So apparently my truck is an anomaly, I have a 1991 F150 standard cab long bed, 4.9 E4OD 4x4 with dual tanks.

EVERY thing I’ve found said I should have a 19 Gallon midship tank but it is in fact a 17 Gallon tank. It needed a fuel pump so I bought a 19 Gallon pump and got it to fit in there and it seemed to work fine. However now I found a hole in that same 17 gallon tank and need a new one. So I have some questions:

- Can I put a 19 Gallon tank in my truck since I already have the pump for it?
- Are there any adverse effects from having a 19 gallon pump in a 17 gallon tank?
- If I can’t put a 19 gallon tank in my truck would it be ok to continue to use the 19 gallon pump? (I can’t return the pump missed the return window by 2 days!) I’d rather not have to buy a new pump if I can help it haha

The truck is from the rust belt so I’m just gonna replace the tank. Let me know any advice or anything because I’m kinda at a loss and want to make this truck right and even better, it was my grandpas truck.

thanks!
Jake

 

RockAuto sells a 16 gallon and a 19 gallon midship tank for your truck. Nothing mentioned about fitment issues, so I would go with the 19 gallon tank since you already have the correct pump.
Your truck looks good for a rust belt truck.

 

haha yea I’ve been doing my best to get the rust off the frame and coat it lately probably knocked over 10ths of rust off of it here’s some pics of it before haha




I had to replace the cross member because it was rusted through even

 

I was wondering about the new nuts and bolts. You have done a great job on the rust. Nice work.
In a message dated 6/25/2022 8:09:46 PM Central Standard Time, noreply@ford-trucks.com writes:

 

Thanks for the compliment! Used an angle grinder and drill with brush attachments and an air needle scaler. On areas that will be hard to get to in the future, they will get Rustoleum Rust-Reformer and Cosmoline RP-342 (best rust protectant I could find after a lot of reproach) and the rest of the frame inside and outside will get the RP-342 also.

I did a BUNCH of research trying to find info and I just put them in a few days ago but they should hold up but here's what they are and some tips:

- All hardware is Grade 8, I got it all from Tractor Supply as they charge you buy the the pound ($4.59 per lbs I think) which is WAY cheaper.
-They only had zinc coated so thats what I got
- 10 Bolts: 1/2-13 x (I believe) 2 1/2in long
- 20 Washers (to sandwich the frame with)
- 10 lock washers
- 10 Lock Nuts
- Red Permatex Threadlocker Gel (easier to apply and cheap on amazon)
- Order of assembly: Bolt head->washer->frame->washer->lock washer->thread locker->lock nut
- Torqued them down with my 1/2inch Milwaukee Impact till the lock washer was flat and compressed (about 100-120 ft.lbs. probably). (I made the mistake with the first one of letting my impact really get after it and broke the bolt haha)
I think in all I spent about $7 for all the hardware and like $10 for the thread locker.

To get the 1/2in bolts to fit you need to drill out the frame and cross member, and I cannot emphasize this next part enough, GET THE RIGHT DRILL BIT! I made the mistake of using a big 1/2in Dewalt drill bit and I almost broke my thumb (really bad sprain) when that stupid thing kicked back on me and it almost got my wrist too. Go to harbor freight and buy this $6 step drill bit (https://www.harborfreight.com/1-4-qu...ill-44460.html ) IT MADE IT SOOO MUCH EASIER!!! And it never caught, I just put the drill on 9 (I was dumb and was using it on the hammer setting) and it was like butter! once I pounded the crossmember into the frame I had to drill out the holes to match the frame, so keep that in mind too.

As a whole it wasn't too bad! and is WAY better than the old one that was rusted through and almost broke with me trying to get it out. To get through the frame rivets I used 2 different methods, first one was an angle grinder with a cutting wheel to but a cross in it, then a grinding wheel, then drilled them out and used a hammer and punch to punch them out and a chisel and hammer between the crossmember and frame to pop it loose. The second was way easier, I just used an air chisel and air punch. Then you need a Big hammer and just knock it out (driver side backward and passenger toward the cab) and the reverse that to put the new one in.

That was a lot to be said but it was pretty straight forward.

Old nasty crossmember

crossmember out, and then I coated the inside of the frame with Rustoleum Rust-reformer.

Old (has a crack on the right side) vs new- I got it out of a truck in a u-pull it yard, cleaned it up and hit it with rust reformer and will finish it in Cosmoline RP-342

new one in place

top bolts, there are 2 bottom bolts too

Inside shot of the frame rail, heads and nuts are 3/4 I believe and just put a wrench on the nut and hit it with the impact.

 

If the frame allows it (it should since you got the long bed but check spacing between crossmembers anyway) get the bigger fuel tank since you already got the pump for it.

A tip for your future frame repairs - split-lock washers have no business on a frame. You'll never find them where Ford put in factory bolts and nuts - always flanged all-metal locknuts. Now those nuts are pretty expensive to buy and usually not readily available at your hardware store anyway, so using Grade-8 washers and nylock nuts has proven to be an acceptable alternative. Which you got those, so good job there. But those split lock washers were not needed, and just add a future failure point (they like to spread when tightened a lot, especially when an impact wrench is involved).

Another tip - up to and including 1/2" size, you're best off undersizing the washers (at least the washers typically sold by the pound of weight even if they're grade 8). Like using 7/16" washer on a 1/2" bolt, 3/8" washer on 7/16" bolts, 5/16" washer on 3/8" bolts, and 1/4" washers on 5/16" bolts. Hell I think I used 1/2" washers on the 9/16" shackle bolts even. I forgot what the reasoning for washers almost always running a size larger when you actually measure them was, but I find it hella dumb when you're working on anything more high-tech than a cow pasture fence.

 

Thanks for the great advice! I hope I don’t need to use it anytime soon but I’ll do that next time, I heard mixed things about the lock washers so I just went for it, hopefully it lasts a long time!

I sure hope it’ll fit my only concern is that perhaps the combo of 4.9, E4OD, and 4x4 makes the drivetrain too long and the 19 gallon tank would be too close to the transfer case. I just can’t find anything else about why mine would have the 17 gallon tank. If anyone has my same combo and a 19 gallon I’d love to hear about it or see pics!

 

As you said, all info says your LWB should have come with a 19 gallon midship tank. I think it may have been replaced with a short bed tank which I believe was 17 gallons.. If mine, I would go 19 gallon.

 

An odd thing is that I went to salvage yards and looked at other LWB trucks like mine, expect none had the E4OD, and they all had the 19 gallon tank. However a big differentiator with my truck is that it had the E4OD and I have an additional cross member that the front of the 17 gallon tank mounts too. The 19G mounts the the cross member that’s under the back of the cab I think I have a picture to show it. Now that additional cross member on my truck is actually bolted on and can be unbolted. However oddly enough all of the other trucks with 19G tank not only does not have the crossmember but they don’t even have the holes for that crossmember. Any thoughts?

This is from a bullnose but the frames look identical otherwise with the other bricknoses but they all had beds on.

 

Have you checked the door jamb sticker to see if the transmission code is E? Also, what is the DOB of the truck? How did you determine the existing tank is 17G?
Is the existing tank plastic or metal?
EDIT: Looking on LMC and RockAuto show a 19GA tank length as 58.875". The 16GA tank is 42.375". No vendor shows any difference between tanks and transmissions. So I don't believe your E4OD or 4X4 makes a difference in tank size. Neither is offering a 17GA tank. Check the above lengths and see if one matches what you have.

I just looked at my 91 F250 LWB and the rear tank measures 58.875= 19GA. My cross members look identical to yours with the 3 bolts on the rear like yours. My E4OD tail shaft doesn't come close to the tank. I am 2WD.

Another thing I just noticed is your midship filler hose is way forward of the larger 3 bolt cross member. Notice the blue truck filler is much closer to the larger cross member like mine is. Unless you have moved the location of the filler hose more forward when working on the truck.
If you moved the filler hose for the picture then yours would look the same. My front tank strap is right where yours is and my tank goes under the cab a short way. I think if you use a straight edge down the inside of the tank and going forward to the cab measure the 19 GA tank distance. If your transfer case is not in the way, 19GA should be fine IMO.

 

1996 lwb normal cab e4od. i realize not what you have but the crossmember is there obv and this is from the pass side, viewing to the driver. so you can see filter and the tank where it "cuts off" and you can prob infer the cab position better than I can from this but would be normal stock

 

Thanks y’all these do help a bit. In response yes I’m positive I have the E4OD and it’s 16GA (some places say 17 or 16.5GA too so idk haha) it only measures around 42in. I guess I’ll try the 19GA out and if it doesn’t work then I can always return it, but I sure hope it works.

I don’t have a picture but in the owners manual for the truck when it lists wheel base and tank size under my configuration there is a “5” in the upper corner denoting a special condition but it doesn’t list what “5” means anywhere there so beats me. If anyone knows that’d be great!

Hopefully it all fits right, I’d sure like the extra capacity of possible! If anyone else has any other input I’m all ears haha

 

Well guys I remeasured everything and the 19 gallon gas tank will be literally touching the transfer case and the rear shock at 59 inches, so unless anyone has a picture it looks like I'll have to bit the bullet and get a new 16 gallon tank and pump unfortunately.

 

That is so strange. It's almost like you have a short bed.

 

Yea it’s strange that’s for sure and very unfortunate. But yea I have 133in wheelbase standard can with 8ft bed but apparently my specific drivetrain is a bit longer than the rest 🤷🏻‍♂️