2006-2012 Mitsubishi Eclipse Clutch Master Cylinder: Failure Symptoms & Replacement Guide
Diagnose a spongy or sinking clutch pedal and learn how to choose the right master cylinder for your 4-cylinder GS or V6 GT Eclipse.
- The clutch master cylinder for the 4-cylinder (GS) and V6 (GT) models are likely different; always verify the part is correct for your engine.
- A spongy pedal that sinks to the floor and difficulty shifting are the most common signs of failure.
- The hydraulic system MUST be properly bled of all air after replacement, or the clutch will not function.
- A recall exists for the BRAKE master cylinder on some 2006 models, which is a separate part and should not be confused with the clutch master cylinder.
Symptoms of a Failing Clutch Master Cylinder
A failing clutch master cylinder will give several clear warning signs. Ignoring them can leave you stranded, as a complete failure will make it impossible to shift gears. Look for the following symptoms:
- Spongy or Sinking Clutch Pedal: This is the most common symptom. The pedal may feel unusually soft, mushy, or sink to the floor with little resistance. This is often caused by air in the hydraulic lines from a leak or by failing internal seals.
- Pedal Sticks to the Floor: After you press the clutch pedal, it may not return to its normal position. This indicates a severe loss of hydraulic pressure or a mechanical failure within the cylinder.
- Difficulty Shifting Gears: You may find it hard to get the transmission into gear, especially first and reverse. You might also hear grinding sounds when trying to shift. This happens because the failing cylinder can't generate enough pressure to fully disengage the clutch.
- Low or Contaminated Clutch Fluid: Check the small plastic reservoir connected to the master cylinder. If the fluid level is low, you have a leak in the system. If the fluid, which should be nearly clear, is dark or black, it means the rubber seals inside the cylinder are breaking down and contaminating the fluid.
- Visible Fluid Leaks: You may see brake fluid leaking from the cylinder onto the firewall, either in the engine bay or inside the car under the dashboard behind the clutch pedal.
Compatibility Warning: The 4-cylinder (GS) and V6 (GT) models of the 4th generation Eclipse often use different clutch master cylinders. While some aftermarket parts claim broad compatibility, OEM part numbers differ. Always verify the part you are buying is correct for your specific engine and transmission (5-speed vs. 6-speed) to avoid installation problems.
Known Issues, Recalls, and Technical Service Bulletins (TSBs)
While there are no widespread, specific recalls for the clutch master cylinder on the 2006-2012 Mitsubishi Eclipse, there are related items to be aware of:
- Brake Master Cylinder Recall (2006 Models): Early production 2006 Eclipse models were subject to NHTSA Recall #05V247000 for a defective brake master cylinder. An internal seal may have been installed incorrectly, leading to a spongy brake pedal and increased stopping distance. This is a separate part from the clutch master cylinder, but the similar name can cause confusion.
- General Manual Transmission Complaints: Owners have reported general issues with the manual transmissions in these models, including difficulty shifting and clutch-related rattles, which may or may not be related to the master cylinder itself. These symptoms can also be caused by a worn clutch disc, pressure plate, or slave cylinder.
Buying a Used Clutch Master Cylinder: What to Check
A used OEM clutch master cylinder can be a reliable and cost-effective alternative to expensive new parts or lower-quality aftermarket units. Here’s what to inspect before buying:
- Check for Leaks: Thoroughly inspect the entire unit for any signs of fluid residue, especially around the piston boot (the rubber cover where the pushrod comes out) and where the fluid line connects. A clean, dry unit is essential.
- Inspect the Reservoir: Check the plastic fluid reservoir for any cracks, especially around the base where it connects to the cylinder body. The plastic can become brittle with age. Ensure the cap and its seal are present and in good condition.
- Examine the Body: Look for any significant corrosion on the aluminum or metal body of the cylinder. While surface discoloration is normal, deep pitting or corrosion can indicate a part that has been exposed to harsh conditions.
- Verify Part Numbers: If possible, match the part number on the used unit to your original part or the known OEM numbers for your vehicle's engine (2.4L or 3.8L). Known OEM numbers include 2345A020, which replaces 2345A004.
- Pushrod Condition: Ensure the pushrod is straight and the clevis (the fork-like end that connects to the pedal) is not damaged or excessively worn.
Pro Tip: For a complete repair, it is highly recommended to replace the clutch slave cylinder at the same time as the master cylinder. Both components wear at a similar rate, and replacing only one can cause the older part to fail shortly after, requiring you to bleed the system all over again.
Cost Comparison
Prices for a clutch master cylinder for a 2006-2012 Eclipse can vary significantly based on the source of the part.
| Part Type | Estimated Cost |
|---|---|
| New OEM | $195 - $220 |
| New Aftermarket | $35 - $145 |
| Used OEM | $50 - $100 |
| Shop Labor | $117 - $172 |
Replacement Overview & Difficulty
Replacing the clutch master cylinder is a moderately difficult job that can be done by a skilled DIY mechanic. The main challenges are accessing the nuts on the firewall behind the dashboard and properly bleeding the system afterward.
- Difficulty Rating: 3 out of 5
- Estimated Time: 1.5 - 2.5 hours
- Process: The job involves removing the driver's side under-dash panels, disconnecting the pushrod from the clutch pedal, removing two nuts holding the cylinder to the firewall, disconnecting the hydraulic line in the engine bay, and then installing the new part in reverse order.
- Bleeding is Mandatory: After installation, the entire clutch hydraulic system must be bled to remove all air. This typically requires two people: one to pump the clutch pedal and another to open and close the bleeder valve on the slave cylinder. Failure to bleed the system properly will result in a spongy pedal and a non-functional clutch.
Frequently Asked Questions (FAQ)
Can I drive with a failing clutch master cylinder?
No. It is not safe to drive with a failing clutch master cylinder. The symptoms progress quickly, and a complete failure will leave you unable to disengage the clutch, meaning you cannot shift gears or may stall unexpectedly in traffic. If your clutch pedal feels spongy or is sticking, you should have the vehicle towed for repair.
Is the clutch master cylinder the same for the 4-cylinder GS and V6 GT Eclipse?
They are generally considered different parts. While some aftermarket manufacturers may list a single part for both, OEM catalogs and most parts stores show separate listings for the 2.4L 4-cylinder and 3.8L V6 models. Always confirm compatibility with your specific engine before purchasing.
What kind of fluid does the Eclipse clutch system use?
The clutch system uses standard DOT 3 or DOT 4 brake fluid, the same fluid used in your brake system. Always use fresh fluid from a sealed container when filling or bleeding the system, as brake fluid absorbs moisture from the air, which can reduce its effectiveness and cause corrosion.
Do I need any special tools to replace the clutch master cylinder?
No highly specialized tools are required, but you will need a good set of metric wrenches (including a flare nut wrench for the hydraulic line to prevent stripping), sockets, and potentially some universal joints or extensions to reach the nuts behind the dashboard. You will also need a container and a small hose for the bleeding process.
Technical Specifications
OEM Part Numbers: 2345A004 2345A013 2345A019 2345A020 MN184179 MR980563
Uses DOT 3 or DOT 4 brake fluid. Bore size is approximately 17mm or 0.688 inches for some aftermarket versions.
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Mitsubishi Eclipse: