Acknowledgement: I would not have attempted and could not have completed this part of the restoration without the patience and help of Brian McLaughlin a.k.a. "redwingvette" to corvetteforum members. I hope this article helps others.
1980 Rocker Channel Replacement
Michael R. Kearney
I must ask you one question before we begin. Do you really want to do this on your own? While it is reasonably straight forward it involves some very hard work. If you don't have the time, patience or tools I suggest you take it to a Corvette restoration shop. Ok, let's get started. We've established your either not very smart or your the adventurous type.
How did you determine you need to replace the rocker channels? The best way is to pull the kick panels in the interior off in the front (see figure below left ) and the plate in the wheel wells in the rear (see figure C below) and inspect with a flashlight and screw driver. Caution: Don't poke your finger in there unless you want to risk rust poisoning. Your looking at body mounts #2 & #3 (figure A & B). If it's really bad you'll see plenty of rust and metal flakes easily visible. Check to see how high the rust has migrated up the pillars of the "birdcage". You'll need to weld the new rocker channels to these pillars.
At this point let's discuss a few special tools you'll need to complete this project:
Note: I highly recommend Harborfreight when purchasing tools. Their extremely cheap and offer a wide assortment of good tools for the casual mechanic.
Since this isn't an article on how to do a body lift I'll just point you to the article I used. It's a piece by Kevin Mackay written while removing a body.( Body Removal ) You'll need to build a stand to place the body on after you've lifted it off the car. Make it sturdy and high enough to give yourself plenty of room to work. (see figure below).
Assuming you have the body off and setting on a stand let's discuss what you must do to remove the old rocker channels. I've taken a drawing from my 1980 Corvette Assembly Manual and drawn the 3 areas that must be removed. Sections 1,2 & 3 are spot welded to the pillar areas and floorpan of the birdcage.
Below is a picture of the front section of my passengerside rocker channel. As you can see it was badly rusted. I assume the body was touching the frame. The other body mount positions were rusted out even worse.
Let's examine where the spot welds that connect the rocker channel to the floor pans are actually at. Again I've copied some illustrations from the assembly manual. In (figure 2) below you will see where the rocker channel is spot welded to the floorpan compartment. These spot welds can be grinded down from inside the rocker channel and are therefore easily accessible (see figure 4 below, this is a cut away drawing of the driver side rocker channel). I found this to be the most tedious part of the project. You may need to put a wire brush on your air cutter and clean the area up in order to see the spot welds. I used cutting wheels in this area as much as possible although grinding is preferable. You need to be careful not to cut into the floorpan however.
In the next illustration below (figure 3) we can see where the spot welds are at on the pillar areas and the inserts in the front of the rocker channel. To get to the inserts you must first remove the channel. The spot welds between the inserts and the channel are typical already rusted and should be relatively easy to separate.
The image below is a set of badly rusted rocker channels that were removed by persons unknown to this author.
The images below illustrate what your car should look like from underneath after removing the rocker channels and inserts.
You need to clean up the inside of the pillars and spray primer to prevent future rust. Below is a photo of a new rocker channel ready to be installed. I purchased my rocker channels (item# 19150) from Vette Products of Michigan (248) 693-1907 or website for $125 dollars each. Some other online sites offer this replacements.
I aligned my rocker channels to the center of the two holes in the sill plate area (see figure below). Use bolts and nuts to hold the rocker channel in place while welding. The new rocker channels fit up nicely into the front and rear pillars allowing you to attach the assembly and weld from inside the port in the rear fender well and inside the pillar behind the kick panel in front. One note, I did need to use some shims between the pillar and new rocker channel area when welding the assembly into place. Set your welder to a low voltage when welding the rocker channel to the flloorpan or you'll cut right through the thin surface of the floorpan.
If everything goes smoothly your new rocker channels should look like the images below. You need to decide if you'll use rubber or the newer polyurethane body mounts. I dropped the body back onto my frame in about 45 minutes with the help of a few friends.