Looking for some help with this: The smell of gas in the cab of my 1951 Chevy 1/2 ton forced me to replace the filler neck, hoses and clamps as well as the gasket at the sender. Also replace the filler cap (these parts were new parts). I did get rid of the smell of gas but when I unscrew the cap to put in gas, the pressure nearly sends the cap flying. At first I thought it was vacuum but its not---pressure is building in the tank and can't seem to escape. Any thoughts on this? I have visions of my tank exploding. I noticed on the new cap, there appears to be a 'blue plastic' item in the center. Would this item have anything to do with the pressure release (maybe not working). Thanks.
I would double check but I think you need a 'vented' cap. I sounds like you have a non vented one. Steve;-)
I think you are correct Steve. He may have a cap that has a pressure release valve. Some of those will vent around 1 psi. Doesn't sound like much until you see and hear it. If I remember correctly, the original cap was vented, and did not use a valve. Good luck....Mike
You have the wrong cap , it can be dangerous so get rid of it NOW ! . The correct fittment cap is the same for ALL GM gasoline trucks from 1937 ~ 1970 so hurry down to Pep Boys , Shuck's etc. and look in the STANT catalog , get a nice shiny new one . I'm using a locking typ filler cap but it leaks a bit when the tank is full and I turn left . -Nate
Thanks for the suggestions and recommendations. The cap was included in a 'fuel filler neck kit' that I ordered from LMC part number 32-3347. The cap looks very much like Chevy Duty's 23-107. I will try to find a replacement locally.
RE: Gas Tank Pressure - Problem Fix Well, I bought a Stant Gas Cap, part number 11623 - cost was $4.10 with tax at the local Advance. I put it on the truck and four hours later, took it off with NO Pressure relief whatsoever. Some further checking, the Stant cap looks very close to the one that Chevy Duty has (with the sticker and red letters warning of pressure when opening) - the cap from LMC does not have this sticker. I probably should have bought the cap from Chevy Duty and may not have experienced this problem. The Stant cap has a metal relief valve and the one from LMC was plastic. It could be that the Stant has a lower pressure relief - the gasoline smell may come back near the cap. Thats ok with me - much better than the massive shock of that relief of pressure when opening the cap. Thanks again for the suggestions. Hope I can repay someday. Roger Myrtle Beach, SC
