HELI CPC 20, Manual

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8.8.2 Inspection of wheel brake
Inspect all parts to make sure if there's any worn or damaged part. If necessary,
repair or replace with new one.
(1) Check the operating cylinder body's inner surface and the piston periphery
surface for rusting. Then, measure the clearance between the piston and cylinder body.
Specified clearance: 0.065mm-0.150mm;
Maximum clearance:0.15mm.
(2) Visually check the piston cup of the operating cylinder for damage or
deformation. If necessary, replace it.
Outer dia. of cup: 30.1 ;
-0.2
Cup interference: standard: 1.52mm; minimum: 0.42mm.
(3) Check the operating cylinder spring for free length. If necessary, replace it.
Specified free length: 60mm for 2 ton trucks; 58mm for 3-3.8 ton trucks.
(4) Check the friction piece for thickness to see if it is excessively worn If
necessary, replace it.
Specified thickness: 7.2mm for 2 ton trucks; 8.0mm for ton trucks;
Minimum thickness: 5.0mm for 2 ton trucks; 6.0mm for ton trucks.
(5) Check the inner surface of brake drum for damage and excessive wear. If
necessary, replace it.
Standard inner dia. of drum: 310mm for 2 ton trucks; 314mm for ton
trucks;
Max. inner dia. of drum after repair: 312mm for 2 ton trucks; 316mm for
ton trucks.
(6) Check the shoe return spring for free length and setting load (See Fig.8-16
and part No.6 on Fig.8-2, part No.7 on Fig.8-3).
Free length: L=106mm for 2 ton trucks; L=115.1mm for ton trucks;
Setting length: L=116mm for 2 ton trucks; L=122mm for ton trucks;
Setting load: 246N for 2 ton trucks; 225N for ton trucks.
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