Repair Of Brake Assembly - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
7-79. REPAIR OF BRAKE ASSEMBLY.
a. Replace all parts of the brake assembly which are cracked or worn in excess of the limits given in
Table VII-I.
b. Pressure plate (8) and back plate (5) can be repaired in accordance with the following steps:
1. To remove the wear pads from either plate, drill out the shop heads of old rivets using a
0.218 inch drill and punching out the old rivets.
CAUTION
Exercise care to avoid damaging or enlarging the rivet holes.
2. Before repadding either plate, inspect it for cracks using zyglo or dye-penetrant method.
Replace plates which are cracked or dished 0.015 inch or more.
3. Install new wear pads using the proper rivets and rivet tools shown in Figure 7-33. which
can be fabricated from dimensions given by a local shop. Ascertain that the formed (shop) head of the rivet
is flush with or below the surface of the wear pad.
NOTE
After pad installation, check rivets for snugness. A slight
movement of wear pads is desirable. It should be determined that
a force of not less than 2 pounds or more than 100 pounds is
required to cause movement of pad.
A maximum of one crack is permitted in the shop head of a
tubular rivet, but it must not extend into the rivet shank. To
check rivets that appear unseated, insert a 0.0015 inch feeler gauge
between the disc and the pad. It should not slide past the rivet.
4.
After repadding, grind the wear padded sub-assembly to the thickness as shown in Figure
7-30.
NOTE
Wear pads must be ground flat to each otherwith assurance that the
minimum dimensions shown in Figure 7-31 are held. Not more than
25 percent of the rivet head shall be removed by grinding.(Refer to
Figure 7-29.)
c. Protective Coating. Treat newly ground back and pressure plates which are not being put into
immediate service as follows:
1. Degrease discs in a vapor degreaser to remove all oil and grinding residue.
2. Immerse disc in "Houghton's Rust Veto 377 or equivalent. Use in the as-received condition
without dilution. Let discs drip and air dry for five minutes or more. Clean, compressed air may be used to
help speed drying time.
Reissued: 9/23/80 LANDING GEAR AND BRAKE SYSTEM
2G7