Catalog

MERCEDES-BENZ A9062900212 CYLINDER ASSY CLUTCH

MERCEDES-BENZ A9062900212 CYLINDER ASSY CLUTCH

Product Specifications

Product quality
OEM Equivalent Grade
starstarstar
Wholesale price USD $7.6
Wholesale price CNY ¥51.6
bolt MOQ (Minimal order)
20 pcs
local_shipping Production time
20-50 days
package_2 Shipping Weight: —
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MERCEDES-BENZ A9062900212
MERCEDES-BENZ A6392900012
MERCEDES-BENZ 9062900212
MERCEDES-BENZ 2E0721401C
Overview & Operating Principle
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The CYLINDER ASSY CLUTCH is the clutch master cylinder — the hydraulic pressure-generating component of the hydraulic clutch actuation system that converts the mechanical force applied at the clutch pedal into hydraulic pressure that is transmitted through the clutch fluid line to the clutch slave cylinder or concentric slave cylinder (CSC) at the bellhousing, which in turn actuates the release bearing and diaphragm spring to disengage the clutch. The master cylinder assembly consists of a bore-machined aluminium or cast iron body, a primary cup seal and secondary cup seal on the spring-loaded piston that trap and displace the clutch fluid column when the pedal is pressed, a return spring that retracts the piston when the pedal is released, a reservoir either integral to or remote from the cylinder body that supplies replenishment fluid through a compensating port as the clutch disc wears and the slave cylinder piston travels further forward, and a push-rod that connects the piston to the clutch pedal clevis or pivot. When the clutch pedal is depressed, the piston advances past the compensating port, sealing the hydraulic circuit and generating pressure that is transmitted at equal intensity through the fluid line to the slave cylinder regardless of the pipe routing geometry — the fundamental hydraulic advantage that allows the clutch actuation force to be precisely calibrated by the master and slave cylinder bore diameter ratio independently of the cable routing and mechanical linkage constraints.

This unit — MERCEDES-BENZ A9062900212 — is manufactured to OEM-equivalent specifications: cylinder bore diameter, piston cup seal material and dimensions, reservoir port and compensating port geometry, push-rod clevis attachment or pivot geometry, fluid outlet port thread size and position, overall cylinder body length, and mounting flange bolt pattern for firewall attachment are matched to the original part. Supplied as a complete assembly with reservoir and seals where applicable. Available wholesale from 7.6 USD, MOQ 20 pcs, production lead time 20-50 days.

Clutch master cylinders fail through primary cup seal wear and swelling from fluid degradation — the seal material loses its ability to maintain hydraulic pressure against the compensating port as the piston returns, causing the clutch to creep back toward engagement during sustained pedal depression (pedal sinking); through bore corrosion from water-contaminated fluid that pits the bore wall and prevents the cup seal from sweeping cleanly; and through bypass failure where worn cup lips allow fluid to bypass the piston under pressure, producing a pedal that sinks to the floor. Unlike brake system failures which are immediately safety-critical, a failing clutch master cylinder progresses gradually — the driver typically notices the pedal sinking further over several weeks before the clutch can no longer be fully disengaged.

Symptoms & Diagnostics
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Clutch pedal that sinks progressively toward the floor when held depressed — held at a traffic light the pedal slowly descends and the clutch re-engages — the primary cup seal is bypassing fluid past the piston under sustained pressure; the slave cylinder piston retreats as pressure drops, allowing the diaphragm spring to push the release bearing back and re-engage the clutch; this symptom is the most characteristic presentation of master cylinder internal seal failure.
Clutch pedal that sits lower than previously at rest and requires more travel before the clutch disengages — the engagement point has migrated toward the floor — the compensating port return function has failed; the system is not replenishing fluid correctly, and the effective hydraulic travel is being reduced by air or insufficient fluid in the circuit; check fluid level first — a low reservoir can produce the same symptom from air ingestion — before condemning the master cylinder.
Clutch fluid leak visible at the master cylinder body — wet staining on the firewall below the master cylinder mounting flange or inside the footwell carpet beneath the clutch pedal — the secondary seal or the body-to-reservoir joint has failed; external leakage from the master cylinder causes visible fluid loss and eventual complete loss of clutch hydraulic pressure; the carpet and insulation absorb clutch fluid, producing a distinct sweet chemical smell in the footwell.
Spongy or soft clutch pedal feel — the pedal requires more travel than usual to disengage the clutch and the engagement point is imprecise — air has entered the hydraulic circuit from a failing seal that is allowing air ingestion at the compensating port; bleed the system completely and confirm whether the spongy feel returns within a short driving period; a pedal that becomes spongy again after correct bleeding confirms an active leak source at the master cylinder.
Clutch that cannot be fully disengaged — gears grind when changing with the pedal fully pressed — the master cylinder has failed to the point where insufficient pressure is delivered to the slave cylinder to fully retract the release bearing; the clutch disc is only partially released and continues to transmit some torque to the input shaft; this symptom requires the vehicle to be trailered rather than driven as gearchanges are not possible without drivetrain damage.
Reservoir fluid level that drops progressively without any visible external leak — the fluid is disappearing with no puddle under the vehicle — the internal bypass is pumping fluid past a failed primary seal into the compensating port circuit and out through the reservoir overflow or vent; or the fluid is leaking past a failed secondary seal into the footwell behind the firewall where it is absorbed by the insulation without reaching the ground.
Logistics & Customs
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International HS Code
8708.30
EAEU Customs Code (TN VED)
8708 30 910 0
Typical Net Weight
Country of Manufacture
China
Standard MOQ
20 pcs
Production Lead Time
20-50 days
Always verify the exact 8-digit or 10-digit subheading with your customs broker for the destination country, as tariff schedules and duty rates vary by jurisdiction.
Installation Tips
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  1. Flush the complete clutch hydraulic circuit with fresh fluid before fitting the new master cylinder — degraded fluid that has absorbed moisture and accumulated rubber particles from the old failed seals will immediately attack the new master cylinder's cup seal material if it is not removed; connect a drain pipe to the slave cylinder bleed nipple, fill the reservoir with fresh fluid, and pump the old fluid through until clean fluid emerges before installing the new master cylinder.
  2. Inspect the fluid line between the master and slave cylinder for corrosion, damage, and blocked fittings before connecting to the new master cylinder — a corroded line with restricted internal diameter reduces the hydraulic flow rate available at the slave cylinder, producing a hard, unresponsive pedal even with a correctly functioning new master cylinder; a line fitting that is cross-threaded will produce an immediate fluid leak at the master cylinder outlet.
  3. Lubricate the new master cylinder push-rod clevis pin and all pedal pivot points with silicone grease — the pedal mechanism must move freely through its full travel without stiction or binding that would add to the perceived pedal effort; dry pivot pins produce a notchy pedal feel that is incorrectly attributed to the new master cylinder's piston spring rate; use silicone grease only — petroleum-based lubricants on rubber pedal bushes cause them to swell and bind.
  4. Adjust the push-rod length to achieve the correct pedal free play after installation — the pedal must have 2–5 mm of free travel before the push-rod contacts the master cylinder piston; insufficient free play prevents the compensating port from opening when the pedal is released, trapping pressure in the slave cylinder and causing the clutch to partially disengage at rest, dragging the input shaft; excessive free play reduces effective piston travel and increases the pedal distance required to fully disengage the clutch.
  5. Bleed the hydraulic circuit thoroughly after installation using either the two-person pedal pumping method or a pressure bleeder; the circuit must be completely free of air bubbles before the clutch is tested; confirm pedal feel is firm throughout the full travel with no sponginess; perform the pedal hold test — hold the pedal depressed for 30 seconds and confirm it does not sink — to verify the new master cylinder seals are holding pressure correctly before the vehicle is driven.
  6. Install the new CYLINDER ASSY CLUTCH (MERCEDES-BENZ A9062900212), bleed the complete hydraulic circuit, adjust pedal free play to specification, confirm firm pedal feel with no sinking under sustained depression, and road test through a full range of gear changes confirming smooth, complete clutch disengagement at every change before returning the vehicle to service.
Tools: pressure bleeder or brake bleeding kit, silicone grease for pivot lubrication, push-rod length adjustment tool, torque wrench for master cylinder mounting bolts, fresh clutch fluid (DOT 4 or as OEM specified).
Frequently Asked Questions
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Should the clutch slave cylinder be replaced simultaneously with the master cylinder?
Replacing both master and slave cylinders simultaneously is strongly recommended whenever either cylinder has failed. Both cylinders contain cup seals made from the same rubber compound exposed to the same fluid chemistry and temperature cycling for identical mileage — if one set of seals has failed, the other is at the same degradation stage. Additionally, flushing and bleeding the complete circuit is required when either cylinder is replaced; completing both in the same operation saves a repeat bleed at the additional labour cost of a slave cylinder replacement within a short interval. On concentric slave cylinder (CSC) applications where the slave cylinder is inside the bellhousing and requires transmission removal to access, replacing both cylinders during the same clutch service operation is particularly important as the CSC access cost significantly exceeds the component cost. ok.parts supplies master cylinders and slave cylinders individually and in paired sets at wholesale MOQ from 7.6 USD per unit.
What type of clutch fluid is correct and can DOT 4 brake fluid be used in the clutch system?
Most hydraulic clutch systems share the same fluid specification as the brake system — typically DOT 4 glycol-ether fluid, which is fully compatible with the rubber seals in both master and slave cylinders. Many vehicles use a common reservoir for both brake and clutch master cylinders, making the same fluid mandatory. However, some manufacturers — particularly certain Asian vehicle brands — specify a specific hydraulic clutch fluid that may be mineral oil-based rather than glycol-based; mineral oil-based fluid is incompatible with DOT 3/4 system seals and will rapidly destroy them. Always confirm the fluid specification from the reservoir cap marking or the vehicle handbook before filling — mixing an incompatible fluid causes immediate seal swelling and system failure.
How does the OEM-equivalent aftermarket unit compare to the genuine OEM part?
OEM-equivalent units in this catalogue replicate the current OEM design geometry and material specification. Quality is verified against OEM cross-reference data. When ordering in bulk, confirm with our team that the specification matches the latest OEM revision for your application.
Is white-label or custom packaging available for wholesale orders?
Yes. ok.parts works directly with the manufacturing facility and can accommodate neutral white-label packaging or fully branded packaging with your company logo, part numbers, and barcode. Minimum order quantities and lead times for custom packaging may differ from standard stock. Contact the team via the inquiry form to discuss your specific requirements.
Frequently Replaced Together
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PartReason for Combined Replacement
Clutch Slave Cylinder
External or concentric (CSC) — OEM ref. varies		The slave cylinder cup seals share the same fluid chemistry exposure and service life as the master cylinder — if the master has failed from seal degradation, the slave is at the same wear stage. Replacing both simultaneously eliminates a repeat hydraulic circuit bleed and slave cylinder replacement within a short interval, and ensures the complete hydraulic actuation system is renewed with matched new components operating on fresh fluid.
Clutch Fluid
DOT 4 or OEM-specified hydraulic fluid		Clutch fluid absorbs moisture from the atmosphere through the reservoir vent and the hydraulic lines, progressively lowering its wet boiling point and accelerating rubber seal degradation. A master cylinder that has failed from seal swelling has been operating in degraded fluid that contributed to the seal's accelerated deterioration. Replacing the fluid simultaneously with the master cylinder eliminates the degraded fluid as a recurring attack on the new cylinder's seals.
Clutch Pedal Push-Rod and Clevis Pin
OEM ref. varies — where separately replaceable		The push-rod and clevis pin at the pedal-to-master-cylinder connection accumulate wear at the clevis hole and pin diameter from the high cycle count of clutch pedal use. A worn clevis pin allows free play between the pedal and the master cylinder piston that reduces the effective piston travel, requiring the pedal to be pressed further before the clutch begins to disengage. Inspect the clevis pin diameter and clevis hole for wear when the master cylinder is removed and replace if any freeplay is detectable.