🚗 Classic Fault — Mercedes-Benz (1968–1976)
W114 brake master cylinder seal failure
💰 Estimated Repair Cost
$80 – $220 USD
Parts and labour estimate
🔧 Tools Required
Flare nut spanners, bench bleeding kit, brake fluid
📋 Overview
Internal rubber seals in the brake master cylinder deteriorate, causing the master cylinder to bypass internally and reducing braking effectiveness.
🩺 Symptoms
Spongy brake pedal sinking slowly to floor. Reduced braking force. Fluid level dropping without external leaks.
🔍 Possible Causes
Aged rubber seals. Corrosion inside cylinder bore. Overheated fluid.
🛠️ Diagnosis Steps
Press and hold brake pedal for 30 seconds. If pedal sinks, master cylinder is bypassing internally.
✅ Most Confirmed Fix
Replace brake master cylinder. Bench bleed before fitting. Bleed complete brake system.
88% of users confirm this fix worked (19 reports)
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