Installation of An Electronically Controlled Hidden Gas Door

The "new-model-year-blues" has hit more than a few of us when we've come to realize that our car wasn't the latest and greatest any more. It's a dilemma that has been going on ever since the beginning of automotive time (and, of course, helps sell new cars). While the '55 Chevrolet was ahead of its time in many ways when new, after a few years had passed it was in the history books.

Over the years, many things old have seemingly become new again and we are still updating and thinking of "new" things for our favorite Tri-fives. Rocky, at Rocky Hinge, has developed something new for the '55 to help it catch up to--and surpass--its Tri-Five brethren in terms of its (to some) ugly flap-style gas door, which is located dead square in the middle of the left quarter panel. He made it possible to relocate the gas filler behind the taillight, like the '56 and '57s, but made the taillight open electronically with the flip of a switch from inside the car.

To see just how meticulous a system the Rocky's kit is, we took a short trip to Firehouse Fabrication where owner/fabricator Brett Maxwell had our project '55 Bel Air anxiously awaiting the subtle yet significant change.

Here is the '55 two-door post project car at Firehouse Fabrication. It's been the host of many updates and it's not stopping there, sounds like a perfect candidate for the power hidden gas door.
Here is the '55 two-door post project car at Firehouse Fabrication. It's been the host of
This is the kit, complete with the wiring harness, motor plate with motor, filler neck and mounting plate, and new taillight socket and bulb.
This is the kit, complete with the wiring harness, motor plate with motor, filler neck and

After removing the taillight assembly, the horizontal mount gets cut out.
There is a seam on the inside of the quarter-panel that needs to be ground down for clearance of the motor plate.
There is a seam on the inside of the quarter-panel that needs to be ground down for cleara

Bolt "part A" to the motor plate. Our kit came with stainless hardware-- make sure to use anti-seize on the threads.
Bolt "part A" to the motor plate. Our kit came with stainless hardware-- make sure to use
Trim the lip in the taillight opening so that "part A" will replace it once it gets welded in. When fitting and trimming, make sure that from the outside, bottom of the taillight opening to the back of the motor plate(towards the front of the car) measures close to 8 1/8 inches.
Trim the lip in the taillight opening so that "part A" will replace it once it gets welded

With the filler neck plate attached to the motor plate we can see that it fit pretty well inside the quarter-panel. With both sheet metal pieces fitting well and measuring correctly "part A" gets tack welded in.
With the filler neck plate attached to the motor plate we can see that it fit pretty well
We had to figure out a way to anchor the top of the filler neck plate to the inside of the quarter-panel. Brett quickly drilled a hole in a little piece of angle iron then we put everything back in and marked a spot on the filler neck plate to drill the matching hole. Disassemble, drill 1/4-inch hole for the 1/4-inch 20-bolt, bolt angle iron to panel, install, and then weld the angle iron to the top of the inside of the quarter-panel.
We had to figure out a way to anchor the top of the filler neck plate to the inside of the

The stock taillight socket has to be removed or it will interfere with the gas filler. We cut the end off with a cut-off wheel and CAREFULLY ground the rest off with the angle grinder with a 60-grit disk.
The stock taillight socket has to be removed or it will interfere with the gas filler. We
We used the template in the kit to mark the hole for the new taillight socket. Center punch your mark, drill an 1/8-inch pilot hole, and finally we used a hole saw for the socket hole.
We used the template in the kit to mark the hole for the new taillight socket. Center punc

Bingo! In goes the new bulb and socket. There is a plug in the kit to plug the old hole.
Brett came up with a simple way to mark the blind holes in the motor plate to mount the tail light housing. First, cut the heads off two 1/4-inch 20 X 3/4-inch bolts. Next, grind and dress the cut end. Screw them into the motor plate and leave maybe a 1/4 inch out.
Brett came up with a simple way to mark the blind holes in the motor plate to mount the ta

Brett had this piece of 5/8 inch tube in the scrap pile and quickly cleaned it up. Now, place one end over the cut off bolt in the motor plate. Grab some spray paint and give a couple of squirts inside the tube.
Brett had this piece of 5/8 inch tube in the scrap pile and quickly cleaned it up. Now, pl
Doing this will leave ample paint on top of the cut off bolts, but won't get everywhere else. Quickly put the taillight housing in its place in the quarter-panel and plant it firmly on the motor plate while trying not to move it around too much and smear the paint. When done right, it will leave two little paint spots on the bottom of the taillight housing.
Doing this will leave ample paint on top of the cut off bolts, but won't get everywhere el

After center punching our marks, we drilled 1/8-inch pilots and then 5/16-inch holes. Start with that to give you a little adjustment. Check that out! It worked perfectly!
After center punching our marks, we drilled 1/8-inch pilots and then 5/16-inch holes. Star
We bolted the housing in place and just so we didn't get ahead of ourselves, we hooked up some temporary power to the motor and did a test run. Not bad for the first run, but we needed to do some trimming.
We bolted the housing in place and just so we didn't get ahead of ourselves, we hooked up

Since the taillight isn't permanently attached to the quarter-panel any more we can trim these tabs flush with the rest of the opening. Other than that there were just a few spots around the opening that the housing was rubbing on.
Since the taillight isn't permanently attached to the quarter-panel any more we can trim t

Next, we slid the new filler neck in from the taillight side of the mounting panel so we could leave the cap on it and install the taillight to check for clearance from the back of the taillight to the filler cap. Make sure the filler is on a downward slope toward the gas tank. With that looking good, mark the flange position on the filler neck and take it all apart. Slide the flange on the filler neck to your mark and make sure there is room enough to thread in the 90-degree fitting for the vent tube. Now, we can tack the flange to the filler neck.
Next, we slid the new filler neck in from the taillight side of the mounting panel so we c
This is what the filler neck looks like after everything checked out, it was welded and got a coat of paint put on it. Notice the hole for the vent tube fitting.
This is what the filler neck looks like after everything checked out, it was welded and go
We had to come up with a way to connect the new filler neck to the old filler pipe going to the gas tank, so after some thought we decided to try using a 2-inch mandrel J-bend from a local muffler shop to redirect the old pipe.
We had to come up with a way to connect the new filler neck to the old filler pipe going t

After some good "eyeballin'" we figured that the old pipe was going to have to be cut a little below the mounting bracket. With the remainder of the old pipe being held back in position in the car, and the new filler neck bolted in place, hold the J-bend on the outside of the quarter-panel at the same angle as the new filler neck and mark in the bend area of the J-bend where it would meet up with the old pipe. Try to make the cut through the J-bend as square with the side of the tube so that after its cut, the opening isn't oblong. It needs to fit well to the old pipe because they are going to be welded together.
After some good "eyeballin'" we figured that the old pipe was going to have to be cut a li
We did all the cutting "long" so that we had room to trim more off if needed. We installed everything again to check the fit. I know this will sound far-fetched because nothing ever happens this easy, but everything fit perfect! It's almost like we planned it that way. With a few hands holding everything together, mark across the seam in the tubes to verify their position to each other, and then remove the tubes. We lined up our mark with the tubes on the bench and tacked them together. We reinstalled it and everything still looked great.
We did all the cutting "long" so that we had room to trim more off if needed. We installed
The new tube assembly was close to the original mounting bracket inside the quarter-panel which made it easy to utilize it again. We cut the bracket off the discarded filler neck piece and ground off the old brazing. With a little tweaking, the bracket fit the contour of the J-bend. We put the bolt through it and held the filler tube in place and tacked the bracket to it.
The new tube assembly was close to the original mounting bracket inside the quarter-panel

This is how it looked through the stock gas door opening. Pretty slick, huh?
Since everything fit and looked good, ace editor Grant Peterson was itchin' to get his hands dirty. So, he tried out Brett's new TIG welder and welded up the filler assembly.
Since everything fit and looked good, ace editor Grant Peterson was itchin' to get his han
The one thing we did have to trim (now that everything fit) was the end of the new filler pipe that was butted up to the new filler neck. 2 inches got cut off. We had to do this so there was room for the new 2-inch diameter gas hose to be installed. Make sure you use gas hose because it's designed to withstand the chemicals in gasoline and won't break down over time.
The one thing we did have to trim (now that everything fit) was the end of the new filler

With the lenses and bezel back on you would never know what lurks behind, just how it's supposed to be. Check the swing of the assembly again with everything together. We found a few spots that needed just a little more trimming.
With the lenses and bezel back on you would never know what lurks behind, just how it's su
You can also adjust the height with the washers that are supplied, side-to-side would have to be adjusted by slotting the mounting holes in the tail light housing. The only fabrication left is to weld up the stock gas door.
You can also adjust the height with the washers that are supplied, side-to-side would have
From the new wiring harness, this is all that plugs into the motor.

This is the toggle switch for the motor. It can be mounted in the dash, under the dash, or wherever you want it.
This is the toggle switch for the motor. It can be mounted in the dash, under the dash, or
This is the relay panel that comes with the leads to the motor and toggle switch wired up. All you do is connect a power and a ground. The panel is meant to mount under the dash. This '55 has an aftermarket A/C unit installed and space under the dash is limited. It would be easy to mount it out of the way in the trunk. You would just have to make longer wires to the toggle switch and shorten the wires to the plug.
This is the relay panel that comes with the leads to the motor and toggle switch wired up.