The gauge sender is often glommed up after years of crud in the tank. It’s an
easy fix that I’ve written up several times. You can do this with a pair of big
channelocks, you don’t have to have a 36mm socket.
Here’s the archive of it:
https://web.archive.org/web/20020311143203/http://www.mbz.org/info/articles/fuel_system/fuelsender.html
Ful text:
Tools Needed:
36mm Socket
8mm socket or wrench to remove seat back bolts Lots of clean shop towels or
rags.
Plenty of room around car for seat bottom and back to clear doors while
removing. Fuel tank as low as you dare to go with it.
Procedure:
1.) On a 126 and some 123 chassis cars: Remove rear seat bottom by releasing 2
red clips on forward bottom edge of seat frame. Pull to one side on the clips
while lifting up - you'll feel the seat frame come up as soon as they release.
Lift up on the forward part of the seat bottom and pull towards the front of
the car. Carefully remove seat bottom from car. On most 123 chassis cars the
sender can be accessed through the first aid kit box on the parcel shelf. Check
your car before yanking anything out!
2.) In the center of the seat back below the armrest is an 8mm screw. Remove
it. On either side at the lower corners of the seat back are metal brackets
with 8mm screws in them. Remove these as well. Climb into the center of the
back seat area and lift the seat back straight up. There's a metal lip on the
back of the seat that hooks on two "ridges" just below the parcel shelf. Lift
the seat back off of these and carefully set it down in the back of the car.
CAUTION: Use two people for the next step!!
3.) With another person's help lift the seat back and remove it from the car.
Why two people? Because if you try to do this yourself the seatback is too
heavy. You'll end up dragging one of the corner brackets across the top of the
wheel well or somewhere else around the door area. I have the scars to show for
it. Now is a good time to apply some Leatherique to the seat back and bottom
while you have the whole thing out.
4.) After wading through the spare change, candy, Cheetos, etc, you'll find
some black insulating/sound deadening material draped down the back of the
seating area. On the left rear (driver's side) there will be a cut-out just
below the parcel shelf. Carefully pull this portion back. underneath is a large
(3"-4") diameter plastic plug. Pry it out of the opening it seals.
5.) You are now looking at the top of the guage sender. Carefully remove the
electrical connector and move it out of the way. Place your socket on top of
the sender and turn it counterclockwise. Once unscrewed all the way, get ready
with some shop rags/towels.
6.) Carefully and SLOWLY lift the sender assembly out of the hole. As you lift,
fuel will be draining out of the cylinder. There are two holes in the side, one
near the top, another near the bottom, with still a third in the base. Look
down into the tank as you get close to the bottom of the sender or listen
carefully to tell when the fuel has stopped draining from the sender. Have some
towels or rags ready, as when you remove the sender from teh tank there will
still be fuel dripping from it. Be patient! Too many of us have pulled the
sender out prematurely and gotten baptized with #2 diesel. Yuck! Take the
sender to a clean work area where you can disassemble it and lay the parts out.
7.) Start by wiping the outside of the sender with a clean towel. You'll be
amazed at the nasty black stuff all over. get used to it -you're going to see
more . . . On the bottom of the cylinder is a small round "nut". Carefully
unscrew this with a pair of pliers and put it aside. Gently twist on the bottom
of the sender and it will start to come apart. Be prepared for more fuel!
Here's what you will find:
A.) Flat metal disc that covers the bottom of the plastic plate and acts as the
"floor" for the maze.
B.) Plastic disc that is the closure plate for the bottom. Lots of convoluted
grooves in it, like a little maze. Make sure these are cleaned out, as they act
as a damper for fuel to flow in and out of the sender cylinder.
C.) Outer tube of the sender. Two small holes in the side, both should be open
and unclogged. These allow fuel to flow in and out of the sender so the float
will register properly. The inside will be messy as well. Clean it. I pass
paper towels (or better yet, a non-fuzzy shop rag) through it.
D.) Sender float and guide rod/wires. Here's where the fun begins
8.) Clean all the individual pieces, saving the float/guide rod assembly for
last. You can use any number of solvents for this, just use them in accordance
with proper safety practices. My cleaner of choice is an electrical contact
cleaner.
9.) Take the float/guide rod assembly and carefully clean it, using a cotton
swab or something appropriate. Handle it carefully, as the fine copper wires on
the sides are very important as you will discover! On the bottom is a
