I did this on a 2003 Short wheelbase Trailblazer with the 18.7 gallon tank.
My vehicle had just turned 133,000. This was the Factory pump. It had not failed and I was NOT getting any fuel gauge problems.
I simply wanted to replace the pump now before it failed from age.... Preventative measure pretty much.
I bought a new AC Delco Pump with the level sender for about $270 and a new external fuel filter for about $22. Total about $327 with tax.
Drive vehicle as much as possible after low fuel light to get rid of as much gas.
I chose to lay thick plastic down (in ase of fuel spill) and raise the vehicle with car ramps. I also used wood on the ramps so that the metal ramps dont dig into the cement.
Pop the hood and access the fuse box. With the engine running pull the relay for the Fuel pump, within a few seconds the engine dies. Crank the engine a few times to relieve pressure.
Disconnected the negative battery terminal and then open gas cap.
Next step was to remove the cross bar that would be in the way for dropping the tank.
Using a short phillips screwdriver loosen the screw on the fuel filter. You also want to press in on the schraeder valve to release any pressure in the lines. Gas may come out of this if theres still pressure in the lines
here in pointing at the schraeder valve
Have a container ready to catch gas that will come out of the filter/line connections.
To disconnect the fuel lines- simply press in the clips (blue on the filter) and the other lines you simply squeeze. No special tools needed for these.
Note how the fuel filter is gone- and the lines are wet from gas that drained out of the lines
With my thumb and forefinger im pointing at 2 more lines that must be disconnected. one is at the top that may be partially hidden... you may miss it- so I figured Id point it out. I was using a flashlight to make sure I didnt miss any connections.
I then proceed to place a jack and a piece of wood under the tank for support-for when I remove the straps.
Then loosen the hose from the tank to gas filler tube. Using a small ratchet and 7mm socket
Loosen the straps using a size 15 socket, extension, and 1/2 inch ratchet.
Once the straps are removed- the jack/wood is helping hold the tank. You may have to jiggle the rearmost strap to get it to get out of the way, the front strap came right off.
I then dropped the tank a little... so that I could look around and see what electrical connections there are.
laying down in the rear by the driver rear tire- looking in between the coil spring and the red rubber stopper- there is an electrical connection.
remove this.. these are easily disconnected.
I dropped the tank a little more-- I was then able to pop my head from under the car and look at the top of the tank and see the power connection to the fuel pump.
In this picture-- I stuck my hand above the frame and with my other hand I snapped the picture. This is also an easy connector to undo.
We then lowered the tank more- and found 1 more connection... in this picture weve already removed the tank.
but it was one of those instances where the other person helping sees the 'hidden' connector and I quickly rush over to that side to disconnect it as to not cause damage to the wires. It was located on the rear right corner of the tank.
Yes.... I recommend a helper for bringing down the tank...
once the tank is down- I slid it out. though theres a module on the tank that was in the way and I had to turn the tank a bit to clear the frame. (if you have higher ramps you probably wont run into this).
Here is the top of my tank after 133,000 miles. Since this is a California Car... there is no rust whatsoever on the fuel pump module...
those of you in the rust belt are likely to find rusted pump modules.
I then used a vacuum to suck up dust and small rocks and debris from around the pump assembly. I also cleaned the area with a wet towel. THen I disconnected the fuel lines here... similar clips like on the fuel filter.
I then compare the old and the new pump. (note the fire extinguisher--- just in case).
Removing the ring that holds the pump in place is EASY. use a screwdriver or brass punch and hammer to hit the ring and get it to rotate loose...
Mine came off easily. Remember that metal on metal may create sparks-- and youre working on a gas tank full of fumes. I wrapped my tip with electrical tape to avoid metal on metal.
Once I removed the old pump- I compared it to the new one.
I was surprissed at how clean the filter was. Yeah there was some debris on the filter... but I was expecting ALOT more crud.
I also compared the tops of the pumps.
the parts numbers were the same on labels
I then looked in the tank and was surprissed at what I didnt see...
After 6 yrs and 133,000 miles.. there was very little debris inside. I used a turkey baster to suck up as much of the large particles as I could.
I then compare the level senders. they were identical on mine.
to put in the new pump....
You slide it in- and making sure its pointing in the right direction (theres a tab on the top of the pump assembly)
Make sure you have the new rubber o-ring in place and press down in the tops, its spring loaded.
the metal ring to fasten down the pump needs to be turned to fasten it into place. You have to apply enough pressure to compress the rubber oring.
Most people use the hammer/screwdriver method to put it in place.
(PLEASE READ THE NOTE ON THIS AT THE BOTTOM).... it may save you aggravation... I suffered so you wont....
Proceed to reconnect the lines at the pump assembly.
Reverse the procedure to put the tank back in. Use the jack to lift it. You may have to fiddle with the rear strap.
Make sure to reconnect the electrical connections and then lift the tank more and fasten the straps.Reconnect all the fuel lines and replace the fuel filter.
Dont forget to reconnect the filler neck hose.
Double check to make sure you didnt forget any connections.
Remove stuff from under the car.
I then reconnected battery and shifted into neutral and allowed the SUV to roll off the ramps. I then plugged in the relay and went to turn the key to start (without cranking) to prime the pump about 4-5 times.... I then proceeded to start the vehicle. it cranked for a bit.
Once i knew it was running- I turned off and disconnected battery and proceeded to clean the throttle body.
I then put in a gallon of fuel from my 1 gallon gas container. Went to gas station and refueled with 18 gallons.
I came back and got under car to make sure there was no leaks.
to ramp up and remove the tank- while taking pictures--- 45-50 minutes... being the 1st time Ive ever done it.
to put the tank back in and reconnect- about 20-25 minutes.....
I started at about 730 am and finished about 1:30 pm.... 6 hours.... so what happened?
once the tank was out- I took some time to clean the top area on the tank. I vacuumed that area.
I also noticed the new pump didnt have the clips for the connections.. I swapped them from the old pump.
Removing the ring was EASY.....
Mechanics and others on here say to put that ring back on--- use a screwdriver and hammer to put it back on.
I tried it..... then I had dad and I try it. We coudnt get it back on.
Now maybe we could have wacked harder............ but I thought of it this way.
The pump assembly could be damaged. We may accidently puncture the tank (expensive!!!), or damage the plastic on the top if the tank.
so we loaded the tank into the other car and drove around to Pep Boys, Kragen, Autozone, Napa, several other shops. No one sold the tool to put this back on. several shops also told us they would have used the hammer screwdriver method.......
In the end we drove to the local chevy dealer where I talked to a tech. I offered to pay him $20 to use the GM tool to turn that ring.
Since the owner was there... we waited for him to dissapear- I then left $20 on the seat- he drove the car to the back and a while later he came back with the ring fastened on.
All this driving around and waiting was a good 3+ hours.
Others say they can put that ring on without the tool....
But if you plan on doing this... make sure you CAN put it back on..... or buy the tool online (saw it for $80 online) or find a shop/dealer/tech/friend who can twist that sucker on for you.
To me.. that $20 was worth it. Better to have spent that $20-- than cause alot more damage- hammering on with the screwdriver. Why it wouldnt slip on? Maybe the new o-ring was bigger? Maybe we didnt use enough force? I tried adding a little WD-40 to help lubricate... but no go. Please consider the tool.