I recently bought an '88 F150 351 that has dual tanks. The guy I bought it from pointed out that the rear tank always shows full but told me that he had not put fuel in the rear tank since he owned the truck. If that tank really is full, I don't trust whatever is in there.

Today I'm going to put a hose in the tank and see if there's anything in there. Either way, I have read the posts on the "tank filling the other tank" issue and have decided that I would rather remove the rear tank since I'll never use it.

Is it fairly easy to remove that rear tank? It looks like I could drop it right out the bottom. Also, can I remove the DFR since I'll only be using one tank? Do you just hook the 2 lines from the engine up to the tank and call it a day?

Thanks!

 

Well it would be better to go to a salvage yard and get a single tank reservoir and plug it in where you take out the DFR or you may have surging problems.

 

x2...

OR... you might have a bad fuel sending unit that always reads full. that's what mine did until I replaced it last summer... I'm working 100% now.

Did the 87-91 trucks have the tank filling the other tank problem too? For some reason I always thought it was the 92+ trucks that had this problem...???? Guess I'd like a little edification myself...

 

To answer your question... IF the tank is full, it'll be a PITA to remove from the bottom side and you'll likely tilt it and get a mouth full of old gas. It's easy enough to release the hardware and drop... My truck is always full of dirt back there and it always falls off in my eyes and face... I had more electrical work and exhaust work to do so I cut the bolts loose and removed my bed to make it easy on myself... but hey that's just my opinion...

 

I have only heard of the 92+ filling the rear tank when on the front (exception below)
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The 89 and older would fill the front tank when they had a sticking "O" ring in the DFR for the return fuel. This was the most reported problem with the DFR.

But have only heard of one or two posts of the DFR filing the rear tank when on the front but not sure if the poster knew what they were talking about..

 

That's kinda what I thought... In that case I would suggest replacing the sending unit and syphining old gas out. Then he can run both tanks... JMO though.

 

If my year isn't one that has the tank issue, then I might just clean it out and leave it on there. I'm going to put a flatbed on the truck sometime soon so IF I remove the tank I'll wait until then. I have other things to do to it before then, I just wanted to get a heads-up on this. I was hoping my bad gas mileage was due to the tank issue but I guess it's just the nature of the beast!

Thanks for the input guys, at least now I don't have to be paranoid about the overflow issue. I'm here to learn and every little bit helps me out.