S9700515110 - Genuine Wabco Cylinder, Clutch Servo - 1 - wisentpartscenter.com

Description

Genuine WABCO 3866377C91 Clutch Servo Cylinder is part of the manual-transmission clutch control system and reduces the amount of pedal effort needed to operate the clutch. It combines the driver's hydraulic clutch input with pneumatic assistance, making clutch engagement easier and more consistent in heavy-duty truck service.

Key Functions

- Assists clutch release so the driver does not have to provide the full operating force through the pedal.
- Transfers clutch pedal input to the clutch release mechanism.
- Uses hydraulic clutch fluid together with pneumatic pressure to provide servo assistance.
- Helps maintain smooth, predictable clutch operation during frequent shifting.

Fitment & Specifications

- WABCO Material Number: 9700515110
- Length: 267 mm / 10.51 in
- Stroke: 25 mm / 0.98 in
- Maximum Operating Pressure: 10 bar / 145 psi
- Mounting: 4 × Ø 9 mm
- Mounting Hole Spacing: 130 mm / 5.12 in
- Operating Temperature: -30°C to +100°C
- Weight: 4 lb

Verify fitment with us before ordering to ensure the correct part for your application.

Purpose of the Part

The 3866377C91 makes a heavy-duty manual clutch easier to operate by adding pneumatic assistance to the hydraulic clutch command from the pedal. When it is working correctly, the driver gets the clutch travel needed for clean disengagement without excessive pedal effort.

Issue Symptoms / When to Replace

A failing clutch servo can show up as a clutch pedal that suddenly becomes much heavier than normal, incomplete clutch release, difficult gear engagement, or inconsistent clutch operation. Air leakage around the servo or hydraulic fluid leakage can also point to a problem with the unit. Because master-cylinder, linkage, clutch, and air-supply problems can create similar symptoms, those should be checked before replacing the servo.

Brand Information

WABCO has specialized in commercial-vehicle braking, transmission-control, and chassis systems and is now part of ZF's Commercial Vehicle Solutions business. ZF states that its clutch-control operation has more than 40 years of experience developing transmission actuation systems, including master cylinders, servo masters, slave cylinders, and clutch servos for commercial vehicles.

Installation Notes

Use the vehicle manufacturer's installation procedure and the specified SAE J1703 clutch fluid; WABCO does not publish a universal adjustment procedure for every vehicle application.

How to Identify an OEM Part

A genuine 3866377C91 can be identified by the factory WABCO metal tag on the clutch servo. The tag should show the WABCO logo and WABCO material number 970 051 511 0.

Why Buy 3866377C91 from Wisent Parts

  • ⏱️
    Fast shipping
    Orders before 12PM EST ship same business day.
  • 🛡️
    180-day warranty
    All parts covered from delivery date.
  • ↩️
    Easy returns
    30-day returns.
  • ✅
    Verify fitment
    Send VIN/ESN and we’ll confirm.

Shop with confidence

Warranty & Return Information
Warranty Information

Wisent Parts offers a 180-day warranty on all parts from the date of delivery. This warranty covers orders placed directly through our website. If a part fails during this period, we’re here to help - whether it’s a replacement, repair, or refund. For full details, refer to the Warranty page.

Return Information

Wisent Parts accepts returns within 30 days of delivery. All returns are subject to a restocking fee. To qualify, parts must be unused and in their original condition. For full return instructions and restocking fee details, please refer to the Returns page.