Gradall 534B (9020-7317) Service Manual - Manual (Page 132)

HOW TO TEST A CYLINDER
1. Set fork on the ground.
2. Disconnect the hose at the rod end of the cylinder.
Plug or cap this hose.
3. Actuate control to extend cylinder.
4. Observe the oil by-pass coming from the cylinder
port. (See A, B & C)
HOW TO TEST HYDRAULIC MOTORS
(Always check pump and circuit relief
valves before checking motors)
We recommend that hydraulic motors be placed on
a test stand to evaluate their efficiency.
HOW TO TEST HYDRAULIC
CYLINDER EFFICIENCY
(By-Pass Test)
One of the easiest tests is to observe the amount of
oil being forced past the piston rings inside of the
cylinder. The amount of oil which flows indicates
the condition of the cylinder.
A.
B.
C.
GRADALL
LOED MATERIALS HANDLER
534B
TESTING AND ADJUSTING
Oil flowing from open cylinder port indicates
worn piston rings, or worn “O” ring between
the piston and the cylinder rod.
Leakage indicates leaking head to barrel seal.
Leakage indicates loose or worn rod packing.
HYDRAULIC CIRCUITS
12