1.86 HYDRAULICS DUAL BRAKE VALVE (MICO) - Servicing NOTE : Up to Machines S/No.51200471 only. 9. Remove O-ring (10*) and cup (13*) (note orientation) from spacer (14). Remove O-ring (10) from sleeve (11) and O-rings (7*) from sleeve (8). Servicing is normally restricted to the replacement of seals. When the bore of the cylinder or the piston is scored, the brake valve must be replaced. NOTE: Take care not to damage cup or O-ring grooves or bore. Dismantling 1. Make sure all the blanks are secure in the ports then clean any dirt off the assembly before dismantling. 2. Remove boot (23*) from piston (22). 3. Remove piston (22), springs (18**), (19), (20) and shims (17) from housing bore. NOTE:
Some models also use a 6.35 mm (0.25 in.) spacer with shims. Note the number of shims removed from housing. 4. Examine bearing (21) for wear or damage, only remove if necessary. NOTE: Excessive wear on bearing (21) and piston (22) require replacement. 5. Remove retainer assembly (18) from housing bore (a ball bearing is pressed into the retainer). 6. Loosen nut (1) and remove end plug (4) from housing. Remove spring (6), retainer (5), nut (1), washer (2) and O-ring (3*) from end plug (4). 7. Use a wooden dowel to remove spacer (14), sleeves (8) and (11) and spools (9) and (12) assembly from housing bore. This assembly must be removed through end plug (4) end of housing. NOTE:
Take care not to scratch or mark sleeves (8) and (11) or housing bore. Sleeve (8) and spool (9) also sleeve (11) and spool (12) are matched pairs and must not be mixed with other parts. Excessive wear on sleeve or spool will require replacement. 8. Separate spacer (14) and spools (9) and (12) from sleeves (8) and (11).