Frequently Asked Questions
1.)
a.) I need new fenders for my truck since mine are rusted, where should I look? Are they hard to change?
b.) My rockers and floors are a little rusty. What can I expect to find as far as the extent of the rust damage?
d.) Where can I find a new bed, since mine is rusted away?
e.) What tools and supplies will I need to do a proper job replacing parts and panels?
1.)
a.) You can get new fenders from many different places. Some are better quality than others. In 1992, the replacement parts industry began requiring that all replacement body parts be galvanized. All that I've seen in recent years are. JC Whitney, LMC truck, and others have replacement body parts, and repair panels. A very large selection actually. Some are even designed to replace parts of other sections as well. For instance, Inner Rocker panels. They make extended Inner Rocker panels. They have a larger lip where they meet the Cab Floor, since chances are the rust carries over onto the edge of the Cab Floor. This makes repairs easier, since you can weld the panel to solid metal, and all the rust can be cut off the edge of the Cab Floor from the start.
When replacing the Fenders, it's common to replace the Inner Fenders (Wheel Wells) as well. The Inner Fenders bolt to the inside of the Fenders. Where the two bolt together, is where most rusts starts on the Fenders. There's no sense in bolting a rusty Inner Fender to a brand new Fender. Using new bolts is a good idea too, when replacing Fenders. Why use rusty bolts to secure new rust free parts? You want to eliminate all the rust you can. Aftermarket Fenders run about $50, as do Inner Fenders.
When replacing the fenders, and Inner Fenders, you replace them as a unit. By that I mean you bolt the Inner Fender to the Fender, and then bolt them onto the truck as one piece. Even if just replacing the Fender, you would remove it with the Inner Fender attached, then separate the two off the vehicle. Then bolt the old Inner Fender up, and mount them on the truck. When they are not bolted to the Fenders, the Inner Fenders are not very rigid, they actually feel flimsy. After loosely bolting the Fenders on the truck, you can adjust them with shims. When you replace the Fenders, you may discover that your Radiator Support is rusted as well as your Front Valence, (the piece under the grille). The Battery tray is also usually rusted as well, and should be replaced, at about $10, it's cheap enough. The Radiator Support is a whole other project.
When replacing the Fender, there is a step by step process involved. It makes a difference which bolts you put in when, as far as making it easier, and getting the Fender aligned properly.
Notes:
* To remove a Fender, the Hood must be removed.
* To align a Fender, the Hood must be on.
* When replacing the passenger side Fender, the Battery Tray should be removed first.
*A Factory Service Manual contains instructions for changing body parts****
*Bare metal must be primed with a "Self Etching Primer" because 'regular' primer just doesn't bond well.
*Seams must be sealed with Seam Sealer. Failure to do so will result in premature rusting of new parts.
*Replacement body parts DO NOT come with Seam Sealer on them, you must buy it and put it on yourself.
b.) Floors & Rockers - A typical rust repair, where the rockers and cab corners are rusty usually involves many other parts as well. Here's a run down of what is commonly replaced at the same time, when repairing cab rust.
Cab Corners, Rocker Panels, Inner Rocker Panels, Cab Floor Supports, Cab Floor Channels, and the Floor Pans themselves.
Having these parts replaced at a shop will run as much as $2,000 in some areas, not including any paint other than Primer/Sealer.
Along with these parts, there are others that might be rusted, such as Doors, Front Fenders, Front Inner Fenders (Wheel Wells), Hoods, Radiator Supports, and Front Valences. Also Beds, and Tailgates.
Typically, when the Rocker Panels are rusted, they are rusting from the inside out. They are hollow, and trap moisture. The rust then begins. The rust may start on the outside, and rot through, thus spreading to the inside quickly. Rust is the equivalent to Cancer. If you leave a spot the size of a dime even, in no time at all it will begin spreading again.
Since the rocker has an Inner Rocker welded to it, the Inner Rocker is typically rusted as well. The Rocker is welded to the Cab Corner on one end, so now is the time to replace them if they are rusty. The other end of the rocker gets bolted to the back of the Fender. The Cab Floor Support is welded to the rocker panel, so it too is usually rusty. The Cab Floor Support Channel sits on the rubber Body Mount, and it's welded to the Cab Floor Support, and the Floor Pan. The Cab Floor Support is hollow as well, and it usually rots from the inside out. Now you can see that all these parts are connected. Repairing one, involves all the others. You don't want to weld a shiny new rocker onto a rusted Inner Rocker, nor do you want to weld a new Inner Rocker to a rusty Cab Floor Support. This is why most of these parts are replaced at the same time.
Just because a part looks solid, doesn't mean it is. Take a screwdriver handle, or hammer handle, and tap on the body. If it goes right through, obviously the part needs to be replaced. Don't be afraid of making it worse, if it's that bad, that it crumbles when you tap it, it needs to be replaced. You can hope it stays OK, or gets better, but when it's through a piece of metal, replacement is the only option. You can't wish rust away, or cover it up, it will just keep spreading. Many of the products on the market don't stop rust as they claim, and some do. One such product that has worked well for me in the past, is Corro-Less. It's sold by The Eastwood Company. They offer many unique tools and supplies to make restorations much easier.
Putting these replacement panels on, is a tedious task. They have to be aligned correctly, or the body lines won't match up properly. Once they are welded in place, that's it. You must check fit up many, many times, before welding each of the panels into place.
Putting them on is a process. You need something to work off of that is aligned properly. If the bottom edge of your door is rotted away, you can't work off it. If the area behind the front wheel is rotted completely away, you can work off it either. If your Cab Corner is rotted away, you can't work off it. The more of these that are in tact, as far as the edges go, the better guide you have to align new parts. Furthermore, there are factory clearances between panels. Doors and Fenders can be adjusted a bit, but the Rocker Panels, and Cab Corners must be perfectly aligned before they get welded on.
This is why when I restored my 77 K/20, I had a parts replacement order I followed. I'm not sure if it's the GM way, but it made sense to me. I was replacing a lot of parts, in fact, all that I described above. Since I knew my doors were aligned properly, but rusty, I left them on, and started with the rocker panels. I left enough strong steel on the edges when cutting off the old Rocker, to make welding on the new ones easier, and possible actually. I also removed the rotted out Cab Floor Supports. Some rust can be so extensive, that the floors would have to be replaced before the Rockers can be welded on. Sometimes, the Cab Corners have to be replaced prior to replacing the Rocker Panels as well. As long as the Floor Pans are solid enough, as well as the Cab Corners, the Rockers can be welded on. Since I was replacing the Rocker, and Cab Corners, I didn't weld my new rocker to the rotted out Cab Corners. I did weld the new Rockers on the three other edges. After I had the Rocker aligned, I tack welded it all around the three sides. I then cut back my front Fender behind the front wheel, and peeled back the sheet metal, to gain access to the front edge of the Rocker. I welded the front edge. I then removed and replaced the front Fender. I then cut off the old rotted out Cab Corner. I welded it to the new Rocker, and the edge of the door frame. I did not weld in between the bed and the cab, as I planned to remove the bed later, and weld the Cab Corners, while replacing the Bed.
After the Rockers, Cab Corners, and Fenders were on, I started on the Floor Supports. I could see the outline of them on the floor inside the Cab. I was installing a body lift along with repairing the rust, since I had to remove rubber body mounts to weld. Getting out the bolt under the cab on each side was a slight problem. Seemed the nuts were inside the hollow of the supports. When I tried to loosen them the nut inside turned. Since I could see the outline on the floor inside, I drilled a 1" hole, to gain access to the nuts. I then cut out a 2" x 2" square section around the hole I drilled. The nuts were square (4 point), and just a solid chunk of rust. No way they'd come out, so I used a 4 1/2" Grinder to grind off the heads of the bolts. I then drove them through with a drift, and pulled them out from inside the Cab. It wasn't a quick easy job. On the Passenger side, I found the Cab Floor Support Channel was crushing, since the rust made the steel that much thinner, and weaker. The Cab was sagging on that side, and now I found out why.
Since I didn't have a Cab Floor Support Channel laying around, and didn't order one, I tried another idea. I cut a piece of 1/8" x 2" x 3/4" square edge channel steel. I hammered it inside the old Cab Floor Support Channel. The flat plate on top of the channel, was rotted as well. I replaced it with a rectangular piece of 3/16" steel plate, and welded it in. I then drilled for the Body Mount bolt to go through. I welded on the new Cab Floor Support, and Inner Rocker Panel.
Notes:
* To replace the Rocker Panels, the Fuel Tank(s) must be removed, as well as the carpet, and seat(s).
* To replace the Cab Corners, the Bed must be unbolted from the Chassis, and moved back enough to weld on the Cab Corners,
in addition to removing the carpet, seat, and interior trim.
* To weld on the front edges of the Rocker Panels to the Cab, the front Fenders must be removed.
*Bare metal must be primed with a "Self Etching Primer" because 'regular' primer just doesn't bond well. Eastwood carries it in spray cans, and in quarts (for larger areas).
*Seams must be sealed with Seam Sealer. Failure to do so will result in premature rusting of new parts. Eastwood sells Brushable Seam Sealer, and they sell it in tubes for a standard caulk gun. When applied at the factory, it is done with a brush. Brushing gives the best appearance.
*Replacement body parts DO NOT come with Seam Sealer on them,
you must buy it and put it on yourself.
d.)
Beds
Keep in mind that beds are bolted together, so it is possible to change one bed side, or any section that unbolts. The parts of the Bed are: the Floor, the Right Bed Side, the Left Bed Side, the Front Box Panel, the Tailgate, the Right and Left Wheel Wells, and the Gas Tank Door(s), (depending on the year, and if it has Dual Tanks or not). The only thing holding the sections together is bolts. Roughly 100 of them. Believe me, I had to assemble my new bed, and I thought I'd never get all the bolts in! Man did I wish I had an air ratchet that day!
*When assembling a bed, or replacing sections of a bed
that bolt on, you must use a Seam Sealer in between the panels, or rust will
form. Seam Sealer is used in between the bed sides and floor, in between the
rear wheel wells where they bolt to the bed side and bed floor, and the front
'box' panel where it bolts to the bed sides*.
To remove a Bed, first you would unplug the Tail Light Wiring Harness at the rear of the Bed behind the bumper. Next remove the screws holding the Fuel Tank Filler Neck(s) on, and the Fuel Tank Cap. Underneath, check to see if your Rear Axle Vent Tube is attached to the underside of the Bed with a clamp. Remove it. Check to see if any wires are attached to the underside of the bed, and remove any that are. Next remove the eight Carriage Bolts holding the Bed to the Chassis (Frame). Lift off the Bed. You can lift it, and move it back a foot or two, and set it down on the Chassis. Here's a few pictures of my second
e.)
Tools & Supplies
There are many special tools and supplies used when doing body work. Many just make jobs go easier, while others are requirements. The most prevalent "gotta have it" tool is the MIG Welder. This is how replacement parts are attached to the existing body. Rivets and screws are out of the question, regardless of what the replacement part maker says. Welding them on, is the only way.
Some other tools that help, and I consider many of these "must haves" too.
For Parts & Supply Sources, check out my 
