Gas Cap Question?

[cobra_4]

I'm having trouble getting my gas cap to fit on my 72? (Build thread HERE) I have that stant number it calls for, it seems to have the right hooks, goes in, but it won't tighten up, there is about a 1/4 inch of play up and down. Its kept the rain out so far, but I'm afraid it might not at the car wash or something.

Here is what I've got.




Anyone see anything wrong or anything I'm missing?

['68OrangeSunshine]

It's not the right one. The correct gas cap only has the 2 tabs like the 2 shallower ones. The other long tabs are for a passenger car. Also your filler neck is really rusty.
I think '72 has a smaller diameter filler neck opening than '67 -'71.

[cobra_4]

Originally Posted by '68OrangeSunshine

It's not the right one. The correct gas cap only has the 2 tabs like the 2 shallower ones. The other long tabs are for a passenger car. Also your filler neck is really rusty.
I think '72 has a smaller diameter filler neck opening than '67 -'71.

Hmmm, according to what I'm looking up its right for a 72?
http://www.rockauto.com/catalog/more...579&cc=1410073

71 and back takes the shorter one but still has four tabs?

http://www.rockauto.com/catalog/more...565&cc=1029888

Maybe mine has a '71 filler neck? I've found a few other things on the truck that were odd for the year, so maybe it was an early truck? I don't know?

['68OrangeSunshine]

It's always possible after only 40-something years of human intervention that a fuel tank could be swapped. I know I changed out my '68 OEM tank for a '67 tank from a junkyard, after a hot-tanking and a silver spraycan paintjob and new lmc float/pickup, in 1997. Two reasons: 1] then-new ethanol gas was dissolving some bottom sediments that had built up over almost 30 years; and 2] I had buggered up the slots on the fill neck when I lost the key to a locking gas cap and had to get it off with brute force. No design change between '67 and '68. Only drawback was that the gas gauge has never read right since. "Full" is at 3 O'Clock, 1/2 Tank is at old ''3/4 full'' indicated. I've never ran it out of gas so I don't know where the bottom is. Probably around 1/4 to 1/3rd full. I know how it reads, so I know the status of my fuel level, but a new driver [in the extremely unlikely event I ever parted with my rig] might be misled.
Does your tank have the second evaporator line out of the filler neck, like a '72? Does the Gas Gauge read screwy?
I'll go outside [in 101* sun] and pull the Stant p/n off my gas cap.

[1972BlueC20]

I just bought stant non locking cap 10623 on eBay for $7 shipped. It fits perfectly, no leaks.

[1972BlueC20]

According to the stant website, 10623 is correct for the 1972.

[1972BlueC20]

Here are pictures of my Stant 10623

I have a 1972 C20

[cdowns]

that is a vented gas cap and 72 should b a non vented gas cap // i dont care what stant says in thier catoluge

[1972BlueC20]

I have a c20 3/4 ton. I was told I needed a vented cap because I don't have any emissions equipment.

['68OrangeSunshine]

I'm running Stant p/n 10623's on my '67 Suburban, '68 Stepside and '71 Jimmy. I went and looked at the '72 parts Blazer I have, and sure enough it had the 4 prong, Hi-Lo lugs like on yours. Also the '72 filler neck diameter was smaller. The 10623 Stant caps were too big to fit. I'll shoot a pic tomorrow.

[1972BlueC20]

My 10623 fits perfectly on my 72 c20

[jdfarmer]

I bought a new gas cap about ten years ago because the old one was loose and leaked a lot of fuel. The new one was loose and leaked a lot of fuel also. Looking at the top of the filler neck I thought it looked a little pulled out. So I tapped it with a hammer in a few places and the cap seemed to tighten up better. Little being good, so more must be better, I tapped it several more times around the neck while test fitting the cap, now it doesn't leak and is tight. Just a suggestion.
I am not an authorized fuel tank technician, proceed at own risk. Your mileage may vary. etc. etc. etc.

[kcsa75]

I had the same issue. I took the rubber gasket off and traced it on to some cork gasket material I had lying around. Cut a second gasket then put both of them on the cap.

Problem fixed.

[cobra_4]

Thanks for the info guys, I forgot, or didn't think about it, but when I first got the truck the shop I bought it from changed the tank before I got it, so who knows what I've got. I'm gonna grab the cap off my dad's '69 and see how it works out.