Mack ASET AC, Service Manual

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Page 262
REPAIR INSTRUCTIONS, PART 1
290
Figure 290 — Rocker Arms
Rocker Arm Adjusting Screws
앫
The pressure oil fed adjusting screws are
Armolloy coated for resistance to galling and
wear
Pinless Valve Yoke
앫
The top inboard corner of yoke has been
chamfered at a 45-degree angle, necessary
to ensure clearance between yoke tip and
the heavier rocker arm casting.
291
Figure 291 — Pinless Valve Yoke
The revised rocker arm components described
above cannot be intermixed with previous version
components.
With the heavier rocker arms, it is mandatory to
use the pinless valve yoke having the chamfered
tip at the top of the inboard end.
Valve Rocker Arm Shaft
Disassembly (with/without Engine
Brake)
Refer to Figure 295, Figure 296 and Figure 298.
The shaft assembly is disassembled as follows:
1. If equipped with MACK PowerLeash™
engine brake, remove the solenoid from the
shaft.
2. Remove the C-clip and flat washer from one
end of the shaft.
3. Remove the outer rocker arm and spring
washer.
4. Press the mounting bracket from the shaft.
Use care not to drop the assembly as the
bracket is removed.
5. Remove the second spring washer, rocker
arm, flat washer and C-clip.
6. Repeat steps 2 through 5 to remove the two
remaining rocker arm sets from the shaft.
7. Remove the adjusting screws and jam nuts
from the rocker arms.
Changes to the rocker arm since January 2003
are significant; therefore, no components from
the current rocker arm shafts can be
interchanged with the non-current components.
1. Wider Casting at Nut
Flange
2. Revised Oil Passage
3. Near-Full Width Casting
4. Steel Bushing
1. Heavier Rocker Arm
Casting
2. Yoke with Chamfered Tip
5-111.bk Page 262 Monday, July 10, 2006 2:26 PM