I've been reading alot of posts on this valve and wanted to know if I should check anything in the tank when changing it. The rear tank never has worked. When I switch to the reaar, it sputters and dies out. The gas has been in there so long it stinks like varnish. It seems to be the pumping gas into that tank issue. It also explains the 5-6 mpg. My plan was to drain the tank by siphon, get the replacement valve for $219 and swap that out.

At this point, I'm just assuming that is it. Can I test the valve with a clean 5 gal tank and hose? I thought the pump was in the tank? How can I check that pump? I'd prefer to drop the rear tank and valve. I thought about a LMC 38 gal tank, does that need the bed off?

I don't know how gummed up that tank is. I'd like to drop it and start fresh from the valve back, but its an extra truck I use occasionally for hauling and don't need to drop $600 into it.

 

What engine? Only some of the 460's had electric pumps in the tanks.

What type of fuel lines does it have running around under the truck? The plastic ones?

 

Its the 460 and from the sound they make when the key turns on, it appears to have electric pumps.

 

from here, i would suspect the pump in that tank has failed, or will fail soon due to the old gummy fuel in there. i would suggest pulling the tank, opening it up, and deciding if its worth cleaning out or just replacing.

if your goal is to stay low-budget and you don't really need the second tank, it wouldn't be hard to simply bypass the TSV and only have the single tank.

if you decide to get the current rear tank back into use, i would suggest putting a cheap clear filter in its line before the TSV so any gunk you didn't clean out stops there instead of in your main filter.

and yes, you can test it by running a hose down to your gas-can on the ground.

 

All that can be done from underneath? It looked like id have to drop the tank to get the pump out regardless.

 

if you need to get that pump out of the tank, i would do it by lowering the tank just enough to get the sending unit out. this can be done with a floor jack and a block of wood under the tank, with the wood being used to spread the force and avoid damage. support it with the jack and remove the mounting straps, then lower the tank a bit. i've had them apart without disconnecting the fuel filler hose, which is sometimes hard to remove and harder to reconnect properly.

this job it a little easier if you're using a tranny jack instead of a floor jack, but not enough to be worth investing in one.

obviously, when you have the tank open, you'll want to look inside with a flashlight to see just how gunked-up it really is.

 

I owned a 1986 F-350 with the same issue and did almost exactly what he said. My tank actually had algae (green gas) in it. I did end up pulling the whole tank out and flushing it. Siphoning gas out of the tank regardless of how nasty it tastes makes life a lot easier when it comes to removing the tank.

 

your word choice suggests you're using your mouth in the process. this method includes a significant risk to yourself, and there are better/safer ways, which i'll list a couple of
1) use your mity-vac to suck on the hose, being careful to get enough air bubbles out so you have a full enough hose of fuel to work with.
2) set your siphon hose in place dry, with both ends at their required point, then point an air nozzle into the tank filler, with a rag loosely in place to help seal and prevent splashing out. the pressure will quickly start the siphon in your hose
3) place a cheap electric fuel pump in the middle of your siphon hose and let it do the work

there are a variety of other ways as well, i just listed the first few i thought of.

 

I've used a pump when I had one available but didn't always have one available. The above reference was an attempt at humor. There is a risk to doing this but there are also tons of other risks when dealing with fuel tanks and gas that we need to be aware of. I'm sure the OP knows this as well and will take the information shared here and use it in a safe manner.

 

Make sure you dont use a lighter to see inside your tank. Ive heard of people doing that before.