Center Support Assembly: Reassembly
- Lubricate all moving parts with ATF. Install new oil seals and "O" rings on center support hub, sun gear shaft and brake piston. Lubricate "O" rings and install No. 2 brake piston into center support. Use care not to damage "O" rings.
- Install 12 return springs into position on piston, then place retainer onto return springs. Compress return springs and install snap ring. Repeat procedure for No. 1 brake piston.
- Install No. 1 brake plate, disc, and then chamfered backing plate with chamfer facing disc. Install No. 1 brake snap ring into center support with ring end gap between openings on center support. Fig 1
On brake No. 2, install thrust disc. Alternate friction discs and plates to match positions as disassembled. Install chamfered backing plate with chamfer facing disc.
Courtesy of ISUZU MOTOR CO.
- Install No. 2 brake snap ring. In Volvo applications, BW 55 models use .055" (1.4 mm) snap ring on No. 2 brake while AW 55 models use .047" (1.2 mm) snap ring which has blue marking to identify it further. End clearance between snap rings and discs on both brakes should be .012-.048" (.30-1.20 mm). Fig 2
Courtesy of VOLVO CARS OF NORTH AMERICA.
- Check operation of No. 1 and No. 2 brake pistons by applying compressed air to oil holes. When air is applied, distinct clicking should be heard as piston is activated. Fig 3
Courtesy of ISUZU MOTOR CO.
- On Isuzu applications, install dial indicator so tip is resting on backing plate. Apply compressed air and record piston stroke as measured on dial indicator. Piston stroke should be .026-.051" (.65-1.30 mm) for No. 1 (front) brake and .037-.068" (.93-1.7 mm) for No. 2 (rear) brake.
- If stroke exceeds specification, clutch pack is excessively worn. If stroke does not meet specification, clutch components have been incorrectly installed or too much ATF was applied to clutch plates and discs.
- Install brake hub assembly on sun gear with cupped side facing splines of sun gear. Install 1-way clutch on sun gear shaft. Check that 1-way clutch is not loose or stiff when installed on shaft. Check 1-way clutch by holding No. 2 brake hub and rotating sun gear. Sun gear should rotate counterclockwise but lock up if clockwise rotation is attempted.
- Install 1-way clutch and sun gear shaft into center support. Align grooves of brake hub with lugs on discs. Install ring on sun gear shaft in groove on splined portion of shaft.