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Disassembly
1.Match mark housing (3, Figure 7-2), piston housing
(4), and cap structure (5).
The following procedure is necessary to properly
relieve the pressure exerted by the belleville
springs on the cap structure. Failure to follow this
procedure could result in capscrew failure and
personal injury during disassembly!
2. Loosen the 12-point capscrews (10, Figure 7-2)
evenly, in 20 ft. lbs. (27 N.m) increments.
a. Alternate the loosening procedure by selecting
successive capscrews located approximately
180° from the previous.
b. Continue loosening procedure until spring
pressure is released and capscrews and wash-
ers can be removed by hand.
3. Remove cap structure (5). Lift belleville springs (7)
out of piston (6) counterbore.
4. Lift piston/housing assembly off housing (3) dow-
els.
5. Remove springs (1), separator discs (12), and
friction discs (13).
6. Remove piston (6) from piston housing (4). Re-
move piston seals (8 & 9) and discard.
Cleaning and Inspection
1. Clean all parts thoroughly.
2. Inspect dowel pins (2, Figure 7-2). If pins are
grooved from excessive wear or otherwise dam-
aged, press defective pin out of housing.
3. Inspect compression springs (1, Figure 7-2).
Check springs for free height and test for height
under load. Replace if not within approximately
10% of specification.
Free Height:
. . . . . . . . . . . . . . . . . . 0.456 in. (11.58 mm)
Height @ 36.4 lb. (162N) working load:
. . . . . . . . . . . . . . . . . . . 0.350 in. (8.89 mm)
4. Inspect belleville springs for cracks or damage.
5. It is recommended the separator discs and friction
discs be replaced if wear is indicated.
6. Check piston and piston housing bore for
scratches, nicks, pitting or other defects than may
cause seal leakage. Slight defects may be re-
paired by polishing.
J7-4
Assembly
1. If dowel pins (2, Figure 7-2) have been removed,
press new dowel pins into holes in housing until
fully seated against shoulder.
2. Install a separator disc (12) over dowel pins. Insert
a spring (1) over each dowel pin. Insert a friction
disc (13). Insert springs (1) over dowels.
3. Install another separator disc, the 2nd friction disc
and the remaining separator disc.
NOTE: The internal teeth of the two friction discs must
be aligned and must be concentric with the pilot
diameter machined on the rear of the housing to
enable the completed assembly to be installed prop-
erly. If available, a mating gear as installed on the
wheel motor rotor shaft (4, Figure 7-1) should be used
to simplify alignment.
4. Assemble the seals (8 & 9) on the piston.
a. Install O-ring seal in bottom of each groove. Be
certain O-rings are not twisted.
b. If available, use an expander to expand the O.D.
of each seal enough to allow it to slide onto
piston.
NOTE: If an expander tool is not available, the seals
may be heated to 400°F (204°C) MAXIMUM. This will
allow ring to be manually expanded until it will fit over
piston.
c. When each seal is over the groove, re-size by
compressing the seal ring. Use a full circle
clamp with any sharp edges or grooves cov-
ered to prevent damage to the seal surfaces.
d. Install the quad ring in each seal.
5. Lubricate the piston seals and insert piston (6) into
piston housing (4).
6. Install piston/housing assembly over dowels on
housing (3).
7. Place belleville springs (7) in piston counterbore
as shown in Figure 7-2.
8. Place cap structure (5) on assembly and insert
capscrews (10) with hardened washer (11). Do
not tighten capscrews.
The following procedure is necessary to properly
compress the belleville springs. Failure to follow
this procedure could result in capscrew failure and
personal injury during assembly!
Parking Brake
J07010 12/98
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