Dropping the fuel tank

Cut an access port in the hatch area for changing fuel pump. It will save so much time.

Here's a site with a pic of the cut spot so you will do the job right.
Fuel Pump Replacement on F-Bodies - MEASUREMENTS - Worldisround photo

pneumatic sheers

fyi dropping the tank on a 20 year old car is damn near impossible without some kind of incident like snapping brake hard-lines. i would never drop the tank unless absolutely necessary. trap door is good!

then is there a way to change the fuel pump without dropping the tank or cutting into the floor? i really don't want to hack up my car for something that gets done once every 20 years. i'd much rather drop the tank than cut into the unibody structure.

That's the nice thing about freedom, there's always choices, and in the end, you do the job how you feel it should be done.

BLK95TA said:

then is there a way to change the fuel pump without dropping the tank or cutting into the floor? i really don't want to hack up my car for something that gets done once every 20 years..

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nope, you're stuck with those two options

if do a clean job of the trap door thing like everyone else does, you'll never see it again, since it's under the carpet

i hear ya about sheet metal mods on a unibody car, i usually wouldn't, but the size of hole you're cutting isn't exactly in a stress zone. if it was, everyone that had a trap door would note ovaling on the screw holes over time, and they dont.

you're cutting metal which will leave bare metal exposed and you could be causing rust issues down the line. my floorboards are rust free and i don't think i'd want to go cutting metal and leaving exposed metal that could very easily start rusting later.

When I cut my trap door, I primed and painted the exposed bare metal in the factory color. There goes the rust problem.

If you do a nice job it can look like a factory install. Many cars today have holes in the trunk to access the fuel pump.

More importantly, I have this lovely blind faith that GM knew that a solid one piece piece of steel between driver and gas tank was a good idea. I know, you can RTV it etc etc, but not the same as a solid non cut floor panel. IMO of course.

I have dropped the tank every time I have done a pump, and its always been on the driveway. Never removed the rear end to get the tank out, nor touched any brake lines...

i wouldn't have any faith that GM would do this as a structural thing; those guys can be really lazy.

steveo said:

i wouldn't have any faith that GM would do this as a structural thing; those guys can be really lazy.

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hence that blind faith part

Structurally yea, its not gonna hurt, but if theres a fire, I would rather have a solid wall of steel between me and flammable fluid.

ShowNoMercy said:

hence that blind faith part

Structurally yea, its not gonna hurt, but if theres a fire, I would rather have a solid wall of steel between me and flammable fluid.

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Ditto. i don't want to be driving a 300hp ford pinto :lol:

I always figured, if you have a fire and the gas tank blows, that little bit of extra intact metal won't keep you from doing a Richard Pryor impersonation.

For those too young to know- he caught himself on fire and went running down the road that way.

It's not like you're leaving an uncovered hole in the trunk.

Mystery Bird said:

It's not like you're leaving an uncovered hole in the trunk.

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Unless you weld it back shut, its still structurally deficient compared to OEM.

I really don't see why its proclaimed as so hard to drop the tank. Right up there with optis don't last long and LT1s are slow.

Im not to worried about structural issues as this cars getting fitted with a cage and the frames are already tied together. i haven't started bracing mounting brackets yet but that's on my to do list. That link for the fuel tank trap door is a gigantic help. Ill see if i can fab up a new door that can remain sealed when i am driving or at the track.

The metal that needs to be cut is very soft and you can do it in a few minutes with ordinary snips. Try to round off the corners to avoid having weak points at square corners. I used a bunch of 1/4" Tinnerman nuts to fasten the cover, which was 1/8" aluminum and overlapped by about 8 inches on all edges. I also placed a sheet of thin vinyl under the hole and above the tank to insulate it a bit. And, of course, put back the original rubber sheet on top. This was all done at least 6 years ago and when I opened it up last month to check the EVAP pressure sensor, I noticed no rust.