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How to change your fuel pump.

92891 Views 131 Replies 69 Participants Last post by  JesusOnSkates
This write up was done while I removed and installed my new fuel pump.

Step 1. Disconnect the negative (-) battery cable.

Step 2. Raise and SAFELY support your van with either jack stands or ramps. The higher the better, also note that it does help to raise both the front and the rear of the van.

Step 3. I reccomend that you drain the fuel from the tank unless you have a quarter or less. This can be accomplished with a hand siphon or pump.

Step 4. Remove the splash gaurd from the driveshaft side of the fuel tank. It is installed with four press in clips and multiple slip on clips. It looks like this.
Step 5. You will need to loosen the fill hose attached on the drivers side of the tank. There are two clamps on this hose. It looks like this.
Step 6. It makes it easier to disconnect the fill hose if you remove the retaining screws that hold the fill hose in place inside the fuel door.
Step 7. Break loose but DO NOT remove the drivers side retaining strap bolts, on most vans the bolts do not need to be loosened as they are set from the factory to allow the strap to rotate freely once the bolts on the opposite side are removed, mine were over tightened by the previous owner or their mechanic. There is a hidden 15 mm nut on top of the strap where it attaches to the chassis. I have a needle nose vise grip on it in this pic to show where it is. I used a 12" extension and 15mm socket and a 15mm wrench to loosen these.
Step 8. Break loose the driveshaft side retaining strap bolts but dont remove them yet.
Step 9. Now is the time to support the fuel tank. I reccomend the use of either a transmission jack or a atv/motorcycle jack for this as it greatly eases the process.

Step 10. The fuel lines and the vent lines should now be removed from the hard lines. the two fuel lines require the use of a 5/8 line wrench and a 3/4 line wrench. the two vents are simple pinch clamps that can be removed with a pliers. Removing the rubber lines for the vents is a bit easier if the tank is lowered a few inches.

Step 11. Now it's time to remove the wiring harness. The wires run across the top of the tank and over to the drivers side they then follow the "frame" rail forwards and are attached to the body near the transmission. Unplug the harness and remove it from its retaining clips. Once it is free from the clips feed it through the hole in the "frame" and set it off to the side.

Step 12. Remove only the driveshaft side strap retaining bolts and then turn the straps 180 degrees out of the way.

Step 13. Now slowly lower the fuel tank being careful to make sure nothing gets caught and causes the tank to fall.

Step 14. Now it is time to remove the fuel pump / sending unit assembly. I accomplished this with a brass drift punch. Use the punch and a hammer to rotate the lock ring counter clock wise until it lines up with the notches in the top of the tank.

Step 15. Next you will need to remove the assembly from the tank be careful with this so the strainer does not fall off in the tank and the float arm does not get damaged.

Step 16. To remove the fuel pump from the sending unit you will need to remove the wiring harness and then push the pump up towards the top of the unit and when you have clearance tilt the fuel pump outwards and then pull down on it to remove it.

Step 17. Replace the o-ring seal on the top of the tank with a new one.
Step 18. Installation is the reverse of removal.

I hope this helps someone out there with there fuel pump job. Feel free to make comments on this post so I can make sure my details are as accurate as possible.
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Being "That Guy" who researches every project to death before tackling it, along with the fact that most pics in this thread have evaporated, due to the "PeeBucket fiasco/debacle, I naturally have a few questions. The actual changing of the pump is well described and seems pretty straight forward, so my questions surround the cutting of a hole, the potential discovery of a plate and the possible ins/outs of dealing with it. The actual cutting of the hole and fashioning a suitable, cool, removable cover also seems pretty straight forward to me. Bear in mind that I have a 91, shorty cargo van, with TBI.

A) Any definitive answers, measurements and/or pics as to the proper location of a 10" X 10" hole? Most convenient would seem to be a measurement either for the center of said hole or the front, passenger side corner.
B) If a plate is found, can it be found before cutting the hole or dropping the tank?
C) Can said plate be removed without completely dropping the tank? The way it is fastened in place is not evident in the few pics left in this tread.
D) Is this plate really necessary, or can it be safely left off at the end of this job?
E) If plate is found, would it be appropriate to leave in place as a "safety net" while carefully cutting the hole and then removing it afterwards?

As a relative newbie here and to Astros in general, I hope it's OK for me to make a couple observations and/or suggestions. First, this seems like such an important topic (given it's already a sticky anyway) for fuel pump virgins, it would seem appropriate to update with either new pics or replacements of the missing pics of the important stuff. I'm fairly certain that if PeeBucket hadn't taken a poop on us all, and the missing pics were still intact, all of my above questions would likely have been already answered!

Thanks Folks,
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Thanks folks for the comments and pep talk! The initial impetus for cutting the floor was multi pronged:

1) It seems that most driveability and running issues point to a fuel pump issue, from reading here and other things I hear/read about fuel injected Chevy trucks. This led me to think this should be expected to be a fairly regular operation. From your comments, maybe my assumptions have been incorrect. I had been planning to replace the current pump with a higher quality AC/DELCO or Delphi pump as preventative maintenance, but maybe it's not necessary. The previous owner said it was replaced a year or so back, but I have no idea what brand was used and the tank was just a tad above empty when I bought the truck!
2) The other thing is that I constantly read that one of the best ways to ensure longevity of the pump is to keep a fair amount of fuel in the tank and given that I'm not living hand to mouth, it will likely always be over half full, so dropping it becomes more of a hassle.
3) At an old, sore and fairly broken 62 years old, working on my back, and especially the getting up and down, is not my favorite pastime! Plus there is "ALWAYS" at least one needed tool that I forgot to bring down with me!

I plan to drive this thing for most of the foreseeable future, or at least as long as I'm capable of doing gigs, playing my guitar and singing, and am simply doing all I can to minimize the efforts needed to do so!

Thanks All,
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Right on for #3! In my case, I rarely realize I'm missing two, "UNTIL" I've gotten up and back down for one of the two. :screaming: :banghead: I guess I'll give a pressure check and if all is OK, I'll just call it good for now!
Thank You Sir,
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