Installation Method for Mercedes-Benz Clutch Release Bearing (Release Fork Bearing/Thrust Bearing)

Safety and Preparation

1. Park the vehicle on a level surface, engage the parking brake, disconnect the power supply, and shift to neutral. Lift the front of the vehicle with a jack and secure it with safety stands; never rely solely on a jack during operation. Drain and collect the transmission oil.

2. Disconnect the negative battery terminal, clutch oil pipe/hydraulic slave cylinder, clutch pedal linkage/cable, shift linkage, drive shaft/half shaft, starter motor, and flywheel housing bolts. Mark the components clearly and store the bolts in classified manner.

3. Prepare tools: Torque wrench, centering tool, bearing press-fitting fixture, copper hammer, cleaning agent, high-temperature molybdenum-based grease, brake fluid (matching the vehicle model specifications), and sealant.

4. Inspect the new part: The release bearing should rotate smoothly without jamming or abnormal noise, and its seal should be intact. Verify that the part number matches the original one. For pre-lubricated sealed bearings, do not disassemble, clean or refill grease. For non-sealed types, apply grease in accordance with requirements.

Transmission Removal and Old Bearing Dismantling

1. Support the transmission with a dedicated lifting frame or bracket. Loosen the connecting bolts between the flywheel housing and the engine, and remove the transmission smoothly to avoid colliding with the input shaft and pilot bearing.

2. Remove the release fork and dismantle the old release bearing: For circlip-type bearings, remove the circlip with circlip pliers; for bolt/spring-type bearings, disassemble in reverse order. Record the installation direction and clearance of the old bearing as a reference for assembly.

3. Thoroughly clean the release sleeve, input shaft sleeve, release fork, and the contact surfaces of the release fingers to remove oil stains, iron filings, and burrs. If necessary, polish with fine sandpaper and degrease the surfaces.

Installation of New Release Bearing (Core Steps)

1. Directional alignment and press-fitting: Determine the installation direction according to the part markings or the imprints of the old bearing. Press the bearing onto the release sleeve, with pressure applied only to the end face of the mating race, until it abuts against the shaft shoulder firmly. Never strike or transmit force through the rolling elements to prevent damage to the raceways and steel balls.

2. Lubrication: Apply a thin layer of high-temperature molybdenum-based grease to the inner bore of the release sleeve, the outer surface and oil grooves of the input shaft sleeve. Lightly coat the contact points between the release fork and the bearing, as well as the ends of the release fingers, to avoid dry friction and abnormal noise. For pre-lubricated sealed bearings, only lubricate the mating surfaces.

3. Assembly of release fork and bearing unit: Slide the bearing unit onto the input shaft sleeve, install the release fork and ensure it is properly engaged/abutted with the bearing. Install the circlip or spring to ensure reliable locking. Check that the bearing slides smoothly axially and rotates freely circumferentially.

4. Clearance and travel adjustment: For constant-contact type bearings, ensure moderate contact force between the release fingers and the bearing end face. For non-contact type bearings (adopted in most Mercedes-Benz hydraulic clutch systems), control the clearance within 2–3 mm to reserve allowance for friction disc wear, avoiding incomplete disengagement or poor engagement.

Transmission Resetting and Hydraulic/Cable System Handling

1. Centering of clutch assembly: Use a centering tool or the old input shaft to center the driven disc and pressure plate, ensuring the input shaft can be inserted smoothly. Tighten the pressure plate bolts evenly in a diagonal sequence in stages to the specified torque to prevent deformation.

2. Transmission hoisting: Push the transmission slowly into place and align it with the flywheel housing. Tighten the flywheel housing bolts evenly in a diagonal sequence in stages to the specified torque. Reinstall the drive shaft/half shaft, starter motor, shift linkage, etc., and reconnect the negative battery terminal.

3. Hydraulic system handling (for most Mercedes-Benz models): Install the clutch slave cylinder, apply gasket or sealant as required by the vehicle model. Fill with matching brake fluid, bleed air from the slave cylinder bleeder valve until no air bubbles are present in the pipeline and the pedal feels firm. Check for leaks and top up brake fluid to the scale line.

4. Cable-type system (for some old models): Install the clutch cable and adjust the free travel to ensure complete disengagement and smooth return.

5. Fill the transmission oil to the specified level and check for leaks at the oil seals and connection points.

Test Run and Calibration

1. Static inspection: Verify that the clutch pedal free travel complies with the vehicle specifications (usually 10–20 mm), the pedal depresses smoothly without jamming, the clutch disengages completely, and gear shifting is free of impact.

2. Road test: Perform cold start, gear shifting, rapid acceleration/deceleration. Check for abnormal noise, slipping, incomplete disengagement, or engagement jitter. Recheck the pedal travel and leakage after the vehicle warms up.

3. Re-inspection: If abnormal noise occurs, check the clearance, lubrication condition, or installation direction. If gear shifting is difficult, check whether the hydraulic system is fully bled or the free travel is too small. If slipping occurs, check the pressure plate bolt torque, friction disc direction, and wear condition.

Key Prohibitions and Precautions

• Never strike or press-fit the bearing through rolling elements, and never heat the bearing by oil boiling or high-temperature heating, otherwise it will cause premature failure of the bearing.

• Do not disassemble, clean or refill grease for pre-lubricated sealed bearings; use high-temperature molybdenum-based grease for non-sealed types instead of ordinary lithium-based grease.

• The hydraulic system must be fully bled, otherwise the pedal will feel soft and the clutch will disengage incompletely.

• Tighten the pressure plate bolts evenly in a diagonal sequence in stages to the specified torque to prevent deformation and jitter.

• Excessively small release clearance may cause friction disc burnout and release finger wear; excessively large clearance may lead to difficult gear shifting. Adjust the clearance in accordance with the vehicle service manual.

References：

Explanation & Source Tracing

1. Content Sources

   The content integrates general principles from the Mercedes-Benz Original Service Manual (WIS/ASRA), hands-on experience of after-sales technicians, industry-standard installation protocols for clutch and release bearings, as well as common key points applicable to mainstream models (e.g., W204/W212/W164). Meanwhile, model-specific details varying by chassis numbers are omitted to present a universal procedure for quick reference and application.
2. No Publicly Citable Origin

   No text is quoted from third-party websites, forums, or published materials, and there are no corresponding DOIs, links, or ISBNs. If required, I can cross-reference this summary with chapter numbers, torque values, and clearance parameters from the original factory manual, or label it as "Technical Summary Based on Mercedes-Benz Maintenance Specifications" for internal use only.
3. Distinction Between Factory Specifications & Universal Procedures

   The original factory manual provides precise data—including bolt torque values, bleeding steps, and tool part numbers—tailored to specific chassis numbers and transmission models. The content provided here is a universal version designed for preliminary guidance. For accurate operation, it is recommended to consult the WIS system or contact an authorized Mercedes-Benz service center with your vehicle’s specific chassis number.

Supplementary Recommendations

1. Label it as "Technical Summary Based on Mercedes-Benz Maintenance Specifications (Original Compilation)" and append the scope of application (e.g., Suitable for Mercedes-Benz manual/hydraulic clutch models; not applicable to DCT models).

2. Supplement original factory manual chapter numbers, torque values, and clearance parameters based on your vehicle’s chassis number to enhance its authority.

3. Create a Comparison Table of Factory Specifications vs. Universal Procedures for cross-verification.