Form No. 81-460-044 Revised 2017-04-17
(3)
MICO, Inc.
FIGURE 1
Figure 1a
Items included in Repair Kit
Not used in all models
SERVICE DIAGNOSIS
(Refer to Figure 1)
BRAKE WILL NOT RELEASE
1. Inoperative valve assembly (8)
2. Piston (20), plunger (13), washer (14)
binding
INSUFFICIENT BRAKES
1. Broken pressure regulating spring (18)
2. Boot (21) damaged, allowing dirt to
accumulate under piston (20) flange
BRAKES WILL NOT RELEASE
COMPLETELY
1. Piston (20) sticking
2. Plunger (13) sticking
EXCESSIVE BRAKING
1. Too many shims (19) installed in valve
NO BRAKES
1. Plunger (13) or piston (20) stuck
2. Broken spring (18)
ACCUMULATOR CHARGING CYCLE
REPEATS FREQUENTLY WHEN BRAKES
ARE NOT BEING USED
1. Poppet (42) leaking
2. O-ring (44) leaking
3. Valve assembly (8) not seating
4. Pilot valve ball (33) leaking
5. Seals (4 & 9) leaking
ACCUMULATOR CHARGES FREQUENTLY
WHILE BRAKES ARE BEING HELD
1. Seal (12) worn
2. Seat on plunger (13) damaged
ACCUMULATOR STARTS TO CHARGE
BUT DOES NOT REACH HIGH LIMIT
1. O-rings (29 & 30) on pilot valve body
inoperative or damaged
2. O-ring (52) on charging valve spool (53)
has been damaged or worn
ACCUMULATOR CHARGING TIME
TOO LONG
1. Broken charging valve spring (50)
2. Charging valve spring (50) has taken a set
3. Dirt in filter (46)
4. Poppet (42) stuck, partially closed
ACCUMULATOR FAILS TO START
CHARGING
1. Broken pilot valve spring (26)
2. Broken charging valve spring (50)
3. Charging valve spool o-ring (52)
inoperative
4. Charging valve spool (53) stuck
5. Dirt in filter (46)
VERY RAPID CYCLING OF CHARGING
VALVE
1. Pilot valve (31 & 32) worn
