In the last update I had found areas of corrosion and deterioration around the base of the windshield frame / birdcage that extended beneath the firewall area. This means that both the front clip and firewall needed to be removed to allow a proper repair of the steel frame.
In this update I’ll focus on removing the front clip from the Corvette body. Keep in mind that at this point the body of my Corvette has been removed from the chassis so the only attachment points I’ll be dealing with are the areas where the front clip is bonded to the firewall. These bonding areas are located at the front and back of the firewall on the driver and passenger side and also along the front top edge of the wiper compartment. To begin the removal I started by separating the front clip from the top of the wiper compartment. The photo below shows some of the excess bonding compound that oozed out of the joint at the factory when the two pieces were bonded.
To develop a good working point to start with I used a sharp utility knife to score the bonding compound near the center of the firewall. This bonding compound is pretty rugged stuff. I’d compare it to Bondo texture wise, but it’s a much tougher and more rugged material.
After scoring the joint I used a combination of putty knives, screwdrivers, wedges and a 5-in-1 painters tool to separate the pieces. A 5-in-1 painters tool is basically a putty knife with a variety of different angles (see photo below). These angles came in handy when working in some of the tighter areas.
It probably goes without saying that a lot of care needs to be used during the entire front clip removal. Considering the toughness of the bonding compound, and relative brittleness of the fiberglass, it’s real easy to cut into or through the +/- 1/8″ thick fiberglass that the front clip is made from. So, with a hammer and the painters tool I carefully worked at separating the hood surround and firewall by starting in the center and working out toward the sides.
This first part went pretty smoothly and it only took about a half hour to get the two pieces separated.
Next I worked on separating the front clip from the firewall. As mentioned earlier, the clip bonds to the firewall in two locations on each side of the car – in the front of the firewall along the engine compartment, and at the back of the firewall near the door jambs. The rear firewall bonding area on the passenger side was next on my list. The tricky part here was finding a starting point. The location of the bonding surface was not readily visible due to some of the finishing techniques they used during assembly at the factory. I found the best way to get started was to carefully drive a screwdriver or wedge between the bottom of the fender and the steel rocker channel. This caused a crack to form at the bonding surface between the firewall and fender. I then used the 5-in-1 tool and hammer, starting at the crack, to continue separating the firewall and fender.
Here’s where the 5-in-1 too came in really handy. The cove section of the tool allowed the tool to stay centered (front to back) on the bonding strip as I worked my way up the fender. As mentioned earlier, the exact location of the bonding surface is hard to see above the tool. It appears that the factory used the excess bonding compound that oozed out of the joint during assembly to form a smooth surface between the edge of the firewall flange and fender.
Once I reached the top of the firewall I moved toward the top of the fender and worked at separating the fender from the firewall in that area. This was a real tricky spot since the firewall in this location is pretty thin and flimsy. I was successful at separating the pieces on the passenger side of the car, but I ended up damaging the diver’s side. For whatever reason the firewall fiberglass in this area seemed extra brittle and rather than the bonding compound giving way, the fiberglass did. This isn’t a huge deal, but it just means more work down the line to properly repair the firewall.
Now that the front clip has been separated from the rear section of the firewall I moved onto separating the front clip from the front portion of the firewall. The photo below, taken from the underside of the passenger side fender, shows the locations where the front of the firewall is bonded to the fender and hood surround. The red arrow is showing the bonding strip that forms the joint between the hood surround and front clip while the green arrows show the flanged areas of the firewall that are bonded to the fender. Although it’s tough to see in the photo below, the flanged area of the firewall actually ‘steps in’ to provide clearance for the front fender/hood surround bonding strip. In other words, this bonding strip runs continuously from the front of the car, past the front firewall bonding area, and then terminates at the rear firewall bonding area. This ‘stepped’ surface of the firewall flange made separating the two pieces without damaging the front clip pretty tough…
In fact it made separating the pieces so tough I did end up damaging my front clip – on both the driver and passenger side! The two photos below show some of the damage that occurred at the bonding strip location. The dashed red line in the photos below approximate the location of the bonding strip while the red arrows point out areas of damage that occurred during removal. Unfortunately, the joint between the hood surround and front fender is a weak area and the bonding compound does it’s job very well. Even though I was being extra careful on the second fender I still ended up damaging it a bit at the area of the bonding strip. Luckily the damage is not very severe and should be relatively easy to repair.
In fact it made separating the pieces so tough I did end up damaging my front clip – on both the driver and passenger side! The two photos below show some of the damage that occurred at the bonding strip location. The dashed red line in the photos below approximate the location of the bonding strip while the red arrows point out areas of damage that occurred during removal. Unfortunately, the joint between the hood surround and front fender is a weak area and the bonding compound does it’s job very well. Even though I was being extra careful on the second fender I still ended up damaging it a bit at the area of the bonding strip. Luckily the damage is not very severe and should be relatively easy to repair.
There really wasn’t any special trick to removing the front clip. Mostly we needed to be sure that we didn’t get the clip hung up on anything as we lifted it out of place. Obviously care needs to be used to avoid damaging the clip during this process. The front clip is quite flimsy once it’s removed from the firewall so this is definitely a two person job. Fortunately it doesn’t weight that much (perhaps 50 pounds) so lifting it up and out of place was no big deal.
And finally, here we have the clip removed from the rest of the body…
the firewall and birdcage with the clip removed…
and a few pictures of the bonding areas on the firewall. Now that the front clip has been removed the bonding locations are readily apparent. For anyone planning to complete this same task I suggest taking a few minutes to study these photos. Hopefully they’ll remove some of the guess work from the process.
In the next update I’ll focus on removing the firewall from the birdcage. As mentioned earlier, this will allow me to properly repair the areas of deterioration that were found around the windshield frame. Stay tuned!
