14
REV. 03/2015
4. Adjust the oil seal in the groove to rectify it in place.
The tools shall be with no sharp edges and
corners, otherwise may easily damage the oil
seal!
DO NOT attempt this repair operation without
proper training!
2. Replace oil seals of big cylinder.
Failure symptom 1 : After the big piston rod is lifted,
it is lowered rapidly.
Failure symptom 2 : After the big piston rod is lifted
under no load of light load, the-
re is no obvious sign of lower-
ing, but it is lowered rapidly
under heavy load.
Cause: Damaged big piston seal.
Troubleshooting: Replace the big piston seal.
i
The big piston seal is of open structure.
Removal of big piston seal can roughly be divided
into three steps, as shown below:
Replacement procedure:
1. Remove the big piston rod fi rst, as shown in Figure
①
, it can be directly pulled out;
2. Loosen the guide bushing with a wrench, as sho-
wn in Figure
②
until it is thoroughly removed;
3. Remove the big piston seal from the guide bush-
ing, as shown in Figure
③
.
HYDRAULIC SYSTEM
