Overview
The ZF 4651.109.408 PARKING BRAKE is a critical mechanical locking mechanism designed specifically for the WG 100 Series transmission family. This OEM genuine part engages directly within the output shaft assembly to secure the vehicle in a stationary position when the parking brake is applied. By physically locking the driveline, it prevents unintended vehicle movement on inclines or during loading operations. The SKU 4651.109.408 is engineered to ZF’s original tolerances, ensuring precise engagement and disengagement without binding. This component interfaces directly with the 4651101007: TRANSMISSION HOUSING and the 4651301029: HOUSING to form a sealed, robust parking brake system.
Symptoms of Failure
- Intermittent parking brake release failure: The lever or actuator feels stiff or requires excessive force to disengage, often caused by internal corrosion or worn return springs within the 4651.109.408 assembly.
- Vehicle rolls on slight grades when parking brake is set: A clear sign that the internal locking pawl or cone is worn, reducing clamping force. This is a common long-tail search query for “ZF WG100 parking brake not holding.”
- Grinding or clicking noise during engagement: Metal-on-metal sounds indicate that the brake pads or friction surfaces have worn beyond specification, potentially damaging the 0634303928: O-RING seal if debris enters the hydraulic circuit.
- Oil seepage around the parking brake actuator shaft: Worn seals allow transmission fluid to escape, leading to low fluid levels and eventual gear slipping if not addressed promptly.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4651.109.408 |
| OEM Reference | ZF 4651.109.408 |
| Material | Hardened steel with corrosion-resistant coating |
| Weight | 2.4 kg (5.3 lbs) |
| Overall Length | 185 mm |
| Actuator Diameter | 42 mm |
| Seal Type | Integrated O-ring groove (compatible with 0634303928: O-RING) |
| Operating Temperature Range | -40°C to +120°C |
Compatibility
This parking brake is primarily designed for the ZF WG 100 Series transmissions. Based on its mechanical interface and actuator design, it is also compatible with the following ZF models: WG180, WG200, and WG210. It is not suitable for WG 300 or higher series without adapter kits. The 4651.109.408 assembly mounts directly to the 4651301024: HOUSING and requires proper alignment with the output shaft splines. For vehicles using the WG100 in off-highway or construction equipment, this part is a direct replacement for original equipment.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4651101007 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4651301029 | HOUSING | Rear housing supporting output shaft |
| 0634303928 | O-RING | Seals parking brake actuator bore |
| 4651301024 | HOUSING | Intermediate housing for brake assembly |
| 4651203002 | SCREEN SHEET | Filters debris from hydraulic fluid |
| 4651303005 | SCREEN SHEET | Secondary filtration for valve body |
| 0636101032 | CAP SCREW | Fastens housing sections together |
| 0630361028 | SEALING CAP | Protects hydraulic ports from contamination |
| 4475280060 | SCREW PLUG | Seals pressure test ports |
| 0634303312 | O-RING | Seals screw plug and cap interfaces |
