Examination Of Wheel Brake - Yale A7S1 Service Manual

8000 YRM 2199
STEP 7.
Remove the shield for the wheel cylinder, remove
all the parts from inside the cylinder.

Examination of Wheel Brake

Examine all the parts for ware or damage. Replace
parts as necessary.
1. Examine the inner surface of the wheel cylinder
body and the surface of piston column for rust.
Measure the clearance between the piston and
cylinder body. Replace if necessary.
Specified Value:
0.065-0.150 mm (0.003-0.006 in.) (2-3.5T truck
only).
2. Check if the rubber cup is damaged or distorted.
Measure the diameter of the rubber cup to
confirm specified value of Φ30.1-0.2 (2-3.5T).
The standard value for interference of rubber cup
is Φ1.52, and the minimum value is Φ0.42
(2-3.5T).
3. Check the free lengths of the wheel cylinder
spring. Replace if necessary.
Specified Value: 60 mm (2.4 in.) for 2-2.5T and
58 mm (2.3 in.) for 3-3.5T.
4. Check the thickness of the brake shoes. Replace
if excessively worn.
Specified Value: 4.5-7.2 mm (0.18-0.28 in.) for
2-2.5T and 5.0-8.8 mm (0.20-0.35 in.) for 3-3.5T.
5. Check the diameter of the inner surface of the
brake drum to confirm specified value. Replace or
restore if excessively worn.
Specified Value: 310-312 mm (12.20-12.28 in.) for
2-2.5T and 314-316 mm (12.36-12.44 in.) for
3-3.5T.
6. Measure the free length and installation load of
return spring for brake shoes. See Figure 31.
Forklift Truck
Tonnage
106 mm
Free Length
(4.17 in.)
116 mm
Installed Length
(4.57 in.)
Maximum
246 N (55.3 lb)
working
Figure 31. Load return spring for brake shoe
7. Measure the free length and installation load of
return spring for top rod. See Figure 32.
Brake System
2-2.5T 3-3.5T
115.1 mm
(4.53 in.)
122 mm
(4.80 in.)
225 N (50.58 lb)
35