only effective if they are not clogged with debris. Well, any truck that has been on the road for more than a year is going to have debris issues. Depending on the area of the country where your truck was used it may be far worse than others. My truck is a pretty solid example from eastern North Carolina. It was obviously well cared for most of it's life and may have even been kept indoors to some extent. But, while doing some recent service work under the truck I began poking around at some of the factory water drains and common rust areas and found that even my truck was all too full of sand, pebbles, dirt and other stuff that would conspire to catch moisture and rust things out from the inside. This is an area of regular maintenance that is overlooked by nearly everyone. As I started to dig, I was appalled at the amount of crud I was able to extricate. This will now become a regular part of under vehicle service and I encourage you to do the same. Kept after, it shouldn't be that bad. The first time, however, creates a real mess!

My truck is a 1965 model. The 1966 cab is identical. I'm not sure if the 61-64 regular cabs are exactly the same, but they should have similar points to look for. Unibody trucks are another animal entirely, but again, they will have similar design elements. If I can get pictures of the undersides of some other trucks I will include them at a later date.

One of the most notorious areas for rot is the rear cab crossmember. This is a U shaped channel that goes from one side of the rear floorpan to the other. The outer extremities are known for rotting out. While patch pieces are available, avoiding the need to have them in the first place is far better. So, let's have a look.

This is the rear crossmember 'outrigger'. This is what yours should look like. Though I bent the lip of my inner rocker down a bit to facilitate cleaning, you should have an opening at the bottom like this. If you don't, what you're looking at is 40+ years of crud filling that up. Though not clear in this pic, at the top there is a gap between the floopan and the outrigger. You may be able to stick a finger in there and have a feel. Don't be too surprised if you can feel the crud level just inside the top! The crud acts as a giant sponge to hold moisture and rot this piece from the inside out. This photo is facing towards the rear of the truck, so that top opening is facing the front (there is a similar opening on the backside). Now, have a look forward at your front tire. Guess where it's aimed? Right at that stupid opening, which explains the crud lodged therein. The escape hatch at the bottom works fine for water and small bits of crud, but once you start tossing mud and small stones in there it's Game Over. For future prevention I'd seriously consider welding a piece over the forward facing opening to prevent entry of most of the debris.

The bottom could be improved upon as well by enlarging the opening, but I also think cutting out or bending the inner rocker flange out of the way would be another good idea. Not as necessary if you choose to block the upper opening though.

So, how to clean it? Well, let me tell you...it's gonna make a mess. Get some safety goggles, not just glasses. Get some compressed air, a few flat bladed screwdrivers and a nice dead blow hammer that won't mark the metal. Poke the screwdriver in there to break things up and use the hammer to help it find it's way out. The most effective tool, however, is the compressed air source with a blow gun tip.

The size of the upper orifice will vary, depending on the mood of the assembly line worker who welded it. The smaller your tip, the better. This is the passenger side of mine, facing towards the rear. Notice the big chunk of rock coming out the bottom. He and his 497 little buddies weren't too excited about leaving. I found that alternating blowing both in the top and up from the bottom will get most of them. You will find that some are just stubborn and are often too large to fit through the opening in the bottom. An old flat blade screwdriver and a hammer will usually break them into smaller pieces you can then get out the bottom. Blow, poke, whack. Repeat. This is not a 5 minute process. I bet I spent at least 30 minutes per side if not more until I got everything out.

At this stage, your garage floor will look like you've been operating a stone quarry, sandblaster or repairing bulldozers depending on the locale of your crud accumulation. You will be amazed how much crap you'll get out. It will go absolutely everywhere too, so if you're smarter than I, you'll do this outside.

Once cleaned out, you can debate if you want to spray anything in there as a rust preventative. I'm torn on this. Rust has undoubtedly started to some degree so it's too late to totally prevent it. Will coating over it help? Will spraying some kind of oily preventative help, or will it just give something for the crud to stick to and make futuer cleanings a PITA? I leave the answer up to you. I chose to do nothing, for now.

At the very back of the cab there are drains for the cab back panel. Rust here is pretty much invisible unless you are under the truck, so it often gets ignored. I found mine was starting to bubble.

I cleaned mine out as shown, and bent the flanges open a little further as well. These are not really accessible from inside the cab if you still have the fuel tank in there, so the compressed air simply gets blown upward. Now, understand that you will be blasting all the dirt up into the cab if you do this. There didn't seem to be much in these, but everything did get a nice coating of dust. Not bad to clean up, but something to be aware of. These don't really get road debris in them, just accumulated gunk from inside the cab.

While you're back here, have a look at the underside of the bed at the front. This is another common rot area. My truck came with holes drilled across the front for drainage of the bed, which really seems to have done the trick for preventing it to rust along that seam. You may want to consider the same.

All right, let's roll our creeper back up to the front floorpan and cab mounts.

Removable cover plate just to the right of this text.

The front cab mounts...these things will keep you up at night worrying about them rotting. There are access plates in the front to reach the cab mount bolts. I'd suggest pulling them off and having a go inside there with the shop vac on occasion. These are either in good shape or they're not. If they aren't, you need to replace them. Weakened ones will allow the cab to sag forward, playing havoc with the column shifter among other things.

The floorpan has some rearward facing drains, 3 per side as shown here with the air gun blasting them open in a reverse fashion. These are narrow openings and this is about the only thing that will work. I did not find that mine had much in them.

Also on 65-66 trucks (and others?) the bottom front of the door hinge area on the cab (the sloped part) is known as a pocket for rust. I'd say these usually go in combination with some other metal such as the cab mounts, but they may be worth a look. My truck has plastic plugs just above this area that you can take out and maybe snake a shop vac hose in there. There is no drainage for this area so not much else you can do about it. If your truck is rusted in this area (not shown), you can buy patch pieces of very high quality from Carolina Classics.

Another spot (not shown) I've seen problems with is the corners of the cowl, just above the fenders. If you have the fenders off, you may want to consider adding some drain holes in this spot as I've seen a few trucks rotting in this area. From what I can see it looks like a good water retention pocket.

The last of our 'service' areas is the fender bottoms. These are easy to miss, though I can't say I've seen many fenders rusted at the bottom because of the failure of this drain. But, it's there, so let's take care of it.

Up behind the fender there is a lot of odd spaces as well. When washing your truck a healthy blast of pressurized water back in there may help clean things out. When I pull the front clip off to replace my radiator support I'll take some pictures of what that all looks like, though there isn't much in the way of access to it.

Well, that's it for now. Hopefully this will aid in preventing future problems in your truck regardless of it being a nice original or even a restored version. Comments are always welcome to make these pages better.

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