Midwest RDH Repair Procedure

The Midwest RDH handpiece is fairly common and is used by hygienists to clean teeth.
The most common problems for this handpiece include a bad prophy head or a dirty
motor. Both of these problems can be easily solved. As always, try to determine the
problem before disassembling the nosecone.
Some signs to look for are:
• The Motor is locked up:
o Try removing the prophy head and running the motor. If the motor now
runs freely without the head, simply replace the prophy head (Part# SO-
720445). If not, disassemble and overhaul.
• There is little or no torque when the motor is running:
o You may have a cracked drive gear at the top of the nose section, or you
may have a dirty motor in need of overhaul.
• The nose section spins when the motor is running
o This is a sign of a faulty prophy head, simply replace the head.
The repair procedures for each of these problems is addressed below
STEP 1
To remove the nose portion from the motor portion, secure the nose
assembly approximately ¾ up the shaft. Use about a ¾" collet to hold the
nose. Then wrap the motor housing with a strip of rubber and gently wiggle
the housing while simultaneously pulling up. This will allow the two pieces
to work apart.
You can now see the retaining clip that was holding the two pieces together. Try to be
careful with this clip as it is hard to replace.
Midwest RDH Handpiece
Repair Procedure
STEP 2
Remove the two
pieces and set
them on your
work surface.