Fuel pressure building when truck is off

[cdc3jj]

Please bear with me as this may be tough to explain. The fuel pressure is building when the truck is turned off. This has happened twice now, both times within 24 hours of a fill up. First time was about a week ago. I drove the truck an hour to my folks house and filled up on the way. Stayed the night and when I got to the truck the next morning and the fuel filter was full to the gills and had a slow drip. Until this time, the fuel filter would barely have a trickle coming in which is odd to me but that's another topic. So, filter is packed full and there's a drip. I assumed the clamps are lose or the filter or rubber lines have failed. When I unhooked the filter I had a constant stream of gas. I assumed that was gravity since it seems the tank is higher than the filter. Replaced the filter and lines with new parts, no more gas leak and no more full fuel filter. Skip to this past weekend. Drove the truck to my folks again, stayed a couple nights, filled up yesterday on the way home. Walked out of my house this morning and I smell gas. Open the hood and the filter is full again with a drip coming off of it. I took the gas cap off and unhooked the line from the carb thinking that might allow any built up pressure to escape without empting my gas tank while I'm at work. I'm wondering if my cap could be bad and not allowing the tank to vent or if this is something that happens normally? I haven't seen this issue before. Both filters have been the cheap-o inline plastic housing type. I'm going to look for a glass bowl style on eBay. Thanks in advance for any help.

[unibody madness]

You need to have a vented gas cap, although I can only assume you are parked in th sun with a full tank, causing expanded had to try and vent to through the carb?

[cdc3jj]

First time I was parked in the sun. Second time was in shade on a rainy night. I'm going to see if I can find a new cap this evening. I suppose it could be rotted out or blocked up. Only got the truck a couple weeks ago and I'm still chasing gremlins.

[cdc3jj]

Took a look after work and it looks like the pressure blew the top off of the cheap-o plastic filter. What fuel filters are you guys using? I know glass bowls are cool but if they leak, fire is a possibility. The pump originally housed the filter on these trucks didn't it? Although no new pumps seem to offer that option. At least not from my google attempts.

[bruceandersson]

Buy the new gas cap from one of the vendors that specialize in these trucks. A lot of parts stores have or can order a gas cap that is not vented. The vendors have the right cap.

[Toyz]

Where is your filter mounted? These trucks operate at very low fuel pressure. There should not be enough pressure to damage the filter, especially from expansion. I'd be inclined to suspect a faulty pump relief valve, but that would likely cause carb flooding and extremely poor idle.

Paul

[cdc3jj]

Filter is mounted between the frame rail and pump. I'm looking hard at a pump with a built in filter as well as a new gas cap. Just haven't pulled the trigger yet.

[LM14]

Filter should have the fuel pushed thru it, not pulled. Your filter should be between the pump and carb. My guess is it's expanding and since the filter is low and weak it takes the brunt of it.

SPark

[ICEMAN6166]

its hard to find pumps with filter bowls or cans anymore.

y block guys can use fe\ft pumps in place of originals as the arm is the same