I actually had to get back in there recently to reseat the pump gasket. I was getting a lot of raw fumes and finally realized the gasket had pinched out a little bit on installation, of course it was just a few minutes to fix it. I did however decide that I am going to do a flange and gasket around the cut...... someday....
I recently replaced the fuel pump on my 2001 Yukon XL 1500 from
the inside. I made an access hole with re-attachable cover. I
only had to remove the 2nd row bench seat and pull the carpet
back(no cutting of carpet required). I used a low depth cutting
wheel, fairly easy, the entire job took me a few hours. Replacing
the pump is easy at this point and self explanatory. Notice the
weld spots above the cutout. There is a stiffener welded under the
floor so the top of the cutout is about 1/2 inch below the welds.
The width of the cutout is 12 inches. See pictures.
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I figured I would add where to cut on a Suburban (this is a '99 GMT400).
I used a sawzall and dropped the tank as far as it would go without disconnecting anything. I just undid the straps at the bumper end and lowered the tank with a floor jack using a chunk of plywood to protect the tank. I had a few inches of clearance, but those small hoses near the bumper end were pretty close. A nibbler would work great.
There is a crossmember in there to cut through. I bolted in a steel bar to replace the chunk I cut out. I also laid a large chunk of plywood to protect the hatch when I'm running a load or the kids are jumping around in there.
I've done that on other parts replacement on my cars. Can't get to it cut things out of the way.
Good write up! iv been debating weither to do that or not.