Overview
The ZF 4642.109.429 PARKING BRAKE is a critical mechanical locking assembly designed specifically for the WG 150 Series transmission. This OEM genuine part engages directly with the output shaft to secure the vehicle when stationary, preventing unintended movement on inclines or during loading operations. As a spring-applied, pressure-released mechanism, it ensures fail-safe engagement if hydraulic pressure drops. The SKU 4642.109.429 is precision-machined to ZF’s exacting tolerances, integrating seamlessly with the TRANSMISSION HOUSING and the TRANSMISSION HOUSING to maintain structural integrity under heavy loads.
Symptoms of Failure
- Vehicle Creep on Slopes: When the parking brake fails to hold, the vehicle may roll forward or backward on inclines, indicating worn friction surfaces or broken return springs within the 4642.109.429 assembly.
- Audible Grinding or Clicking: A metallic grinding noise when engaging or disengaging the parking brake suggests damaged splines or debris contamination, often linked to a failing GROOVED STUD that secures the actuator.
- Hydraulic Fluid Leaks Near Output Shaft: Leaking transmission fluid around the parking brake housing points to degraded seals or a cracked piston bore, compromising the brake’s ability to release fully.
- Intermittent Brake Release: The parking brake may stick or release slowly due to corrosion or galling on the sliding surfaces, often exacerbated by a missing or damaged TYPE PLATE that misidentifies service intervals.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number (SKU) | 4642.109.429 |
| OEM Reference | ZF 4642.109.429 |
| Material | High-strength alloy steel with corrosion-resistant coating |
| Weight | 4.2 kg (9.3 lbs) |
| Max Torque Capacity | 1,200 Nm |
| Operating Pressure | 12-18 bar |
| Dimensions (L x W x H) | 180 mm x 120 mm x 95 mm |
| Seal Type | Nitrile rubber (NBR) O-rings |
Compatibility
This parking brake is primarily engineered for the ZF WG 150 Series, but its mounting pattern and spline configuration also suit the WG 180 and WG 200 models when paired with the correct SHIFT SYSTEM adapter. It is not recommended for WG 120 or WG 250 variants without verifying output shaft dimensions. The 4642.109.429 integrates with the PLATE that aligns the actuator piston, ensuring consistent engagement across all compatible transmissions.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4642101109 | TRANSMISSION HOUSING | Encloses the gear train and supports the parking brake assembly |
| 4642301205 | TRANSMISSION HOUSING | Secondary housing for torque converter and clutch packs |
| 0730365125 | TYPE PLATE | Identifies transmission model and service specifications |
| 0631311009 | GROOVED STUD | Secures actuator components and prevents rotational slippage |
| 4642301168 | SCREEN SHEET | Filters debris from hydraulic fluid entering the brake circuit |
| 4642301169 | SCREEN SHEET | Secondary filtration for high-pressure oil passages |
| 0636100621 | HEXAGON SCREW | Fastens the parking brake cover to the housing |
| 4642301186 | SCREEN SHEET | Fine mesh screen for the brake release port |
| 4644106324 | SHIFT SYSTEM | Controls hydraulic engagement of the parking brake piston |
| 4644306598 | PLATE | Guides the actuator rod and distributes clamping force |
