I need to replace my sending unit on the side tank (aux). do I need to drop the tank to do this, it looks like you can get at it. also does it come out easily(sending unit). I have never done this before. I found a sending unit at LMC for 69.99 for a side tank, there were no other sending units for 73-79 so I am assuming this would be the right one to use, thanks.

 

AKBG,
The tank should be dropped.
The sending unit generally is installed from the top of the tank to avoid leaks. There is a metal slide ring that cinches the sending unit in place. This is generally rusted to hell. A bunch of scag and dust will accumulate as you take a hammer and screwdriver or chisel and tap the ring CCW to free it. The ring may shift to one side or the other and become jammed. Shift to a new tab with the chisel and continue to tap away. Get a shop vac and suck all the rust and dirt away before you remove the sending unit. You may have to rotate/twist or turn the sending unit to get it out. Remember your path out because its your same path back in. The filter only goes on one way, so that's no issue, replace the filter while you have the chance. Clean the tank out as best you can. I usually siphon out the crap with a large fuel line and filter it through a T-shirt so I can pour the fuel back in afterwards.
Good luck,
KingFisher

 

I've never done it, but it looks like the sending unit will come right out the side of the aux tank. Looks like the only thing that could be in the way is the drive shaft. But like I said, I've never done a aux tank - the rear main tank HAS to be dropped to change the sender.

Let us know what you find.

Marty

 

I just recently replaced the sending unit in 79 f-150. I was able to r&r the sending unit without dropping the tank. You just have to be patient about getting it out past the drive shaft.
John

 

thanks for the info. My rear gas tank has a leak at the seam, I plan on dropping that one out first since I do not use it and practice taking out the sending unit on that one on the ground, this way when I try and do the one on the side I will know what I can expect. where did you get your sending unit? I have not seen the side one anywhere but LMC.

 

Took the rear tank out and found out where it was leaking, and patched it up with quick steel. I tried to get the sending unit out but the 3 tabs just dissolved as I hit them. I gave up and decided to just put the tank back in. the sending unit now works! and it does not appear to be leaking either! I plan on hitting the aux tank sending unit with a hammer shortly to see if I can move the sending unit, maybe that will get it working as well, If I cannot get if off. I may just leave it as long as the back unit works. I like when things work out! I does not happen often. thanks for the advice, its appreciated.

 

You probably had a bad ground.