Roll Over Check Valve Leaking Gas

So, last month driving the 74 cj5 with 304, my roll over check valve started leaking some gas, dripping off it. So since it's original, I thought, ok time to replace that. So ordered the new aftermarket JLCV-1 check valve at 80 bucks after all said and done, all good right? So it seemed. Then a few days later, put some more gas in it, just above half a tank and it starts leaking gas! My question is , how is gas getting up in the valve at half a tank? Causing leaking and dripping raw gas? Checked charcoal canister, everything fine and clear on the line no gas there! Just at the roll over valve! So I ordered another one, which is on the way. All my hoses look good and secure, it looks like it's leaking gas right out of the top of the plastic. Maybe I got a reject, but baffling nonetheless!

 

Maybe if you roll the Jeep over, it will stop.

 

Check to see if there is more than half a tank of gas. Tank could be overfull. Also that valve is called a check/rollover valve.
Could be a bad part.

 

Is your new valve mounted some higher than the tank? It should be. If you fill you tank to the fill cap the fuel level could be approaching the roll-over valve and flooding it, especially if off level .
The valve should not leak itself at all. I would think if it was defective it would just fail in a roll over or flood the charcoal cannister if every thing is too full. .

 

Yes, mounted it in same place as the old one. Gas gauge seems pretty accurate. Haven't encountered any pressure in the tank when I remove gas cap. I'll see what happens when I put another new one in, could be defective! Thank's for the input!

 

How is your canister? Maybe the line to it is clogged or crimped. Maybe recently the tank was over filled recently and flooded the canister and is still working its way out. I would leave the fuel cap off overnight and see if it still leaks, if it does then disconnect the line from the top of the rollover valve and see where the fuel comes out. The EVAP system breathes through the canister and if it is plugged the vapors have to leave somewhere. Another thought is a possibility of the carb. leaking fuel out of the vent tube and into the canister and then back to the roll over valve.. Process of elimination.

 

Yeah, pulled the canister out, everything is dry up front, carb is a new rebuilt 2100 and works great no flooding. blew air through the line back to tank through the check valve, all good. Blew air through canister, no problem. Like I said, everything looks good and dry up front. Just the damn gas leaking at the the roll over valve. It stops leaking when I shut it off , and takes a little while to start leaking when driving. Actually ordered two more valves on line, found the Delorean valve for 33 bucks. We'll see ! Oh, I did find a little white plastic restrictor at the canister hose when I took it off, shined a light in the hose and got it to come out of the hose, has a pinhole in the middle of it, It's been in there for a long time, must slow down amount of air going to canister.

 

Their is the plastic restrictor, I took it out for now.

 

Could be vapor/condensation. Hot weather. Check for vacuum coming from the canister to the back. How much vacuum and is it connected to the proper port.
Is the port controlled by a temperature valve and is it working.

 

Was the restrictor right at the canister from the roll over valve. I don't remember that on mine. Unfortunately mine was cracked and thru it away, waiting for another substitute. Maybe removing that will help pull the vapors back up through the purge valve. Hope it solves the problem.

 

Yeah, I think the restrictor plugged into the port where the hose connects to the charcoal canister. looks like from age it just fell out in the hose. So it's only a two port canister, line from check valve goes to canister then other port hose goes to front on snorkel air cleaner, that's it, pretty simple, since it's a 74.

 

The only good explanation is the vapor hose and return line hose got switched. Could be why it leaks when running.
Need to verify the line and might take two persons.

 

The only lines that could have been switched are the ones coming from the two vent nipples on the side of the tank and those go to the bottom of the check valve. It's not like one side is the inlet and the other outlet and the other hose is going from the top of the valve to the canister, put it in just like the old one was there. I did leave that little restrictor out and drove it around this morning and not a drop of gas anywhere Yay! But, I am below half a tank now. It runs great and I like the idea of keeping the charcoal canister, and I'm even searching for a new one online and they are hard to find.

 

Glad you got it fixed though it still doesn't explain 100% why the fuel was there in the first place. Just keep an eye on when you fill up the tank.
I like the idea of the canister and wonder if there is an aftermarket replacement. Venting without fumes and rollover protection is a win.

 

Yeah, thanks for all the input!