JLG GRADALL 522D Owner's/Operator's Manual page 130

Se c t ion 4
Asse m bly a nd I nst a lla t ion
2. Lubricate internal brake housing surfaces, inner
and outer piston surfaces and oil seal bores with
SAE 90 oil. Figure 4.53.
Figure 4.53
MEDIUM
OIL SEAL
INNER
PISTON
SMALL
OIL SEAL
OIL
SAE 90
NOTE
Each piston assembly has three different sizes of
oil seals: three large, one medium, one small.
3. Install medium oil seal into inner piston bore and
install the small oil seal into the outer piston bore.
Figure 4.53.
4. ONLY use a manual press to install inner piston
into outer piston. Be careful not to damage oil
seals. Do not force the inner piston assembly.
Figure 4.54.
Figure 4.54
MARKS
NOTE
Rotate pistons until marks are aligned. If inner
piston does not rotate easily, disassemble it and
find the cause. Figure 4.54.
40
OUTER
PISTON
LARGE
OIL
SEAL
PRESS
5. Install springs into bores in inner piston.
Figure 4.55. For brake with 12 springs, jump one
bore each three. Figure 4.55.
Figure 4.55
6. Install compression plate on piston. Correctly
align the fastener holes. Use marks on piston and
lock pin slot. Figure 4.56.
Figure 4.56
PISTON
MARKS
7. Apply pressure to the compression plate until it is
flat against the piston.
COMPRESSION
PLATE
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