What else should I change while I'm dropping the tank?

[Madbomber88]

I am about to tackle replacing the rusted out tailpan and drop my gas tank to replace the sending unit on my 91 K5. The gauge says 3/8 full when the tank is empty, so am I thinking correctly the first place to start is the sending unit? Any reason while I am there that I should replace the gas tank and the fuel pump? Just figure now's the time to do it while it is all apart.

Where's the best place to get a qualitt fuel pump? Also, did 91 K5s only come with the 31 gallon option? I can't find it saying it had a 25 gallon tank anywhere.

Appreciate the help!

 

[dyeager535]

First off I'd try fixing the sending unit. Quick test of gauge is to disconnect the wiring plug to the tank, turn the key to "run" and ground the wire on the vehicle side of the plug that goes to the gauge, and make sure the gauge responds correctly. If it doesn't change reading, then the sender isn't the problem.

If it does respond, then yes the sender is likely at fault. There has been a "fix" written up on this board before, but its very simple. Super fine steel wool, small torx bit (can't recall size, prolly 10 or less) and simply cleaning off the metal windings underneath the plastic cover that is held on with the torx bits.

The great thing is that you can test the sender once you clean it to see if the gauge responds right, without putting the tank assembly back in. I cleaned mine, it made the gauge MUCH closer, but still not exact. That's ok though, as the senders are expensive (IMO) and if you know where full/empty are on the gauge, your good to go.

The internal tank baffle may have broken, that could be part of the issue with the gauge reading.

Quality fuel pump, stick with AC Delco. No one will argue that is your best bet for an internal pump for a stock application.

Best place for tanks, check lmc truck or gastanks.com. Different size tank depths have been posted on here as well. Make sure you get one that is baffled. ('87-91 applications only)

 

[gaspass]

A shackle flip is much easier with the tank down.

 

[Skigirl]

Replace the sock while you're in there.

 

[spearchucker]

The sock came with my AC Delco pump and I think it was about $50. I'd replace the filter too. If you haven't already changed the body mounts and are thinking of it then this is the time since you can get to the 2 near the tailpan.