BRADEN PD12C Series Installation Maintenance And Service Manual page 13

TROUBLE
A
The hoist will not lower the load or
not lower the load smoothly.
B
Oil leaks from vent plug.
C
The brake will not hold a load with
the control lever in neutral.
PROBABLE CAUSE
1. Friction brake will not release as
a result of damaged brake discs.
1. Same as A2.
2. Motor seal may be defective as
a result of high system back pres-
sure or contaminated oil.
1. Excessive system back pressure
acting on the brake release port.
2. Friction brake will not hold due to
worn or damaged brake discs.
3. Brake clutch is slipping.
13
REMEDY
A. Apply 1000 PSI (6,900 kPa) to
the brake. Close shut-off valve and
let stand for fi ve (5) minutes.
B. If there is any loss of pressure
in fi ve (5) minutes, the brake cylin-
der should be disassembled for in-
spection of the sealing surfaces and
replacement of the seals. Refer to
"Motor Support-Brake Cylinder Ser-
vice".
Disassemble brake to inspect brake
discs. Check stack-up height as
described in "Motor Support-Brake
Cylinder Service".
Same as A2.
System back pressure must not ex-
ceed 150 PSI (1,035 kPa). Inspect
hydraulic system for a restriction in
the return line from the control valve
to the reservoir. Be sure control
valve and plumbing is properly sized
to hoist motor.
Oil analysis may indicate contami-
nation has worn motor shaft and
seal. Thoroughly fl ush entire hy-
draulic system and install new fi lters
and oil. Install new motor seal.
The same as Remedy 2 of Trouble
B2.
Same as Remedy 3 of Trouble A3.
Improper planetary gear oil may
cause the brake clutch to slip. Drain
old gear oil and fl ush hoist with sol-
vent. Thoroughly drain solvent and
refi ll hoist with recommended plan-
etary gear oil listed in "Preventive
Maintenance".
Brake clutch may be damaged or
worn. Disassemble and inspect
brake clutch as described in "Brake
Clutch Service".