Parking Brake Caliper Repair
1800 SRM 1037
1.
MAXIMUM DISC THICKNESS
2.
MINIMUM DISC THICKNESS
3.
ORIGINAL DISC THICKNESS
Figure 4. Disc Maximum Wear Limits
Table 1. Disc Wear Limits
Original Disc
Thickness
Maximum Disc
Wear
Minimum Disc
Wear
12.7 mm
(0.5 in.)
1.5 mm
(0.06 in.)
9.7 mm
(0.38 in.)
20 mm
(0.79 in.)
1.5 mm
(0.06 in.)
17 mm
(0.67 in.)
Caliper Parts
1.
Inspect the piston, housing bore, and O-ring for
scratches or corrosion. Remove small scratches
or corrosion with fine emery cloth. Replace the
components if there are large scratches or exces-
sive corrosion.
2.
Measure the diameter of the piston at the large
and small end. Replace the piston if the large
end diameter is less than 101.47 mm (3.995 in.)
or the small end diameter is less than 63.37 mm
(2.495 in.).
3.
Measure the diameter of the housing bore at the
large and small end. Replace the housing if the
large end is greater than 101.68 mm (4.003 in.)
or the small end is greater than 63.63 mm
(2.505 in.).
4.
Inspect the housing for damage. If damage can-
not be repaired, replace the housing.
5.
Inspect springs for wear and damage. Always
replace springs as a set.
6.
Inspect the threads of the spring cap for damage.
If damage cannot be repaired, replace the spring
cap.
7.
Inspect the stud and threads on the stud in the
piston. Replace studs if damaged.
8.
Inspect the lining fasteners for wear or damage.
Replace worn or damaged fasteners.
ASSEMBLE
WARNING
Use only specified components when assem-
bling the caliper. Do not use components from
other calipers. If the wrong components are
installed, the caliper will not operate correctly
and can cause damage to the equipment. Use
of parts not approved by Hyster can cause
damage and loss of braking which could result
in serious personal injury.
WARNING
Take care when using Loctite
®
to avoid seri-
ous personal injury.
Follow manufacturer’s
instructions to prevent irritation to eyes and
skin. If Loctite
®
gets into eyes, flush them with
water for 15 minutes. Have eyes checked by a
doctor as soon as possible.
CAUTION
Use a vise with soft jaws in the following step
to prevent damage to the caliper piston.
1.
Apply Loctite
®
277 or equivalent to the threads
of the stud. Using a vise with soft jaws to hold
the piston, install the stud into the piston.
2.
Lubricate the piston outer diameter and ring
groove, housing bore and ring groove, new
O-rings, and backup rings with Dow Corning
®
DC4 or with the type of hydraulic fluid used in
the system.
3.
Install new O-rings and backup rings in both
the piston groove and housing groove so that the
curved side of the backup ring is against each
O-ring. Verify the O-ring on the piston is closest
to the disc. In the housing the O-ring goes closest
to the spring cap. See Figure 5.
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