Changing Fuel Pump Sending Unit

MountaineerTom · November 12, 2003

Guide posted here for people to have access to until they get posted in the appropriate section here at GM-TC.

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Changing the Fuel Pump's Sending Unit

This guide covers changing the sending unit on the fuel filter of a 1999 Chevrolet S-10 Blazer. While not all procedures will be the same, they will be similar for S-10 trucks and full-size trucks/SUV’s.

Here’s a look at the parts that come in the kit from GM.

Park the vehicle in a place where you’ll have plenty of room to work. If you have access to a lift, that would be great. We didn’t, so we just backed the vehicle’s rear tires up on some ramps. Having the least amount of fuel in the tank helps too; less weight to deal with. Also, if you have a truck, it may be easiest to remove the bed from the truck rather than lowering the fuel tank. Obviously we couldn’t do that with the Blazer, but after doing by removing the tank, I have to believe that removing the bed would be easier. Once the bed would be removed, you would have access to the fuel pump right on top of the tank without having to lower it. Removing the bed would be fairly simple too; removing the bolts that hold the bed on, removing any electrical/ground wires that are connected, and having a few extra bodies to help lift and carry the bed to sit on stands or saw horses. If you do remove the bed, it would be wise not to sit the bed directly on the ground. While it doesn’t weight a lot, it could be just enough to cause the sheet metal on the sides to bend.

Relieve any fuel pressure by removing the fuel cap. Disconnect the negative battery terminal. Pre soaking any required bolts/nuts with WD-40 prior to the job will help also. We removed what lines and connectors we could from the fuel pump and tank but it’s tight in there and we couldn’t get them all at that time. There are 3 lines and 2 electrical connectors to be removed from the fuel pump, and the filler and vent hoses that need to be removed from the back of the tank. There was also a small hose on the front part of the tank that needs to be removed, but we didn’t see it until we actually started lowering the tank. Just remember where everything hooks back up. Label the lines, if needed.

Start by removing the skid plate, it equipped.

Once the skid plate is off, you’ll have access to the straps that hold the fuel tank on.

The forward strap on the Blazer was pretty rusted and not very stout. It was basically formed as a strap that ended in a threaded bolt. It was not coming off easily in our case and ended up breaking trying to remove it. We supported the tank with a floor jack with a transmission removal assembly on it.

We easily fixed the broken strap problem by welding a bolt to the strap.

Once all the straps were loose, we lowered the tank just enough to get better access to the lines and connectors leading to the fuel pump. This is where removing the bed of a truck would make the job so much easier. There is not much room to get in there, at least on a Blazer. If you had the bed of a truck off, it would only take a couple minutes to remove the lines. In our case it took an hour or so of messing with it.

See Part Two

k1500chevy97 · November 13, 2003

This will come in handy I need to change mine on the 97

mblrds · November 29, 2003

Approximately how much does the bed weigh minus tailgate?

M.

boutbroke · July 2, 2004

Thanks Mountaineer Tom, U-da-man. I'll review these pics and then decide about taking the bed off. Normally that would be my option but I have a full toolbox and gooseneck hook-up in my bed.

The gooseneck ball is not a problem but there are two spring loaded u-bollts for safety chains that will have to be removed.

As far as the other question from mblrds about the weight of the bed minus tailgate. I would guess 150 pounds. My son and I have picked one up and set it further back on the frame for painting. It is really manageable with 4 people, one on each corner.

snoman · July 2, 2004

As far as the other question from mblrds about the weight of the bed minus tailgate. I would guess 150 pounds.

I would peg it at least twice that amount at the minimum and would guess between 400 and 500 pounds minus tail gate is more realistic and possibly even more.