Overview
The ZF 4642.109.018 PARKING BRAKE is a critical mechanical locking assembly designed specifically for the WG 150 Series transmission. This OEM genuine part engages a spring-applied, hydraulically-released mechanism that secures the output shaft, preventing vehicle roll-away when parked or during maintenance operations. Positioned within the rear housing section of the transmission, the parking brake interfaces directly with the driveline to provide positive locking torque. The SKU 4642.109.018 is manufactured to ZF’s original tolerances, ensuring reliable engagement and disengagement under heavy-duty industrial loads. When replacing this unit, it is essential to inspect the adjacent 4642101109: TRANSMISSION HOUSING for wear or damage that could compromise alignment.
Symptoms of Failure
- Vehicle Creep on Inclines: A worn parking brake fails to hold the transmission output shaft stationary, causing the vehicle to drift or roll on slopes even when the brake is fully applied.
- Audible Grinding or Clicking: Internal spring fatigue or disc wear produces metallic grinding or repetitive clicking noises during parking brake engagement or release.
- Hydraulic Fluid Leakage: Degraded seals within the brake piston assembly allow transmission fluid to weep from the brake housing, often visible as drips near the output flange.
- Inconsistent Brake Release: The parking brake may stick in the engaged position or fail to release fully, causing drag, overheating, and reduced fuel efficiency during operation.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4642.109.018 |
| OEM Reference | ZF 4642.109.018 |
| Material | Hardened alloy steel with friction lining |
| Weight | 4.2 kg (9.3 lbs) |
| Outer Diameter | 180 mm |
| Mounting Bolt Pattern | 6-hole, 120 mm PCD |
| Max Holding Torque | 2,800 Nm |
Compatibility
This parking brake assembly is primarily designed for the ZF WG 150 Series transmission. It is also compatible with the WG 180 and WG 200 series when used with the appropriate 4642301205: TRANSMISSION HOUSING adapter. Additional models that share this brake interface include the WG 120 and select WG 250 variants. Always verify the spline count and housing bolt pattern against your specific transmission serial number. For accurate identification, reference the 0730365125: TYPE PLATE affixed to your transmission housing. The brake assembly is secured using a 0631311009: GROOVED STUD to ensure proper torque retention under vibration.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4642101109 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4642301205 | TRANSMISSION HOUSING | Rear housing section for brake integration |
| 0730365125 | TYPE PLATE | Identification plate with serial number |
| 0631311009 | GROOVED STUD | Fastener for brake assembly mounting |
| 4642301168 | SCREEN SHEET | Filter mesh for hydraulic circuit |
| 4642301169 | SCREEN SHEET | Secondary filter element |
| 0636100621 | HEXAGON SCREW | Bolt for housing fastening |
| 4642301186 | SCREEN SHEET | Fine mesh screen for oil return |
| 4644106324 | SHIFT SYSTEM | Gear selection mechanism |
| 4644306598 | PLATE | Cover plate for shift system access |
