Fuel Leak Help

[TKCR]

Just got my 86 C10 SWB out of the garage yesterday. It has been sitting for a couple of years, in the garage in a dry controlled environment. When I started it up, it started with just a small drip on the passenger side, back where the tank is. Drove it around the neighborhood and pulled back in the driveway. It now has a steady stream of fuel, leaking. It stopped after a few minutes of the truck being off.
What I don't understand, I am driving off the driver's side tank. Are the fuel lines not separated, from tank to tank? Or should I say, side to side? Is there a way I can get the passenger side to completely shut off from the fuel? I need to take it and get it fixed, but the fuel is dripping to close to the exhaust, for my liking.

[Goats86]

The selector valve is on the passenger side. Probably just a short piece of rubber hose rotted between the steel line and valve. Typically you have the sender unit at tank, a short rubber hose, then to the valve all on the passenger side. You will actually have 2 hoses there. Fuel feed and vent. On the driver side, you have the sender unit, short rubber hose, steel line, then short rubber hose to valve. Could be any or all rubber hoses around the valve since they are 30+ years old.

[pofo]

That just happened to me. It was the hose from the drivers side tank that where completely rotten and started to leak near a hose clamp under the passenger side, near the switch valve. I had to loosen the bed and drag it back an inch or so to get to the hose from the tank.

[TKCR]

The next day (yesterday), i crawled under there with the camera phone. I was actually able to use the camera feature to look around, and I was able to better what all was up there. I obviously have some rusty lines, but it is most likely the rubber hoses that are dry rotted. I will have to get it hauled somewhere to get these fixed.
I did take a few pics.

[Rich84]

I had a similar leak.. I ended up having to get a new sending unit. The return line on the 30 year old sender had rotted out. The rubber was not leaking.

[Dead Parrot]

Just fixed something similar on my 75. Cause was a mouse that decided 42 year old rubber tasted good. Ate holes in the main lines from both tanks. And sampled one sender wire. Did the slide the bed thing since both 20 gallon tanks were full. At least the bed and bolts were in good shape.

[RUN GMC]

Had that some time ago.....it was the selector unit and it was leaking out the plug in for the wiring.....replaced it with the hi pressure rated one the only place that had it locally was the hub Autozone........

[Jeepwm69]

Originally Posted by Dead Parrot

Just fixed something similar on my 75. Cause was a mouse that decided 42 year old rubber tasted good. Ate holes in the main lines from both tanks. And sampled one sender wire. Did the slide the bed thing since both 20 gallon tanks were full. At least the bed and bolts were in good shape.

To slide the bed back, do you just have to put an impact on the bed bolts, take them out, and then slide it back? Tail light wires etc can stay in place?

[pofo]

Originally Posted by Jeepwm69

To slide the bed back, do you just have to put an impact on the bed bolts, take them out, and then slide it back? Tail light wires etc can stay in place?

That is correct. I also loosened the rear bumper, removed one bolt on each side and turned it downwards a little, to make room for the bed. The tail lights wires was long enough, so no trouble there.

[Dead Parrot]

Spray bed bolts with your favorite penetrating oil several times during the couple of days preceding your repair. Helper or something to set on the bolt heads once loose, otherwise they keep wanting to rise out of the square hole and spin.

8 bed bolts, gas tank fillers, tilt the bumper down, drop spare tire. No need to play with tail light wires.

Crow bar and several short 2x wood blocks to help convince the bed to move once the bolts are out. Only needs to go back a few inches.

[Jeepwm69]

Thanks! I tried to do it a couple of years ago with a ratchet and quickly gave up. I have an impact now so it's on my to-do list

[TKCR]

Update:
Got the truck back yesterday, it was the Selector Valve. They put in a new one and replaced all the rubber hoses.

[Palf70Step]

Glad to hear she is back going (safely) again.

[44th Miss Inf]

Now drive that thing. Too good looking of a truck to just sit in the garage!

Glad it was an easy fix.

[TKCR]

Thanks!! I did drive it, as soon as I picked it up, we drove 1 1/2 hrs to the guys place that will be painting the hood. I also had the shop replace the radiator, it was starting to seep. She ran great, except for the rough idle at the stop lights. So maybe just a little adjustment.
It's also the first time on the highway since having the vent windows rebuilt. It was a lot quieter!! She will definitely be driven more, once the hood is painted. I won't have the excuse of no time in another 6 months, I will be retired at that time.