I am having problems with my CJ7 passing the required EVAP smog test. It has a GROSS Evap leak. We smok tested the system and found smoke bellowing from the rear left corner (roll over and liqid check valve) area. I am going to get into it tomarrow. I have found a few sources for roll over valves but cant seam to locate the LIQUID CHECK VALVE any where.
anyone know where to find a replacement?, Are They Rebuildable? if so, How?
I've had mine apart due to curiosity during some sheet metal repair to the wheel well baffle. You might find it just needs a good cleaning. It is not all that different from a carburetor float. If liquid fills from the bottom (vent connections) the main body of the check valve floats to close the orifice on the top. Be careful dismounting it from the baffle. The plastic is old and can be very brittle.
I am not familiar with the CA Evap tests, but....I have a hard time understanding how this liquid check valve would change fuel vapor amounts since it operates as a 'normally open' valve. Check for a cracked plastic body, perhaps....as I mentioned it can be brittle.
One idea would be just to bypass the Liquid Check Valve altogether to see if the symptoms go away. Then you would at least have more information to determine if you need/want to replace it.
Next, I would check the vent hoses themselves for cracks.
For the smoke test, where do they pressurize the fuel system? Is there a safe way to emulate this while you check out the system?
I also took mine apart when I re-replaced my gas tank, and there's not much to it. I think I mostly cleaned it out (two or three decades of gunk and debris), but seems like there was a spring and maybe an o-ring that I replaced on general principle. Sounds like you got it under control, It's a PITA, but if you ever roll your Jeep you might be real glad to have a working check valve.
"We are all of us in the gutter...
Some of us are looking at the stars."
~ Oscar Wilde via Chrissie Hynde
An o-ring for the fuel sender fits the LCV perfectly. It's advisable to put a little Vaseline on it (per FLynes), as the cap is a pretty tight fit. The LCV tends to be brittle with age, so be careful taking it apart.