My gas tank only leaks when it's 90% full

[avdeveloper]

I went for a full tank of gas today and started to smell fuel inside the cabin. I checked underneath and found that the gas tank was leaking fuel. I also noticed that the pump didn't make the usual click that tells me it's full.

After taking out gas to about less than 90% (ballpark), the tank stopped leaking. What could have caused this? My guess is pressure in the fuel system? I read somewhere that the excess pressure is released at the charcoal canister but if that's clogged then pressure would build up? Maybe I misread.

Here's a thread from the 100 series: Post in thread '2006 LC w/ LRA Aux 24 - Fill, Venting, Fumes, Dripping & Over-Pressurization Issues'

LRA Aux 24 Fuel Tank - How to Modify for 100s from 2006-2007.

(UPDATE 03.09.23 - THE LRA AUX 24 CAN BE MADE TO WORK FOR 04-07 100 SERIES, BY MAKING MODIFICATIONS TO THE SHIPPED FILLER NECK & TANK, ADDING TWO ELECTRIC BALL VAVLES TO ISOLATE THE LRA FROM THE FACTORY TANK/EVAP SYSTEM, AND FINALLY ADDING A MARINE-STYLE SNORKEL VENT FOR THE SYSTEM. SKIP TO...

forum.ih8mud.com

Could a fuel system cleaner help remove the clog, if that is even the problem?

Here's a video:

 

[gummycarbs]

leaking gas from top of tank

i took a look at these two threads IH8MUD™ Forums - Search Results but feel free to point out any others youve seen. I filled up last night to the tune of $100 bux and come out this morning and the cruiser smells strong of gas inside. I wrote it off as coming from the tool bags i just pulled...

forum.ih8mud.com

There's a compound curve stamped into the tank, which can crack. Might be it

 

[Godwin]

Might be a loose hose clamp. I dealt with this last year thinking the tank was leaking but it was only a loose hose clamp.

 

[BILT4ME]

I went for a full tank of gas today and started to smell fuel inside the cabin. I checked underneath and found that the gas tank was leaking fuel. I also noticed that the pump didn't make the usual click that tells me it's full.

After taking out gas to about less than 90% (ballpark), the tank stopped leaking. What could have caused this? My guess is pressure in the fuel system? I read somewhere that the excess pressure is released at the charcoal canister but if that's clogged then pressure would build up? Maybe I misread.

Here's a thread from the 100 series: Post in thread '2006 LC w/ LRA Aux 24 - Fill, Venting, Fumes, Dripping & Over-Pressurization Issues'

LRA Aux 24 Fuel Tank - How to Modify for 100s from 2006-2007.

(UPDATE 03.09.23 - THE LRA AUX 24 CAN BE MADE TO WORK FOR 04-07 100 SERIES, BY MAKING MODIFICATIONS TO THE SHIPPED FILLER NECK & TANK, ADDING TWO ELECTRIC BALL VAVLES TO ISOLATE THE LRA FROM THE FACTORY TANK/EVAP SYSTEM, AND FINALLY ADDING A MARINE-STYLE SNORKEL VENT FOR THE SYSTEM. SKIP TO...

forum.ih8mud.com

Could a fuel system cleaner help remove the clog, if that is even the problem?

Here's a video:

You spent a lot of the searching other places for leaking fuel tanks.

Search this forum for a fuel tank leak and you'll find that these tank have a tendency to crack in one place.

The only other possibility is that your fuel hoses are leaking.

Remove your 2nd row seats (8 bolts) and remove the fuel pump cover from the cabin and look at the hoses to see if you can spot the leak.

This is literally 30 minutes to check, an hour if you're slow.

If it's a cracked tank, buy a good clean used tank and swap.or buy a new tank. Yes they are available.

 

[avdeveloper]

Might be a loose hose clamp. I dealt with this last year thinking the tank was leaking but it was only a loose hose clamp.

ok I'll go ahead and remove the fuel tank protector and see where the leak is really coming from.

leaking gas from top of tank

i took a look at these two threads IH8MUD™ Forums - Search Results but feel free to point out any others youve seen. I filled up last night to the tune of $100 bux and come out this morning and the cruiser smells strong of gas inside. I wrote it off as coming from the tool bags i just pulled...

forum.ih8mud.com

There's a compound curve stamped into the tank, which can crack. Might be it

which one would that be on here?

 

[Godwin]

ok I'll go ahead and remove the fuel tank protector and see where the leak is really coming from.


which one would that be on here?

View attachment 2957581

In my case it was one of the large clamps on the fuel inlet hose. I don't recall how accessible the hose is without dropping the tank. I had expected a ruptured tank and had drained and dropped the tank in preparation to replace it only to find a loose clamp.

 

[avdeveloper]

You spent a lot of the searching other places for leaking fuel tanks.

Search this forum for a fuel tank leak and you'll find that these tank have a tendency to crack in one place.

The only other possibility is that your fuel hoses are leaking.

Remove your 2nd row seats (8 bolts) and remove the fuel pump cover from

In my case it was one of the large clamps on the fuel inlet hose. I don't recall how accessible the hose is without dropping the tank. I had expected a ruptured tank and had drained and dropped the tank in preparation to replace it only to find a loose clamp.

that must have been a relief. it will be similar to mine once I take a look. thanks all!

 

[TomH]

This is literally 30 minutes to check, an hour if you're slow.

Using the @BILT4ME time adjuster that works out to about 1.5 hours to 2.5 hours.

 

[Outsane]

There is an opinion that clogged charcoal canister can cause the crack, by not letting the tank vent properly.

 

[BILT4ME]

that must have been a relief. it will be similar to mine once I take a look. thanks all!

If it's a cracked tank you can drive it, you just don't want to fill past 3/4 tank. I drove mine for a year until I got a clean replacement, then prepared to swap.

Make sure you run it very low on gas before you start to replace because you'll need to drain the tank completely before you drop it. There is a drain plug.

 

[OffRoadScott]

If it's a cracked tank you can drive it, you just don't want to fill past 3/4 tank. I drove mine for a year until I got a clean replacement, then prepared to swap.

Make sure you run it very low on gas before you start to replace because you'll need to drain the tank completely before you drop it. There is a drain plug.

I am in the same situation as @BILT4ME I am still driving mine with the leak. I think of replacing the factory tank with a LRA tank but $2100 is steep.