First, be VERY careful. No implied warranty of any kind on my free advice.
;) You simply must vent the area in which you are working and have a fire extinguisher near by. Have a hose nearby too if possible.
Drive the car around until you have about 5-10 gallons of gas in the tank.
Disconnect the negative battery lead that is closest to the hatch.
Before you jack up the car, check the obvious-- see if the fuel sender
gasket is allowing fuel to spill up into the recess area under the hatch
area. Lift the carpet up of the right hand side of your hatch. Expose the
union nut by removing the plastic bezel/cap with a putty knife. The cap is a
black circle of plastic under the carpet toward the right hand side of the
car facing forward and looking into the rear hatch. Once you pry the cap
off, you'll see something akin a jar lid with "grippy" sides. This is
"union nut." If you have gas pooling in this recess, this is where
vapor is coming from. You need a new gasket. If not, continue.
Jack the car up under the aluminum cross brace and then put two sturdy jack
stands at the appropriate rear jackpoints. As a rule of thumb, look at how
much room you will need to drain the tank into your five gallon gas can. The
stands should each (alone) support the weight of the car in my opinion.
Leave the jack itself jacked up under the cross brace for the moment. You may have to move it at some point as you are lowering the tank, but it is a
good "safety" jack for now.
When you have about 5-10 gallons in the tank, drain it from the hose
emerging from the tank. Use a vice grips with a torn rag or flannel shirt to
protect the hose while pinching it off while you disconnect it from the fuel
Drain it into an approved five gallon, red gas can. You may have to do this a couple of times depending on the angle of the hose and the nozzle on your can. I had a second car or another can I could drain into between drains. I pinched off the gas coming from the hose with the vice grips and flannel shirt.
Once the tank is empty, it is fairly light but not easy to work with because it is odd shaped. You'll have to check the manual and the Pirtle and Nichols
sites to determine how many bolts hold the brace on, but the sender also needs to come out on top. That requires disconnecting the electrical plug
and the vent hose. They were both stubborn on my unit.
I had to cut my old vent hose to remove the tank so that I could see the
vent hose. YMMV, but the hose needed replacing anyway, and then I got a good
look at it and how to string it back up into the innards of the car before I
put it back. I used an English measure hose that was a tighter fit than the
braided vent hose that came with the car (probably the original the way it looked).
So my short answer to your question is I think you need to remove the entire tank to get a look at the upper breather hose. If you are not sure it is
leaking, I think you should check the gasket seal on the fuel sender before jacking the car. If gas is pooling there, you've found your problem.
David A. Cmelik
81 5sp "moosgrunmetallic"
Thanks, that's a nice step-by-step write up. The sender is OK. I was trying
fix some electrical issues with it a few weeks ago, and all was (and is) dry up
there. Fuel only leaked after I filled it up, and I was able to see it leaking from the area where the hose goes through the hole in the body. So I figure that's the vent hose. I emptied the tank and removed some hoses today. Do I have to remove the supply hose that leads FROM that pump under the tank? I'd rather not since I'm assuming I'd need to replace those high pressure washers around the hose connection.
It looks like it will just drop now. I'm still not certain how to snake the
hose up when installing, but hopefully it will become clear when I can take a
As part of a tank service, I generally clean the sending unit. Along with
removing and replacing the tank screen, flushing the tank and replacing the tank
to fuel pump hose, I remove the sending unit, disassemble it and clean
everything up with a little Berryman's.
The outer tube on most units will be discolored towards the bottom. Clean it should be very silver. On the bottom of the unit there is a brass nut.
Remove this one and the lower plastic cover. There is second nut which has to be removed from the long shaft going down the center of the unit. At that point the entire unit comes apart. The sensor is a float that rides on two very thin wires. The center of the float rides on the center. If there is discoloration on the outer tube then the float is probably sticking. The center guide and the wires should be cleaned as well as the contacts on the bottom of the unit. The light circuit is a separate circuit from the gauge circuit. This is why there are three contacts on the top of the unit.
If the gauge in the car is jumping then there is a good chance the float is sticking in the tank. The jumping coming more at the bottom of the tank points to the fact more varnish build up occurs at the lower end of the gauge than the top. There is a 50% chance the tank will be half full so there is less chance of varnish accumulating on the tip have of the unit than the bottom.
If you disassemble the sending unit be careful. The wires the float rides on are very thin and delicate. I will generally clean the wires with a little B12 as well as all of the contacts. Once clean the float should ride easily up and down in the unit without sticking. Movement of the float when tilting the unit should be smooth with no catches.
I have found that most of the gauge problems go away once the sending unit is working right. The other source of problems are the contacts on the
Dan the Pod Guy
I can only get the fuel sending unit about half-way out of the gas tank.
At first it would only lift up an inch or so but some gentle turning allowed it to come about half-way. Holding it there and turning it results in what sounds like wires scratching on something and feels like something is trying to hold on to it.
What prompted my attempts at removing it? The gas gauge flutters around the 3/4 empty mark and has since I bought the car three years ago or so.
well the turning has now killed it, you have 2 choices, push it back into the tank and heat the collar nut in hot water then install it.
Pry the sender out with all your might and replace it.
There is a small cup part that's holding the sender it will come out you just need to use the force.
No harm in fiddling with it some more at this point. There's a baffle inside the tank and it may have gotten hooked on the cup on the bottom of the level sender.
If by 'killed it' you mean it won't send fuel that's not the case. It's still working.
According to the manual (20-15) the unit should come straight out without being encumbered but that is clearly not the case.
I appreciate your help, but I don't know why you want me to heat the collar nut. Can you explain this to me?
well if you read the WSM it will also tell you to heat the nut in hot water prior to installing it on the sender.
NOTE the sender is installed into the top of the tank and the sending portion is the fuel reading part of its operation.
The fuel line that's attached to the top of it is a return line from the engine fuel supply.
SO, by twisting the sender you may have destroyed the float reading portion of your sender, fuel can still return to the tank, and if your sender seal is still good it should seal the fuel from leaking out.
There is like a housing in the bottom of the tank...like to prevent sloshing, the fuel sender goes through it...pulling it out , the sender gets hung.....on my 78, the housing in the tank was broken by the PO. I as able to get it into position when I had the tank out and slide in the new sender.....I feel your pain!
use the force to extract your sender, the most damage you can do is dislodge the lower plate that the sender passes through, this part can be snapped back into position.
NOTE there is also a possibility that the tank has had a collapsing event and the sender has been crushed out of its original position.