SevereAffected: 2012-201770,000–120,000 miles

Ford Fiesta Mk7 1.0 EcoBoost 100bhp — Clutch Slave Cylinder / Concentric Bearing Leak

The concentric slave cylinder (CSC) inside the gearbox bellhousing fails, leaking hydraulic fluid and causing clutch failure.

Severity

Severe

DIY Difficulty

Professional Only

Est. Cost

£400–£800

OBD Codes

None

Component Diagram

Clutch

Typical layout and location for the Clutch assembly.

Reference Illustration

Symptoms

Clutch pedal stays flat to the floor
Difficulty engaging gears, especially 1st and Reverse
Pool of brake fluid under the gearbox bellhousing

Root Cause

The seals inside the concentric slave cylinder wear out. Because it is mounted inside the bellhousing on the gearbox input shaft, the entire gearbox must be removed to replace a £40 part.

How To Fix

Check brake/clutch fluid reservoir level (it will be low).
Gearbox must be removed to access the CSC.
Always replace the entire clutch kit at the same time, as the leaking fluid ruins the friction plate.
Cost: £400-800

Estimated Repair Costs

Repair Option	Est. Cost (GBP)
DIY (parts only)	£160–£320
Independent Garage	£400–£800
Main Dealership	£640–£1280

Other Faults on This Variant

Timing Chain Stretch and Tensioner Failure

Critical

2012-201540,000–100,000 miles£600–£1200

Pre-2016 Ford 1.0 EcoBoost engines suffer from premature timing chain stretch. The plastic tensioner can fail, causing catastrophic engine damage with little warning.

Coolant Loss from Cylinder Head

Severe

2012-201860,000–120,000 miles£500–£900

The 1.0 EcoBoost has an integrated exhaust manifold cast into the cylinder head. This design causes head gasket stress and coolant loss, sometimes causing overheating.

Thermostat Failure and Overheating Risk

Moderate

2012-201850,000–100,000 miles£80–£180

The plastic thermostat housing on the 1.0 EcoBoost is prone to cracking. A stuck-open thermostat causes the engine to run cold and burn more fuel; a stuck-closed thermostat causes rapid overheating.

Disclaimer: Repair cost estimates are indicative and based on community data. Always get a quote from a qualified mechanic before proceeding with any repair.