1.88 HYDRAULICS DUAL BRAKE VALVE (MICO) - Servicing NOTE: Not all models use spring (18**). Some models also use a 6.35 mm (0.25 in.) spacer with shims. Make sure the same number of shims, and spacer, that were removed during dismantling are installed. Assembly Use a repair kit when assembling the valve, the repair kit contains a new cup, boot and O-rings. 11. Install new boot (23*) on housing (15). Before assembly, lightly lubricate the parts from the repair kit and the spools and sleeves with clean hydraulic oil. 12. Test the brake pressure at service hose A on brake valve. Pressure can be adjusted by adding or removing shims (17) to retainer assembly (16).
Make sure all parts are clean before assembly. 1. Install a new cup (13*) in spacer (14) and one new O-ring (10*) on spacer (14). Note direction of cup. 2. Install new O-ring (10*) on sleeve (11) and new O- ring (7*) on sleeve (8). 3. Carefully install spool (12) into sleeve (11). Note direction of spool. 4. Install spacer (14) into housing bore through end plug (4) end of housing. Note direction of spacer. 5. Carefully install sleeve (11) and spool (12) assembly into housing bore using a wooden dowel. Note direction of assembly. 6. Carefully install sleeve (8) into housing until it rests against sleeve (11). Carefully install spool (9) into sleeve (8). Note direction of assembly. 7.
Install spring (8) and retainer (5) into housing bore. 8. Install end plug (4) and torque load to 10.9-20.3 Nm (96-180 lbf/in.) to seat sleeves. Then loosen end plug ј turn and torque load to 1.1-6.0 Nm (10-60 lbf/ in.). Install new O-ring (3*), washer (2) and nut (1). Hold the end plug (4) with a wrench and torque load nut to 68.1-81.4 Nm (50-60 lbf/ft.). 9. Install retainer assembly (16) in housing. NOTE: Depress retainer (16) until it bottoms on spacer (14). Spools (9 and 12) and retainer (16) should return when released. If the spools and retainer do not return when released, the bore of sleeves (8 and 11) may be damaged. 10.
Install shim(s) (17), springs (18**), (19), (20) and piston (22) in housing bore.