Tahoe 2003, 5.3 liter FLEX :

Trying to remove the two 15 mm fuel tank strap bolts.

Lots of rust.
Both bolts are spinning carefree , but not backing outward.
Are there supposed to be nuts welded somewhere on top?

I am trying to wedge a screwdriver between the frame and the small sliver of space that now appears between the fuel tank strap and the frame.
I am hoping that I can cause the bolts to catch a thread and back out.

Removed rear tire driver side to see what is visible at the frame area.
There appears to be a free spinning nut in the rear strap bolt frame area.
Hope I can get an open end wrench in there to hold the spinning nut.

How to handle the possible free spinning nut in the front fuel strap area?
There is no tire to remove to gain visibility.
What are the options?

15 mm fuel tank bolt head - free spinning ,but not back out.

View inside rear driver tire well zone. I can see a nut that spins inside / above the frame. Hope to grab this hex nut with wrench. How to handle the front fuel tank strap 15mm bolt. No visibility/ access to possible spinning hex nut inside the frame.

 

You may have to make a tool by getting the correct size box end and then bend it to shape needed to reach in there. Have to heat the wrench to do that. Rust causes so many problems and I hate rust. Living in Oregon, there is no rust. May have to torch the bolt head off to get strap off and then can snake a bolt back in there from inside that frame area and weld in place from the other side of the frame.

That is a captured nut in the frame and after years of rust they break free.

 

or cut the strap...remove the tank and have plenty of access to remove the bolt and speed nut

 

Good call. This can work as well if not better.

 

Gentlemen, thank you for your guidance.

I was successful in grabbing the rear driver side hex nut that resides within the frame structure.
Removing the tire was key to seeing the hex nut spinning through a small triangle hole, just enough room to slide an open end 15mm wrench.
Constant angular pressure on the wrench to keep it forced onto the internal hex nut was necessary to avoid the wrench from slipping off the hex nut .
The small access hole made it almost impossible. Took 2 hours to complete the extraction of the rear 15mm tank strap bolt from the free-spinning nut.

Your input encourages me to attack the front 15mm fuel tank strap bolt from a different approach.
As I understand your guidance, it would be possible to cut the 15mm bolt head off, thus allowing the fuel tank strap to fall off.

Once the tank is lowered, you feel that I will have access to the hidden 15mm nut that should have been immobilized within the frame.
That is wonderful news.
I was afraid that the frame rail would cover the front hex nut.

Please confirm that this is true.

I do not have power tools, compressor, lift , etc.
I am working under the jacked Tahoe on wooden 6x6 blocks in my driveway.
Day 14 of doing this job! Nothing comes apart as it should.
The videos make it seem so easy . All is rusted and seized and cemented together.
Nearly every step has been super difficult.

Until the fuel tank is removed ( fuel lines already out) , I am queasy about any electric stuff near the gas fumes.
If I can get this bolt/nut defeated, only have to disconnect electrical fuel pump plus one vapor pipe retainer clip .

The bolt my need to be sawed /split/ cut by my hand labor.

Here is info that may help others with spinning hex nuts at fuel strap bolts.
Website : https://gmtnation.com/forums/threads...lt-spins.8979/
It discusses the rusted spinning nuts and says that they are called : F- clips.
F-clips can be obtained through GM ( hefty, beefier) or from Dorman.

 

Disconnect the vehicle battery NOW !!!

I recommend real jack stands.

 

Resolved.
Thank you for your wise words.
Cutting the strap was the best choice for me as the bolt head was buried and I dared not use a grinder near the fuel tank.
I noticed that the rear strap had a narrow neck on the hook side vs wide neck on the bolt side.
The same anatomy was on the front strap , so I cut the narrow hook side of the front strap with a hacksaw.
Took exactly one hour.
Hats off to you. Thank you.
I believe that I may now gain access to the spinning hex nut/clips.

Yes, battery was disconnected and fuel pump relay removed when I started fuel line removal. Good advice.