2003 Tahoe 5.3L FLEX :
Trying to disconnect the fuel lines at the two quick disconnects located at the leading edge of the plastic fuel tank.

First one is the 3/8 fuel supply.
It appears to have a pair of cream colored plastic ears that protrude outward from the connection.
I tried squeezing the ears with fingers and then with pliers.
Neither method compressed the ears enough to release the quick disconnect.
Perhaps there is a better method? I may be wrong in squeezing the ears.

The second is the 5/16 fuel return.
I do not see any ears sticking out past the connector.
I can see a blue rectangle that resides in the side of the connector but my fingers will not squeeze it.
Perhaps I am incorrectly attacking this quick disconnect?

Will you kindly advise me of each quick connector release method?
Fuel supply : ??
Fuel return : ??
I bought a set of Lisle fuel quick disconnect tools ,but I do not believe that they apply at these locations.
They appear to be squeeze methods rather than insert a tool to push out any finger tabs as is done at the fuel filter quick disconnect.

Top line is fuel supply. Plastic ears protrude, but do not respond to squeezing. Is the rust preventing squeeze?

Supply fuel line quick disconnect appears different from return fuel line quick disconnect.

This is fuel return. No visible ears protrude. Blue rectangle cannot be squeezed by my fingers.

I sprayed PB Blaster for 2 days of soaking with no result.

 

You have more problems than just trying to remove fittings. It is a squeeze type release but the rust is severe. I am assuming you are replacing the fuel pump and the rusted lines will be new but the big problem is the disconnect and the rust built up inside the fitting. The seal will be crap and the locking fingers will be crap and.......so on and so on. You may want to plan on new lines as well but of course is your call. I think there are also repair kits to use if you damage the fittings but I don't like to trust repair kits on fuel and brake lines.

 

I realize now what is missing. On the bottom part of the fittings there should be little feet sticking out that are the same color of the colored pieces up in the black fitting. You pinch the feet and then that releases the other colored pices inside and should allow for the removal but you can bet that rust build up is what is causing your problem. I see in the second picture down that the green feet are there. The rust is keeping it from working for sure. The ones without the feet may have to be pushed out with the kit you bought but then again, the rust is in the way.

 

Thank you for the feedback.
Based upon your input, it is my understanding that both disconnects are of the squeeze type release.
I was concerned that the return fuel line connector is missing the little squeeze tabs that should be sticking out; hence nothing to squeeze.
Perhaps I can get some pincher pliers to squeeze the visible blue rectangular squares on the return fuel disconnect.
That is my plan.

It was my experience that the fuel supply connector does not respond to squeezing due to rust as you wrote.

I read about cutting the two nylon fuel tubes ( supply and return) that originate from the fuel pump and then splicing in a repair .
I believe that Dorman has parts or Lines to Go company has a kit ($55).
Do not know if I have the geography to allow that repair, nor how effective the repair would be.

Considering : to drop the tank and replace the two nylon supply and return tubes which would come with new quick connect fittings.
Yes, I plan to replace the original supply, return and vapor lines with a stainless steel kit from FineLines Company $200. Fuel filter is a separate purchase. Does not include the two nylon tubes that run across the top of the fuel tank from the fuel pump.

I have not been able to undo the quick disconnect at the fuel filter (3/8" insert plastic tool ,no rust seen ) nor either of the FLEX fuel sensor fittings ( 3/8" and 5/16" quick disconnect: no rust seen there).
I read of many folks that experience same difficulty who sprayed PB Blaster and pushed on insert tool with pliers to force the insert tool.

Inserted Lisle white plastic tools (5/16" top, 3/8" bottom) into quick disconnect at FLEX fuel sensor: PB Blaster for 3 days. No rust seen here . FAILED.

Inserted Lisle yellow plastic 3/8" tool at fuel filter quick disconnect. Buried insert tool by shoving it in as much as possible with pliers and screwdriver as a pry bar. Tons of PB Blaster for 3 days. No rust seen here. FAILED.

 

When you are trying to pull the lines off I have heard that you need to twist a bit and sometimes remove quick disconnect tool and reinsert clocked a little differently.

 

+1
blow it out with compressed and spray with penetrating fluid..let sit. Most likely the rubber o-ring in the plastic fitting will pull out due to the corrosion.

this is more than surface rust...you should consider line replacement. you can buy new plastic fittings to replace everything...then use plastic to plastic or plastic to metal unions designed for fuel lines. available at a knowledgeable auto parts store.

 

Resolved the 2 quick disconnect fittings at FLEX fuel sensor and at fuel filter.
The plastic white Lisle inserts were of little value at the FLEX sensor disconnects. I spent several hours wrestling with the disconnects, used PB Blaster , rotated the white inserts, shoved inserts with pliers and screwdriver--> FAILED. After destroying the Lisle plastic insert, I bought $10 metal scissor disconnect tool at AutoZone. It worked in 20 seconds!
However, there was no room for the metal tool at the fuel filter. Used the yellow Lisle tool for hours, PB Blaster, spun it, wiggled it some more. Swapped to the white Lisle tool and same process for another half hour. With all my might and using an open end wrench as a pry bar to force the plastic insert tool inward toward the joint--> it finally released. Took 3 days using those tools.

I still face the two disconnects at the fuel tank leading edge.
I again sprayed PB Blaster and brake cleaner to address the deep rust within the collar joints.
I studied several videos of folks who disconnect these within a few seconds and understand the theory of how it should disconnect.
CarQuest sells replacement fuel tank nylon tubes /hoses as a set for approximately $140.
Takes 3 days to order at store. Pondering that route.

Purchased one nylon fuel tube/hose splice repair package at CarQuest $20 for the 3/8 inch fuel supply tube /hose .
Fuel line crimping clamps are extra $4. requires 2 , plus crimping tool $10.
Ordered the additional 5/16 nylon fuel tube / hose repair splice kit $20 : 3 days to arrive at store.

In the meantime, I plan to see if I can dissect the two rusty quick disconnects at the fuel tank leading edge that reside between the two nylon tubes/hoses and the two steel rusty fuel lines.
Perhaps a tiny pick can be inserted between the rusty fuel line and the plastic disconnect clip. Would like to pry it apart.

The internal plastic squeeze clips with the squeeze "tabs/ ears/ feet" appears to be readily available at the auto parts store.
If I am successful in dissecting the clip, I can avoid dropping the tank and avoid the choice of the $150 replacement nylon lines vs. the $60 worth of splice materials.

All new territory for me.
I do not know why the quick disconnects were invented. Nothing quick about them. Fuel hose clamps at $1.50 each would appear to be AOK.
Perhaps fuel clamps cannot withhold the fuel pressure of 50-60 pounds??

Thanks to the contributors for confirming my plight.
I did not know what reality was until I was successful in disconnecting the three disconnects plus what I am facing at the rusty joint connections.
Experienced voices helped me.

 

What an ordeal. And one we don't encounter in Arizona, the primary advantage of living here.

 

Same here in Oregon. No rust problems and I love it. I used to run shops in KC, Mo. and had to deal with rust there and hated it.

 

I started out in the rust belt of Ontario. Its horrible. vehicles are junk at 5 to 7 years old. Running new brake and fuel lines front to back are common repairs.

I bought a plastic fuel line forming kit. Its faster to just cut it out and replace. plastic is the cheaper alternative and will last the life of the vehicle. I don't like running rubber fuel line hose with fuel line clamps due to potential leaks. steel takes more time to install, costs more but you can bend it 90 degrees.