'78 C20 fueling problem

[78BlueC20]

Hi There,

I was recently gifted a '78 Chevy C10 truck with the complete maintenance history and it has less than 100K. I'm wanting to use it here on the land and make it available for friends to use for projects. Before I am comfortable doing so I need to resolve a couple problems. Being somewhat mechanically inclined, I'm happy to try and fix it myself. If its more complicated, I'd like to understand it before I pay someone else to do it.

The first issue is that I can't put gas in the tank without it spilling out at my feet. I changed out the fuel hoses, both filler and exhaust, and still have the same problem. Actually it seems to be worse. There are two tanks--same problem on both sides. The exhaust hoses were pretty cracked up before changing. Previously the gas leaked out from the underside of the body. Now it wants to leaks down both sides of the body. I realize now the hoses weren't the issue though its good to have them changed. I was considering changing out the filler necks but after some research that doesn't seem to be the issue either (even though they aren't sealing, hence the leaking fuel). I believe if it did seal, I wouldn't be able to put any fuel in at all. The pump would just shut off. It seems the air is not able to get out of the tank when the fuel goes in. I see that newer models having this problem when the fuel tank vent valve is clogged but from what I can tell the part is not available for this year of truck.

My question is, is there something equivalent to the fuel tank vent valve for the '78 C20? Is there some other emissions apparatus I should be checking? Any other ideas?

The other issue is that the door has to be SLAMMED a couple times to close it properly so it won't rattle. From what I can tell, changing out the hinges should remedy this. There doesn't seem to be a spring so it should be pretty straight forward aside from supporting the door properly and wrestling the pins out.

Am I missing anything?

Many thanks for your input!

Cheers,
Laura

 

[78BlueC20]

Now I see it is probably the vapor canister.

Does a clogged filter cause the problem described?
Where is the canister located?
Is it easy to access?

Next step seems to be changing the canister filter.

Thanks,
Laura

 

[Zembonez]

The fueling problem was common on those trucks(especially true when getting full). The level of the fuel opening wasn't much higher than the tank . I remember my dad having the issue back when I was a kid. The canister won't have any effect on the fuel going in.

Those trucks had door hinge and latch problems over time. LMC truck should have a "fix it" kit available for it.

 

[dirtyoldman]

On my old '77 I had to forcefully hold the fuel nozzle against the body or it would fall out of the filler tube & then fall to the ground.That's the ONLY thing I missed about that truck.I never found a cure for that

As far as the door...mine wouldn't close all the way either,but,I found a temp. cure.I took a piece of fuel line hose and cut it just long enough to fit around the striker pin on the body.I then split it so it would fit around the pin,and zip tied it.That gave the latch in the door something bigger to grab onto.It would last about a year IIRC.Hope this makes sense

 

[Bernie]

On my old '77 I had to forcefully hold the fuel nozzle against the body or it would fall out of the filler tube & then fall to the ground.That's the ONLY thing I missed about that truck.I never found a cure for that

As far as the door...mine wouldn't close all the way either,but,I found a temp. cure.I took a piece of fuel line hose and cut it just long enough to fit around the striker pin on the body.I then split it so it would fit around the pin,and zip tied it.That gave the latch in the door something bigger to grab onto.It would last about a year IIRC.Hope this makes sense

New strike bolt is just a few bucks at any good auto supply.

 

[txab]

If you need to do anything with the hinges, there are hinge pin/bushing kits available at your local auto parts place. Strike bolts available as well. I own a '79 and '80 model and know what you're talking about