Reproduction Pop Open Gas Cap Woes

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1971 Ranchero
I received one of these as a Christmas give a couple years ago and finally preparing to put the fuel tank to use. This kit came with a twist on cap (see attachment) that doesn't work. The rim contacts the mounting flange of the Pop Open. I remedied this by grinding the rim down, but the ID of the rim doesn't fit over the filler neck. It shows to be about 1/16" too small. It also doesn't tighten down against the neck, so it won't seal. I have a Stant that has some ears and even deeper rim....looks like I can make it work, but prefer a solution that doesn't require mods.

1. Does anyone have a part number for a twist on cap that fits under the Pop Open cap (and doesn't require mods)?
2. The 2nd attachment shows some parts that appear to be the OEM style of seal. There's a retainer plate, center plate, a spring, and screws. my Repop has a 3 tapped holes that look like they might work with the retainer plate in this picture. Do any of you know where to get just these parts? The link associated with that picture no longer shows this picture and I haven't been able to find this kit anywhere.

There's another cap shown on some of the repop kits (as well as the one showing the OEM style seal) that looks like a low profile version with the ears on the top. Wondering if any of you have used that version with success and what its PN is.
 

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Mister 4x4

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I have that same kit and it works just fine, although getting it on tightly takes a bit of effort, since there's nothing to grab except for the thumb ridges. I picked up a Stant replacement cap (with the ears, hoping to be able to use them to help tighten things down without wearing out my fingerprints) and it hits the inside of the cover, as you mentioned. I also intended to cut down the ears a little to make it work, but like most minor projects of that nature, I haven't gotten around to it yet.

I didn't have to cut down the edge of the cap that came with the kit, however. I just made sure the filler neck was absolutely centered in the panel's opening (I have a repop taillight panel, as well).

New taillight panel w/gas cap & cover installed (with the trunk lid I scored from a '72 - same color and sunburn and everything... but had lots of bondo):
gascap1.jpg

New paint, gas cap installed - I also caved and got a repop trunk lid):
rearend1.jpg

After working up the courage to drill holes in the newly painted panel, I got the honeycomb trim installed. It took a little bit of wrangling to make sure the gas filler neck lined up as it should so the cap still worked, though.
taillights1.jpg
 
Joined
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1972 Mach 1
1971 Ranchero
I have that same kit and it works just fine, although getting it on tightly takes a bit of effort, since there's nothing to grab except for the thumb ridges. I picked up a Stant replacement cap (with the ears, hoping to be able to use them to help tighten things down without wearing out my fingerprints) and it hits the inside of the cover, as you mentioned. I also intended to cut down the ears a little to make it work, but like most minor projects of that nature, I haven't gotten around to it yet.

I didn't have to cut down the edge of the cap that came with the kit, however. I just made sure the filler neck was absolutely centered in the panel's opening (I have a repop taillight panel, as well).

New taillight panel w/gas cap & cover installed (with the trunk lid I scored from a '72 - same color and sunburn and everything... but had lots of bondo):
View attachment 64686

New paint, gas cap installed - I also caved and got a repop trunk lid):
View attachment 64685

After working up the courage to drill holes in the newly painted panel, I got the honeycomb trim installed. It took a little bit of wrangling to make sure the gas filler neck lined up as it should so the cap still worked, though.
View attachment 64687

I've installed a new tail light panel and honeycomb. The filler is original. I took care to make sure everything was centered and aligned as the cap is a focal point of the rear and easy to see if off center.

I wonder if 72 neck is larger in OD? I measured the OD of the neck and ID of the cap and the cap is right at .050 smaller. I think this kit came from CJ Pony...maybe there are different variants going around?

In your config, does the rim of the cap fit between the filler neck and Pop Cap Mount Flange?
 

Mister 4x4

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I got my cap kit from Ohio Mustang Supply, and the filler was original as well, like yours. It's a Scott Drake product, P/N: D1ZZ-9030-C. Looks like the CJ Pony Parts is a different P/N (CJ Classics FM-EG012) as Ohio Mustang also offers that part. Must be a different manufacturer.

Yes, it 'barely' fits within the opening, and it barely sticks out far enough to be functional.

IMG_20220620_121415755_HDR.jpg IMG_20220620_121406447_HDR.jpg

Hope this helps.
 
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I was able to get the low profile cap to fit snugly but is very difficult to remove...almost had to get a pair of channel locks. I had ordered a Gates cap and after taking some measurements found I could grind down the tabs on the Gates cap such that it will fit under the flip cap and leave enough tab to get a reasonable grip on. The cap is Gates 31720. It is non-vented and has a check valve that allows it to "inhale". My measurements indicate you can let the levers protrude by 1/8" beyond the profile of the cap. Hope anyone with similar issue finds the info helpful.

 

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