Ford Truck Enthusiasts Forums - Ford Bronco (1989-1996) fuel pump replacement

This was done a couple of months ago so forgive me if I'm not as through as I usually am. At that moment I was heading home right after pouring some engine flush in the engine oil... When all of the sudden the engine died, my first thought was "OMG, I messed the engine up!", but after several hours of inspection and tries to turn the engine it became clear the cause of the failure was fuel starvation (the engine would turn but wouldn't fire at all). So I found myself a new Motorcraft fuel pump and replaced the dead one, this write-up is a guide on how to make this as painless as possible if you haven't crafted an access latch in the cargo area.

I had the truck towed home and parked it the best I could, so it was on even terrain and well positioned to be worked on. As always, wear eye protection (specially since you'll be working under the truck and believe me, you don't want any debris falling in your eyes), disconnect the battery, and take all the safety measures required.

Tools used (Required ones in bold):

- Fuel siphon pump (or any effective mean to retrieve any fuel remaining in the tank, you do not want to handle that extra weight).
- Fuel container (jerry cans or any other mean to handle the old fuel, usually it is recommended to refill the tank with fresh fuel, the particles in the old fuel might hurt the new pump
- 2 Jackstands.
- Jack (or any other mean to safely lower the tank)
- Socket wrench set (sizes 1/4", 6mm, 14mm, 15mm deep socket, 3" extensión bar)
- Combination wrench set (it needs to be the size of the bolts holding the nuts found on the tank shield, probably 13mm) You will be using either this or a second socket wrench to lose the nuts/bolts in the shield
- Fuel line disconnect tool (a cheapo metal scissor type will do just fine)
- Phillips screwdriver
- Flat screwdriver

Well, there isn't really too much to this, so these are basically the steps you need to follow (I will of course describe everything in detail with each picture):

- Siphon the fuel from the tank
- Lift the truck for easier access, in my case 3" where enough
- Support the fuel tank, a floor jack will do nicely, just make sure to center it properly
- Remove the tank straps (mine didn't have them, I wonder where they ended... Useless mechanics!)
- Remove the tank shield and lower the tank, just enough so you don't put any tension on the fuel lines or the pump plug
- Disconnect the fuel lines and plug and remove the tank from under the truck
- Open the tank and retrieve the fuel pump assembly
- Replace the fuel pump/pick-up screen
- Reverse the previous steps to finish the procedure

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This is how I lifted the rear of the truck and placed the jackstands, it made for a little more headroom, and it will make sliding the fuel tank out easier.

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This hand pump came in handy ( :D ) to extract the fuel, pumped some then let it work alone for a while, as it has been the tradition the last times I've had to work on the fuel pump, there where almost 3/4 of fuel remaining in the tank... Once while pumping one of the extremes became deattached, spraying a bunch of fuel right in the face of a friend, it was actually quite funny :-X04.

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Disconnect the fuel tank from the filler neck, to do so just loosen up the clamp (seen in the pic) joining the rubber hose to the filler neck, then open the fuel door and remove the 3 6mm bolts holding the filler neck, this will make re-attaching everything back way easier.

Since my tank straps got lost along the way long ago, I will skip that step, but my guess is there will be 2 bolts/nuts holding each strap, remove those.

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This is the fuel tank shield, notice the big grooves where the straps fit against the shield, this is the rear side showing 4 nuts. There are a total of 8 nuts/bolts holding it in place, once those come off the tank will fall, so make sure it is properly supported, I didn't do it and half the thing fell on my chest.

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Using the combination wrench this way will make your life a lot easier, just turn it with the socket wrench until it gets stuck against the chassis, locking the bolt in place while you take the nut out.

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Here is where the 15mm deep socket and 3" extension become handy, the comb. wrench locks the bolt in place while the deep socket loosens the nut, I was unable to use a normal socket because of the length of the bolt, and even though a comb. wrench would have worked too I would have been quite a bit slower using that.

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Setting up the new fuel pump: here on top is the pick-up screen, it comes separated from the pump but it's easy to set. The screen comes with a rubber ring, just slide that over the pump and push around the edges of the ring until it seats properly in place, it will be quite tight. In the back you can also notice the in-tank filter or sock, that one goes attached to the plastic body of the pump assembly, again, remove the old one and push this one in place.

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This is the top of the fuel tank, you need to disconnect both lines, pull the safety clips to remove them, now unplug the lines using the scissor tool, to do so push each line against the tool and the fuel pump, then pull away to release them. Disconnect the feeder plug also, this should make the tank free so you'll be able to slide it out.

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With the tank outside, remove the ring holding the pump assembly in place. It's a big ring that resembles a castle nut, and will be all around the top of the assembly, just tap on it counter clock wise with a punch until it releases and turns. In this pic the ring is off, and you can see (barely) the groove it fits on. Also shown is the slim hose used to release the gas fumes from the tank, remember not to let this one off, nor let if be obstructed in any way during reinstall, trapped gas fumes can cause a lot of trouble and be very dangerous, mine was crushed against a top strap and it released a lot of pressurized fumes every time I opened the tank, in case of a rear-end crash that could have easily cause a fire, even a static charge spark could make that ignite. I always make sure to ground myself before going anywhere near the fuel door, just touch the truck's steel body to release any charge before going anywhere near the fuel tank.

Once the pump is out it could be a nice time to clean the fuel tank, both inside and out, and maybe even paint it if you see it fit. Since my tank was in great shape I just cleaned the outside and washed the inside with solvent and fuel until there was no more dirt/rust coming out.

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With the pump assembly outside the tank, you can get to the pump, these 3 bolts (1/4" I think) hold the float, disconnect the red cable and take the float off. Be very careful of how everything is connected, check the condition of every cable, and since smartphones are awesome, take some pictures to guide yourself with the re-assembly if you think you can have any problem later on.

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Another view of the assembly (the float is still on).

You need to access the plastic body in order to replace the old pump, to do so: Remove the float, disconnect the 2 cables remaining (pump feed), pull the metal cap apart from the plastic body (the 2 pipes coming inside the plastic body will come out), remove the plastic body cap (pictured next), replace the pump and the in tank filter, reassemble the fuel pump assembly.

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This is the cap of the plastic body, once you remove it you'll be able to remove the fuel pump. To do so you'll have to undo the plastic clips all around the body to release it, this requires some patience, not brute strength, don't break any of the tabs/clips (a small screwdriver might come handy here). Once the body is open just replace the pump and place everything inside back in the same way it was, this should be a pretty straightforward job. My cap was a little bent as shown in the pic, I didn't cause this during the removal and among other things (like dirty fuel) this could have helped with the pump's failure. Luckily I kept the previous fuel pump plastic body and that cap was nice and straight so I was able to reuse it.

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Reassemble the fuel pump assembly and reinstall it back in the tank. With this the pump is rebuilt and should work fine once again. Here you can see the old cap on the newer plastic body, it worked like a charm.

The reassembly procedure of the fuel delivery system is pretty much the reverse of what has been done so far. In the same note, reinstalling the fuel tank is also pretty much the reverse procedure of what has been done, slide it under the truck, reattach the fuel lines and pump feeder plug, lift the tank and shield in place, install the straps and filler neck back, refill the tank and go for a spin. If you suspect the fuel you syphoned out was dirty/bad dispose of it or save it to clean parts and get fresh fuel, now you can go for a spin. Don't worry if the fuel meter isn't giving a proper reading, once the float fall in place everything should work fine once again.

Congrats! you just finished replacing the fuel pump of your Bronco! now you're ready to get back on the road! :)