Fuel level sensor gasket

[davekp]

Filled tank up the other day. Have a leak from somewhere on the top of the tank. Siphoned about 4 gallons and drip stopped. I suspect the fuel level sensor gasket? Lowering the tank for examination will have to wait until my lift is clear of another "project".
What is the part number for the sensor gasket? Where to get it?
Spent an hour searching online to no avail.
Thanks in advance!

[65 Cobra Dude]

Mark Reynolds at Breeze Automotive should have them.

Henry

[rich grsc]

Try google : mustang fuel pump gasket

[FFinisher]

Factory Five supplies an "O" ring with the kit. The parts come packaged with a square shaped O ring. (that sounds wrong) FFR supplies a round shaped o ring that should be used.

[Papa]

https://www.amazon.com/Motorcraft-CG805-Fuel-Pump-Tank/dp/B004A2D1HS

[rich grsc]

Factory Five supplies an "O" ring with the kit. The parts come packaged with a square shaped O ring. (that sounds wrong) FFR supplies a round shaped o ring that should be used.
The square shape is the correct one to use. Coat it with engine oil when installing it.

[FFinisher]

The square shape is the correct one to use. Coat it with engine oil when installing it.

I use the round one. They don't leak,which is why FFR has supplied them, I have used these on .... probably 20 builds for the sender and the pickup or pump hanger.

[davekp]

OK, opinions are mixed.
Is the same seal used on both the level sensor and fuel pump?

[edwardb]

OK, opinions are mixed.
Is the same seal used on both the level sensor and fuel pump?

Yes. You'll get mixed opinions on round vs. square. I've used both and haven't had an issue. Properly installed I think either will work. Using some lube is important. Or some recommend a very light coat of gasket sealer. Like Permatex or whatever. But probably you'll get different opinions about that too. One other thing though. Check to make sure it's not the filler tube seal that's leaking. My experience is that a failure there is more common than the two you've mentioned. Also can be affected by how much gas is in the tank.

[frankb]

I have a new one (2-1/4" dia. approx square cross-section o-ring) that I will mail to you if you wish. PM me

[rich grsc]

Ford in the past always used the square cross section gasket, I see now that they use the round shape, so yes, either is fine to use. If you think you will need to remove the sender or fuel pump in the future, then a lube such as oil is highly recommended, I think Permatex would be difficult to get apart, and then cleaned up?

[cnutting]

I had square ones and they leaked. Tony Z sent me some o-rings and that fixed it. Also replaced the fill tube seal with a Ford part as edwardb suggested since the kit supplied one developed a leak.

[Jeff Kleiner]

OK, opinions are mixed.
Is the same seal used on both the level sensor and fuel pump?

Dave,
They are both the same. As I recall when I built your car I used the square profile rings on both...but that's been 6 or 7 years ago and I can't even remember what I did last Tuesday so I could be wrong! As others have said though either will work.

Jeff

[AdamIsAdam]

Reviving an old thread...

I just got my new-to-me MKIV this week (wahoo!). Today was my first drive. I filled it up with gas until the pump auto-stopped. I drove 2 miles and parked in the driveway and gas was dripping out on the far right rear corner. it was NOT coming from the drain hose from the filler neck area. The tank is dusty and so I can see that the filler neck hole on the side of the tank appears NOT to be leaking. So I assume gas is leaking from one of the gaskets on either the sending unit or the pickup. When the car arrived to me it had about 1/2 a tank and was not leaking and was odor free. I drove it 30 miles and it is not actively dripping any more, but the garage (and HOUSE!) smells badly of gas.

Short of dropping the tank, how can I tell if it's the pickup or the sending unit that's leaking?

Is is possible I have gas trapped inside the plastic tub/liner and that's why it smells? I got my hand with a towel all the way to the top of the tank at the pickup and it seems dry. I wiped as much of the top of the tank as I could from beneath lying on the ground.

I figure I'll try and drive it a lot tomorrow to bring the tank level down, despite the 40* temps. At least the seat heaters work.;)

I have a manual fuel pump on the engine.

How hard it is to drop the tank? I'm not sure my hydraulic quickjacks will fit under the car. I have to see where to jack the car up from. Suggestions welcome!

[i.e.427]

Reviving an old thread...

I just got my new-to-me MKIV this week (wahoo!). Today was my first drive. I filled it up with gas until the pump auto-stopped. I drove 2 miles and parked in the driveway and gas was dripping out on the far right rear corner. it was NOT coming from the drain hose from the filler neck area. The tank is dusty and so I can see that the filler neck hole on the side of the tank appears NOT to be leaking. So I assume gas is leaking from one of the gaskets on either the sending unit or the pickup. When the car arrived to me it had about 1/2 a tank and was not leaking and was odor free. I drove it 30 miles and it is not actively dripping any more, but the garage (and HOUSE!) smells badly of gas.

Short of dropping the tank, how can I tell if it's the pickup or the sending unit that's leaking?

Is is possible I have gas trapped inside the plastic tub/liner and that's why it smells? I got my hand with a towel all the way to the top of the tank at the pickup and it seems dry. I wiped as much of the top of the tank as I could from beneath lying on the ground.

I figure I'll try and drive it a lot tomorrow to bring the tank level down, despite the 40* temps. At least the seat heaters work.;)

I have a manual fuel pump on the engine.

How hard it is to drop the tank? I'm not sure my hydraulic quickjacks will fit under the car. I have to see where to jack the car up from. Suggestions welcome!

Here you go, don't even need to drop the tank.
https://www.autozone.com/fuel-delivery/fuel-filler-neck-seal/dorman-fuel-filler-neck-seal-577-501/380823_0_0?spps.s=5635&cmpid=LIA:US:EN:AD:NL:1000000:IEN:7170000006084941 4&gclid=CjwKCAiA1fnxBRBBEiwAVUouUsxKhQR1_oRJz5V8o93J c-k71RKMQ3SLHlYD3imjm7tIPq3rqe120xoCvl4QAvD_BwE&gclsrc=aw.ds

[AdamIsAdam]

I guess it's safe to say my sending unit gasket is leaking. I couldn't go to sleep without knowing, so I put the car up on my QuickJacks (that was easier than expected) and looked around. Looking at the tank design, do you all agree that there's no way the leak can be coming from any other place than the sending unit gasket since it's in the middle of a valley, right? And the dust on the tank was only wet from the center out (meaning, gas didn't spill out of the pickup gasket and flow up and over the ridge and into the valley where the sending unit resides).

122199
https://youtu.be/ybGdqmVyDV4


PFA:

122200

[rich grsc]

Looks like the locking ring isn't fully tight

[Nigel Allen]

check if fuel is weeping past the seal on the fuel gauge sender. Mine leaked after a few years when tank was reasonably full. leaked fuel got trapped in the plastic tank protector and stunk the place up. Replaced it with an O ring of larger cross sectional area. I also run a charcoal canister, but also have purge set up to my Coyote. I find my canister causes some pressurisation of the fuel tank. I suspect this may have assisted the fuel to get past the seal.

Overall it works as intended with no smell.

HTH, Cheers Nigel in South Oz

[AdamIsAdam]

Looks like the locking ring isn't fully tight

Really? That would be relatively easy to fix! Here's another pic. Are you sure?
I found this good close up vid:
https://youtu.be/2C5u_t8u2pU?t=316

122212


check if fuel is weeping past the seal on the fuel gauge sender. Mine leaked after a few years when tank was reasonably full. leaked fuel got trapped in the plastic tank protector and stunk the place up. Replaced it with an O ring of larger cross sectional area. I also run a charcoal canister, but also have purge set up to my Coyote. I find my canister causes some pressurisation of the fuel tank. I suspect this may have assisted the fuel to get past the seal.

Overall it works as intended with no smell.

HTH, Cheers Nigel in South Oz

Nigel,
I was worried about that issue (of gas being caught between the tank and the plastic cover). Did you have to drop the tank to clean that or did it eventually just dry/evaporate?

Can you tell I'm trying to avoid dropping my tank? lol

The car has 1300 miles on it, but is 6 years old. I just drove it 60+ miles this morning and 85 since filling up in hopes of getting the level down low enough to stop leaking and stinking up my house!

How big are these tanks? 15? When I filled up I had about 1/4 tank and I believe I took 14 gallons.

[jrcuz]

I believe the tank capacity is 14.6 gals.
JR

[AdamIsAdam]

Lock ring is in place correctly (see pic). I guess the gasket is bad. With 85 miles driven, it no longer smells up the garage and obviously, the top of the tank is dry. Good to know until I have time to address this. I'm not sure I can get the gasket in while working on my back without dropping the tank.

122242

[frankeeski]

I believe the tank capacity is 14.6 gals.
JR

It is actually 15.4 gallons.