85 gas leak

[cfix502]

i have a 1985 k10 with dual tanks i bypassed the box and im running just the driverside tank but after driving it for a while it leaks the rest of my gas out what could be the cause and how can i fix it

 

[Swims350]

well first off where is it leaking from?

 

[Irishman999]

Two things I have noticed that cause a fuel leak, both have happened to my 85K1500.

The hoses that are connected to the servo for switching between tanks go bad. I had one go bad very recently and I think Hotrodpc had the same problem with his.

The other thing that happens is rocks, gravel and sand getting between the tank and plastic shroud on the bottom of the tank, either a rock rubs a hole in the tank or it just gets small rust holes.

 

[crazy4offroad]

My dad's transfer valve went bad in the "in-between" setting, meaning it wasn't set for the left or the right tank, but rather both. So he can fill up both tanks and it will draw off both of them. If you're not seeing an actual leak it could be back-feeding or syphoning, or equalizing over into the other tank. Pop says that happens on his truck. I gave him a new valve but he hasn't put it on yet lol.

 

[cfix502]

i by passed the box completely but still dont no where it was leaking from dont make any since before i just took the fuel line off the tank straight to the fuel pump but left the return and the everything else hooked to the box t

 

[HotRodPC]

Did you bypass all 3 hoses? I have a feeling your gas is sneeking back to the valve thru one of the smaller lines and its leaking about of the valve of the hoses on the other tank. I do beleive, and not 100% on the purposes, but I do believe you have the main fuel line. Then you have an evap line and a vent line. I just fixed a similar probably on my 85 K10 and it happen to be one of the smaller lines that was leaking all my fuel out. Not the main bigger line that goes to the fuel pump. How the line even got pressure, I'm not certain, but trust me, it was leaking badly. I think I was getting 3 gallons to the mile before I finally lifted the bed and replaced the hose that was dry rotted and had a complete break in it. Good Luck with it. Do come back and let us know what fixed your issue.

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