Fuel tank removal

[Racin_jason]

I've got an 81 c10 and I'm trying to plan out removing the fuel tank before I start. It's just a single tank on the drivers side. Any links or words wisdom you kind folks care to share with me.
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[willem445]

Are you removing the bed at all? It would be much harder with the bed off. You need to disconnect the wire and fuel lines at the tank obviously. Then there are 4 bolts on each brace/strap that connect to the frame. You can get to these easily from underneath. I used some buckets and placed them underneath the tank to hold it up while I removed the bolts. Might take some maneuvering to get it to drop down, especially with the bed still on. Its pretty straight forward to remove the tanks in my experience.

What are you removing the tank for? Cleaning? Replacement?

[Racin_jason]

Originally Posted by willem445

Are you removing the bed at all? It would be much harder with the bed off. You need to disconnect the wire and fuel lines at the tank obviously. Then there are 4 bolts on each brace/strap that connect to the frame. You can get to these easily from underneath. I used some buckets and placed them underneath the tank to hold it up while I removed the bolts. Might take some maneuvering to get it to drop down, especially with the bed still on. Its pretty straight forward to remove the tanks in my experience.

What are you removing the tank for? Cleaning? Replacement?

No I'm leaving the bed on. I'm not exactly equipped to remove the bed at this point. I was planning on dropping the tank. It's mechanical fuel pump, but the rubber hose on the top of the tank has a small, small hole, I also have to figure out why the fuel gauge isn't reading right now.
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[Alex V.]

The bed is just 8 carriage bolts and a few odds-and-ends like tail light wiring, differential breather tube, etc., and two good stout guys can lift it off carefully. Depending on what shape your tank straps, etc. are in you might spend less time lifting the bed off than trying to drop the tank out from under it. Once the bed is off you can easily access everything you're wanting to address. It's really not as daunting as it sounds.

But in regards to your original question, it should be the fuel filler neck, plastic tank guard pan bolts, then the strap nuts and the stuff up top. I did it to both tanks on an '86 K20 3 months ago, and honestly, it wouldn't been a bear to do if I'd not removed the bed first. It took me 2 1/2 hours to get the bed off, and that's with rusty hardware. Best of luck.
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[willem445]

Originally Posted by Alex V.

The bed is just 8 carriage bolts and a few odds-and-ends like tail light wiring, differential breather tube, etc., and two good stout guys can lift it off carefully. Depending on what shape your tank straps, etc. are in you might spend less time lifting the bed off than trying to drop the tank out from under it. Once the bed is off you can easily access everything you're wanting to address. It's really not as daunting as it sounds.

But in regards to your original question, it should be the fuel filler neck, plastic tank guard pan bolts, then the strap nuts and the stuff up top. I did it to both tanks on an '86 K20 3 months ago, and honestly, it wouldn't been a bear to do if I'd not removed the bed first. It took me 2 1/2 hours to get the bed off, and that's with rusty hardware. Best of luck.
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It depends alot on the state of the bed. Mine was rusted on really bad (was replacing it anyways) and it was a pain to remove. Ended up just torching off all the bolts and buying new hardware for the different bed. But it is way easier to access everything. You might not even have to remove the tank if you are just diagnosing issues with the hoses etc if you would remove the bed.

[willem445]

Also, if you do remove the tank I would go ahead and clean the inside of the tank and inspect for rust or other contamination. I cleaned mine with vinegar and seemed to take care of the rust really well.

[tucsonjwt]

My method:

First, wear safety goggles (not glasses), a dust mask, and clothes you don't care about wearing again. You will get filthy dirty. Allow 2 hours for complete tank removal.

1) Open the fuel filler door and remove the 3 screws that attach the filler neck to the body.

2) Get under the truck and remove the hex bolt that secures the ground strap on the underside of the fuel filler neck flange to the body.

3) Remove the hex bolt that secures the ground wire from the sending unit to the frame rail. Most likely, this bolt is on top of the frame rail, so you may have to run your hand over the top of the frame rail to feel for this bolt. It will be close to the back of the cab.

4) Move some concrete blocks and 2 x 4s under the gas tank to support it until the wood is snug under the tank.

5) There are 8 cap bolts holding the two gas tank brackets to the frame rail. Spray PB blaster or other penetrant on these bolts. Remove these 8 bolts. Be careful with the last bolt so the weight of the tank does not strip the threads. If the bolts don't come out easily, spray more PB blaster and come back later. Expect rusty bolts. If you snap off the head of a bolt you will have a lot more work to do in order to get the broken piece out of the bracket.

6) Remove 2x4s and one block gradually from the rear of the tank. When the tank is partially lowered you can reach up to the front of the tank and disconnect the wiring from the sending unit and also remove the clamps from the fuel lines. You will need some lighting to get a good view of this area. Once the fuel lines are disconnected you can remove all of the 2 x 4s and blocks and the tank will be on the ground, along with the attached front and rear bracket.

7) Don't remove the brackets unless you have to. I would chase the threads on the bracket mounting holes and also chase the threads on the mounting bolts. I use a cheap tap and die set from Harbor Freight.

8) If your brackets are rusted to a dangerous condition, you can get used brackets on Ebay. You will have to clean, sand, and paint them, but they will still be better and cheaper than aftermarket.

9) If you still have a plastic rock shield attached to the bottom of the tank, it will come off with the tank and need not be removed. The plastic shield is held in place by a threaded stud that is press fit into the mounting bracket from the top side. The nut that attaches to the stud and the threads of the stud will be damaged, so you need to exercise extreme care if you remove it.

[LuckyLightning]

I found this video to be pretty helpful. I'll be moving my tank soon as well.

[tucsonjwt]

If you have a full length plastic skid shield you will have to remove the bolts hanging it to the additional side brackets prior to tank removal.

In my opinion, using an impact wrench is risky on rusty old bolts. In a warm climate the bolts may be in good shape, but in the rust belt you are likely to snap the heads off rusty bolts. I would not risk it for 10 minutes of additional effort.

[Dead Parrot]

Try to time your tank dropping with being almost out of gas. Not having 120lbs of gas in the tank does make the job easier.

Start spraying all the bolts and screws with penetrating oil a few days before the project. It sometimes takes a while to undo 35+ years of rust.

Locate a source for the fill hoses, sending unit, tank brackets and straps in case you discover they need replacing or you do something that results in one or more needing replacing. Knowing where the parts are before you start can speed getting it back on the road.

Now would be a good time to replace that 35 year old ground wire and frame terminal.