I am planning on dropping my gas tank to change the fuel sending unit to fix my gas gauge. I already grounded the wire from behind the tank to check if the gauge was working and it did go straight to E which tells me it should be this sending unit.

I was just going to replace it with this one form AAP.

Dropping the tank seems simple enough, I just wanted to double check with you guys on something first. Will I need to disconnect the two lines that feed into the tank first or can I just drop the tank first and then take that off?

Thanks

Picture of the lines
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Picture of bolt
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I'd cut the lines first.

You're going to replace them anyway, and you don't want another thing to mess with while the tank is hanging in the air.

Sometimes you get lucky and can clean the contacts and re-use the senders.

- Eric

 

Cut both lines? Where is the best place to get the right size lines... just any hardware store?

Thanks

 

Sure. You'll probably need to cut them to get them off the steel lines anyway.
Just remember there may be gas in them thar lines, and try not to take a shower.

Auto parts store. It's fuel line (not vacuum line or radiator hose, or smog line).

You're welcome.

 

I guess I'll make the snip this week around here and just start replacing.

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I'm browsing the advance auto parts site and they have a lot of nylon fuel lines. I can measure after I take it out, but does anyone know if its the 5/16 or 3/8 wide? Actually, I think I just answered my question in that the new sending unit is a 3/8 output. Do I also need union connections?

 

You just need some hose and maybe hose clamps if those are shot.
Best to just bring in pieces of the old hose to be sure it's the right size, but if you clean up the old ones, you'll see that they have the size marked on them, too.

You can go with some kind of fancy nylon lines if you want, I guess (I really don't know much about them), but all you really need is regular rubber fuel hose.

- Eric

 

I'm wondering why you have to cut the lines at all. Can't you just loosen the hose clamps and pull the lines off the ends of the metal tubes? That's what I did when I dropped the tank on my '67 Delta 88. Those hose clamps have hex-head screws on them, don't they? You can get a 1/4-inch or whatever size it is socket on them and turn them pretty easily.

In your photo, the line on the right looks like it hasn't been on there very long as it's not very dirty. That clamp ought to loosen right up.

Yes, the lines are of standard size. Take the old ones with you to the store and get new ones of the same diameter and maybe a foot longer than the ones that are on there. Then cut the lines to the exact length needed when you get them home. In my case, I installed the line (there is only one on my car), without cutting it to size, on the tank before raising the tank back into position. Then I routed the line properly to the other metal line coming from the front of the car that it attaches to, held it up against that line, and then marked it and cut it.

 

For the two bucks or whatever for new line, I'd just cut it and avoid wrestling with it in a tight place over my head, lying on my back. But that's just me.

- Eric

 

Actually, as I think about what I did, I don't have a memory of struggling to reach up under there to loosen a clamp. Now that I think about it, what I dd was to loosen the line at the other end, where it connects to the steel line coming from the front of the car. That's right out in the open and easy to get at.

Also, once detached, I was careful to direct that tube downward into a bucket to catch any fuel that might still be in it. Where the line connects to the line coming from the front of the car is at the highest point because it is routed over the axle. If you disconnect there, there is no pressure on the fuel to force it out of the line and onto you. If you take a pair of cutters and just snip the line at the other end, there is the possibility that fuel could spray or drip on you. I then took the tank off the car with the hose still attached and then loosened the clamp and removed the hose.

When installing, I just reversed this. Put the hose on while the tank is off the car, raise the tank into position, and then route and cut the hose and connect it to the other line.

 

A few other things to think about when dropping the tank:

1/ First, make sure you really need to drop it. As I understand it, you grounded the wire from the send unit to the gauge and saw the gauge go to E. But did you check the wire that grounds the send unit to the body? it's at the front of the tank. It snaps on to the send unit (wiggle that connection) and screws to the floorpan.

2/ Drain the tank! I prefer the suck-on-a-hose-and-get-a-mouthful-of-gasoline method.

3/ Disconnect the clamp and/or bracket which holds the filler neck to the body (behind the rear bumper). On a lot of cars this bracket is missing, but if it's there, you need to remove it.

4/ Disconnect both wires.

5/ Disconnect the fuel hoses you've been talking about.

6/ Disconnect the vent hoses on the front of the tank. They attach to a little plastic surge tank which is held to the floorpan with a backet. You can disconnect the surge tank (if it's there) or the hoses.

7/ Use penetrating oil on the two bolts holding the front of the tank straps. If they're covered with undercoating, you're screwed.

 

Definitely, but keep in mind that it is impossible to get all the gas out. It's very difficult to get a hose to lay flat on the bottom of the tank or to dangle just above the bottom. I just kept the siphon going until I couldn't get any more out.

When you think you've gotten as much of the gas out as you can, go ahead and drop the tank. Don't be surprised if there are still three or four gallons in there no matter how much you've tried to siphon it out. The tank will still be light enough, though, that you can handle it pretty easily. What I did was just tip the rest of gas out through the filler neck into a large bucket. At the end of the job, I put that gas back into the tank with a large funnel.

Needless to say, I did all of this outdoors.

 

I don't need to worry about there being much gas in it. I ran out of gas last time I was driving it and had less then my 2 gallon reserve in the trunk.