Saturday, September 12, 2009

Accordion Bass Mechanism Repair Part 2

Accordion Bass Mechanism Repair Part 2

After you have built your jig to hold the
accordion bass button/rods, you can
proceed with the disassembly of the bass
mechanism. Before I start, I position the
accordion on a table, supported by a couple
of pillows, with the edge of the keyboard
away from me, and resting against some
sort of support to prevent it from slipping.

A couple of large spring clamps attached to
the edge of my table work well. You will
need a small jewelers screwdriver, and a
long nose pliers for this. If you can obtain a
“Bass Button Straightening Tool”, it may
come in handy to straighten any crooked
buttons. Also some masking tape, a pen or
pencil, a small straightedge, some cleaning
cloths, a bottle of “goo be gone”, some Q-
tips, and some small containers or baggies
for the screws you remove. A small
flashlight also comes in handy.

First, you must obviously disengage the
Bass Strap from the knurled adjusting nut
by spinning the nut until the threaded end is
free, and then moving the strap aside and
out of the way.

Then you must remove the
bass mechanism cover by removing the
appropriate screws. Make sure you mark
these screws and place them in a small
container in a safe location. Once the cover
is off you can see the Bass Mechanism

On older accordions there may be a
lot of dust and debris loose on the bottom. I
make sure there are no essential pieces
lying loose in there, and then I take my
vacuum cleaner and gently vacuum out any
obvious dust or debris. You may notice
“greasy” or “sticky” debris on the bass
button rods. Don’t worry about that now,
we will clean all of that up later.

The first set of Bass button rods you will
remove are the Diminished and 7th chords.
To do this you will have to remove the
“retainer” which holds them into their guide
slots at the bottom of the rods. Usually this
is a thin strip of wood held in place by four
small screws. Before you do anything,
mark the retainer with a pencil in some way
so that you know how to orient it when you
reinstall it. I usually put a letter “R” on the
right side.

Remove the screws, mark them
appropriately and place them in a small
container in a safe location. Remove the
retainer and set it aside.

Now the first set of rods is available for you
to begin to remove. Starting at the far right
side, with the bass button rods nearest the
air release button, remove the first rod by
gently sliding the bottom of the rod out of
the guide, and then gently lowering it until
the button is free of it’s hole up above.
Carefully withdraw the rod from the
accordion and being sure not to bend it.
These rods are made of aluminum and will
bend easily. Examine it for cleanliness and
straightness. Put a few drops of “Goo Be
Gone” on a cloth and clean the rod to
remove any grease or dust. Hold the rod up
against the small straightedge to see if it is
straight along it’s axis of movement. If it is
bowed at all, gently straighten it and then
place it into your jig in the appropriate
location. Follow the same procedure with
the remaining 39 bass buttons from the
Diminished and 7th chord locations.

More in Part 3.


  1. What an undertaking! Have you ever thought of modifying the watchmaker analogy into an "accordionmaker" analogy? Considering the great complexity you find in the accordion.

  2. You obviously must have a lot of patience and esteem for the instrument as well!
    Great job.

  3. Is there any chance of putting the rods back if they get all mixed up?