IV-104
HYDRAULIC UNITSCYLINDERS
INSPECTION AND ADJUSTMENT
Inspection after Disassembly
Clean each part thoroughly with cleaning oil, then
carry out the following checks. When a cylinder has
been disassembled, replace all the seals with new
ones.
Piston Rod
• Replace the rod if there are cracks.
• If the threads are damaged, repair them or replace
it.
• If the plating layer of the plated portion is broken,
rusted or scratched, replace it.
• If the rod is bent more than the limit of 1 mm in
1 m, replace it. (Measure by the method shown in
the figure at right.
If the bending of the rod is within the above limit,
yet is bent a lot in a small distance so that it won·t
move smoothly, replace the rod if it makes a
squeaking sound in the operation test after reas-
sembly or if it catches during movement.
• If the inner diameter of the clevis bushing is worn,
replace the bushing.
Tube
• If there are cracks in the welded portion, replace
it.
• Replace the tube if the inside surface is scratched
or if it leaks hydraulic oil.
• If the inner diameter of the clevis bushing is worn,
replace the bushing.
Rod Cover
• If the bushing inner diameter is worn and the
clearance with the piston rod is greater than 0.25
mm, replace the bushing.
• If the inside surface of the bushing is scratched,
and the scratches are deeper than the depth of the
coating layer, replace the bushing.
Measuring the Bend
a. Support the portion of the rod with the same di-
ameter at both ends on V-blocks.
b. Set a dial gauge at the center between the two
blocks.
c. Rotate the rod and take a reading of the maximum
and minimum runout indicated by the dial gauge.