Brush Replacement; Brush Block Assembly Repairing; Attaching Individual Brushes To Brush Retainer - Piper Navajo Chieftain PA-31-350 Service Manual

14-34. REPAIR PROCEDURE FOR INDIVIDUAL COMPONENTS.
14-35. BRUSH REPLACEMENT. Brushes are replacable when the "B" barrel rests entirely within the
block: for example. hen the aft end of the 3/16 inch barrel is flush with the aft surface of the block. Brushes
must be replaced when the aft end of the "B" barrel is recessed as shown in Figure 14-14. See Figure 14-14 and
paragraph 14-57 for modular brush assembly replacement.
CAUTION
Side loads on brushes should be avoided to prevent brush damage.
a. Remove the screws which hold the brush block assembly to the mounting brackets and remove
the brush block assembly.
b.
Remove the two assembly screws which hold the block together. These screws are located one on
the same side as the connector plug and one on the side directly opposite.
14-36. REPAIRING BRUSH BLOCK ASSEMBLY.
a. Discard the old brush retainer assembly.
b. Assemble the new brush retainer assembly to the other block by slipping the block from the
front of the retainer assembly over the brushes and then over the springs. Replace the two screws removed
in paragraph 14-35. b. This installation can be made only in this manner since the springs are of slightly
larger diameter than the brush slots in the block and must be fed into the cylindrical grooves provided.
c. Reassemble the brush block to the mounting brackets utilizing hardware removed in paragraph
14-35, a.
14-37. ATTACHING INDIVIDUAL BRUSHES TO BRUSH RETAINER.
a. Remove the brush retainer assembly per paragraph 14-35, b.
b. Compress the springs by pushing the brushes back into the brush retainer assembly and hold
them there by wrapping with rubber bands.
c. Mark the connector plug with respect to its orientation relative to the brush retainer assembly
block so that it may be removed and replaced in the exact same position.
d. Remove the four screws which hold the connector plug to the block.
e. Pull the connector plug from the block far enough so that the leads from the brushes to be
replaced may be unsoldered at the plug.
f. Unsolder the brush lead at the connector plug and unsolder the "B" barrel from the brush rod of
the brush to be replaced.
g. Now. remove and discard the old brush and spring.
h. Place new springs over the rods on the new brushes and insert through the holes in the block of
the brush retainer assembly. Compress the spring and hold in position with rubber bands.
NOTE
New springs and "B" barrels should always be used when replacing
brushes.
i. Place the "B" barrel over the brush rod and soft solder. The end of the "B" barrel should be flush
with the aft end of the rod. The barrel must be concentric with the rod and no solder is permitted on the
exterior of the barrel or rod.
Reissued: 9/23/80 ACCESSORIES AND UTILITIES
4 E20
NAVAJO CHIEFTAIN SERVICE MANUAL