Suburban Sending Unit Access Hole
 

To read the original thread and discussion on this topic go here- LINK

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Well, I decided to bite the bullet and cut an access hole in the rear floor of the Suburban to get to the fuel sending unit. It actually worked out very well. The measurements are taken from the wheel tub bolt on the left side of the first picture. (Pic #1)
http://67-72chevytrucks.com/vboard/a...hmentid=921086

Draw a line from that bolt to the corresponding bolt on the drivers side wheel tub. ( the top of the picture is toward the back of the truck) I used my skill saw to cut the sides then used the Tool Box Saw to finish out the corners. (Pic #2)
http://67-72chevytrucks.com/vboard/a...hmentid=921087

I set the saw depth to exactly 3/4". I didn't trust the depth setting on the saw so I used a piece of 3/4" wood to set it. (Pic #3 ) (make sure it is unplugged!)
http://67-72chevytrucks.com/vboard/a...hmentid=921088

The wires are fairly close to the bottom of the floor so I slid a piece of 1/4" plywood in between the tank and the bottom of the floor as a safety buffer. I cut the 1/4" plywood 12 x 24 inches and slid it in from the rear of the tank. (Pic #4)
http://67-72chevytrucks.com/vboard/a...hmentid=921089

After cutting the hole, removing the piece, and sliding the 1/4" plywood back I saw that it was almost perfectly located. (Pic #5)
http://67-72chevytrucks.com/vboard/a...hmentid=921090

I then scraped around the sending unit with a small pick to loosen up the dirt and other crud and used the air nozzle to blow it all away. I guess you could also use a vacuum cleaner and suck it up if you didn't have a compressor. I squeezed the spring hose clamp with my small slip joint pliers and slid it up toward the sending unit to get it out of the way, then used the pliers to turn the fuel line hose back and forth to break it loose from the metal tube. After working the rubber fuel line off of the metal tube and unhooking the fuel gauge wire I sprayed the top of the unit with PB Blaster and let it soak for a few minutes before tapping the lock ring off. (Pic #6)
http://67-72chevytrucks.com/vboard/a...hmentid=921091

The black cruddy looking stuff is undercoating. Lift the sending unit up (you may have to turn it a little to get the metal tube past the floor) and tip it sideways to lift it out. You have to get the filter sock out first then work the float out. It should come out without forcing anything. (Pic#7)
http://67-72chevytrucks.com/vboard/a...hmentid=921092

I was lucky because my ground wire was long enough to get the unit out without cutting or unsoldering it.

To trim the hole out I bent up 4 metal trim pieces as shown in the picture. (Pic #8)
http://67-72chevytrucks.com/vboard/a...hmentid=921093

Which I will screw to the floor with 3/4" long flat head wood screws. I then set the piece of wood that I cut out down into the metal trim to finish it out. (Pic #9)
http://67-72chevytrucks.com/vboard/a...hmentid=921094

I don't know if all of the suburban tanks are in the same location or not so do your own checking before cutting the hole...:)

LockDoc