Overview
This OEM genuine ZF 4657.330.028 DIAPHRAGM is a critical pneumatic actuation component designed specifically for the WG 190 and WG 210 series transmissions. Positioned within the clutch housing assembly, this diaphragm converts air pressure into mechanical force to engage and disengage the clutch pack. The SKU 4657.330.028 ensures a precise factory seal and response time, directly influencing shift quality and torque transmission. When paired with a robust TRANSMISSION HOUSING, this part maintains the integrity of the entire clutch actuation circuit.
Symptoms of Failure
- Air leaks during clutch engagement: A worn 4657.330.028 diaphragm often causes audible hissing or a gradual loss of air pressure, leading to soft or incomplete gear engagement.
- Erratic or delayed shifting: When the diaphragm fails to hold pressure, operators experience hesitation between gear changes, particularly under load.
- Oil contamination in the air system: A ruptured diaphragm can allow transmission fluid to migrate into the pneumatic lines, causing sludge buildup and valve sticking.
- Reduced clutch holding torque: A cracked or stretched diaphragm cannot generate sufficient force, resulting in clutch slip during acceleration or hill climbs.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4657.330.028 |
| Material | Nitrile rubber (NBR) with fabric reinforcement |
| Outer Diameter | 210 mm (estimated) |
| Inner Diameter | 28 mm (estimated) |
| Thickness | 4.5 mm (estimated) |
| Operating Pressure | 6–10 bar |
| Weight | 0.35 kg (estimated) |
| OEM Reference | ZF 4657.330.028 |
Compatibility
This diaphragm is engineered for the ZF WG190 and WG210 series transmissions. It also fits select variants of the WG180 and WG200 models where the pneumatic clutch actuator shares the same mounting pattern. Always verify the condition of the HOUS.FRONT SECT and the HOUSING REAR PART when replacing the diaphragm, as misalignment can accelerate wear. The assembly also relies on a CYLINDRICAL PIN for precise alignment during installation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4657101031 | TRANSMISSION HOUSING | Main structural casing for gear and clutch assembly |
| 4657201027 | HOUS.FRONT SECT | Front section housing the input shaft and clutch |
| 4657201020 | HOUSING REAR PART | Rear section supporting output shaft and bearings |
| 0631306792 | CYLINDRICAL PIN | Alignment dowel for housing mating surfaces |
| 0636100801 | CAP SCREW | Fastener for securing housing sections |
| 4656301148 | FIXING PLATE | Retainer for clutch piston and diaphragm |
| 4657301032 | SCREEN SHEET | Filter screen for oil return line |
| 4657301033 | SCREEN SHEET | Secondary filter screen for pressure line |
| 0636100803 | CAP SCREW | Bolt for diaphragm cover plate |
| 4681301040 | OIL FEED.HOUSG. | Lubrication supply housing for clutch pack |
Frequently Asked Questions
Q: How do I know if the 4657.330.028 diaphragm is the correct replacement for my WG210?
A: Verify the part number stamped on your existing diaphragm. The 4657.330.028 is the OEM standard for WG190 and WG210 models. If your unit uses a different actuator style, cross-reference the outer diameter and bolt pattern.
Q: Can I reuse the old fixing plate or cap screws when installing this diaphragm?
A: ZF recommends replacing the FIXING PLATE and CAP SCREW with new ones to ensure proper clamping force and prevent air leaks.
Q: What causes premature diaphragm failure in these transmissions?
A: Contaminated air supply (moisture or debris) and misalignment of the HOUS.FRONT SECT are the most common causes. Always inspect the CYLINDRICAL PIN for wear during service.
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Email: info@partszf.com |
Phone: +86 158 2286 3467 |
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