GM Truck Club Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
232 Posts
Discussion Starter · #1 ·
In the prociess of removing the rusty rear brake line, I jostled the rusty fuel line enough to put a crack in it...I now have a fine mist of fuel that sprays all over my back axle...it would make a perfect torch if it somehow sparked off!!

So it is time to remove the fuel tank so I can replace the hard line. I wanted to check here for tips before I start. Besides removing the fuel from the tank first..any suggestions about dos and don'ts? Judging from the weight of my 20 gal fuel tank of my 71 pontiac..I assume this thing is a beast..can one person remove it safely from under the truck?

My sub is an 89 3/4 ton and has the skid plate around the tank..I seems there are 3 bolts holding the skid plate up?
 

·
Premium Member
Joined
·
1,625 Posts
Not sure how many bolts on the 89 but I think, and don’t hold me to this cause my memory sucks. But I think my 94 had 4 bolts.

If you can get as much fuel out as possible you can save a lot of grief.

After removing the skid plate you have the tank support straps themselves. PB Blaster is the best rust breaker I have ever used, spray the crap out of the 2 back bolts a day before you intend on removing the tank. Then again before you try to loosen them, at least. But before removing them you need to release the rubber hose from the tank inlet at the filler neck. Stuff a good size rag in there to keep crap from falling in there. Then remove the ground wire from the fuel pump that is attached to frame rail. You can drop the tank without doing this but it is a lot easier and you won’t have to worry about braking it.

A floor jack and a peace of plywood is what I use to lower the tank. The ply keeps from damaging the tank with the jack, and give you a more stable support.


Now remove the support strap bolts with an impact gun if you have one available, it just makes it so much quicker, an air ratchet will work sometimes. Lower the tank with the floor jack slowly, last time I took mine out the tank itself was stuck up in between the frame rails so I had to wiggle it a little to get it out. Oh ya it was also stuck to the floor pan and I had to pry it away from it before that.

Once it’s down you will need a special tool to remove the fuel lines from the tank, they are cheap at most local parts stores under 10 bucks.

Then drag the tank out from under the truck and remove the pump sending unit combo. I used a brass punch and a hammer to remove the lock ring, you should use a non sparking tool for that just to be safe, but I have used a regular screwdriver in a pinch and I’m still here.

Just reverse the process to reinstall.
 

·
Registered
Joined
·
232 Posts
Discussion Starter · #3 ·
Thanks 84! It is good to know that the tank is sometimes wedged between the frame rails, knowing this will prevent me from searching for a missed fastner!

Since all I need to do is replace a fuel line I don't think I"ll need to remove the sending unit will I?

I've also read about cutting an "access door" (a.k.a. a hole) in the floor of the back of my burb just above the sending unit. Would this allow me to access the place where the fuel line connects to the sending unit and diconnect it? I only bought this truck for $500, so an access door isn't going to hurt the value of the truck!
 

·
Premium Member
Joined
·
1,625 Posts
No you shouldn’t have to remove the pump/sending unit. I got carried away. Oops.

As far as the hole in the bed sure if you make the hole big enough and in the right place.

Just make sure you don’t use a die grinder or spark making cutting tool, if you have gas everywhere already we could be reading about you in the paper.

An air chisel/hammer with a panel cutting tip, looks like three fingers makes a nice cut and doesn’t spark.
 

·
Registered
Joined
·
2 Posts
Fuel pump question

No you shouldn’t have to remove the pump/sending unit. I got carried away. Oops.

As far as the hole in the bed sure if you make the hole big enough and in the right place.

Just make sure you don’t use a die grinder or spark making cutting tool, if you have gas everywhere already we could be reading about you in the paper.

An air chisel/hammer with a panel cutting tip, looks like three fingers makes a nice cut and doesn’t spark.

I am trying to do mine also. I have a few questions before I proceed. Do I disconnect the fill and vent hose before, during, or after the tank is dropped ? Is there anything else holding the tank up besides the 2 staps ? It still seems pretty solid. or do I just pry it down because it is stuck. Thanks for any help.

The New Guy
 

·
Registered
Joined
·
1,667 Posts
Big aside, and something you guys already know, but sometimes in the rush to get it done, it can get missed.

Spend a lot of time and a lot of degreaser cleaning everything under there with a hose or a pressure washer if you have one. It is so much easier to work on a old vehicle that is just slightly grungy as opposed to a fully grungy vehicle. The gunk is usually so thick that some sort of stiff brush is helpful. An hour of cleaning is usually worth it.

Good luck,
Charlie
PS My Suburban is old-98 2wd 1/2 ton- with 208,000 miles, so I carefully read all the "how tos" and follow everyones steps thru repairs/replacements. When you two guys get a chance maybe you can let us know how it went andany other "tricks' you picked up along the way.
 

·
Registered
Joined
·
232 Posts
Discussion Starter · #7 ·
T1743

Only the two straps are holding the tank up. but beware...the fuel lines AND the wires running to the sending unit will be connected. Lower the tank slowly and watch for when you can disconnect these things. The fuel lines on mine were so rusted and brittle that I just broke them off. The electrical connectors were easy enough to still remove when I could reach my hand up there.

The filler hose will provide a pretty solid hold on the tank becuase it hooks up over the frame rail, so you kind of have to lower the tank at an angle and then slide it over to get the filler hose out from the over the frame.

But the only things officially holding the tank to the truck are the two straps, just that the rest of the stuff can create snags etc.
 
1 - 7 of 7 Posts
Top