Symptoms
A pedal that sinks, a clutch that won't fully release, grinding into gear, or fluid on the footwell or firewall. Many trucks also have a clutch booster, so a heavy pedal can mean an air fault rather than a hydraulic one.
The fix, step by step
- Drain or siphon the reservoir.
- Disconnect the pushrod and hydraulic line, unbolt the master cylinder and fit the SBU replacement.
- Bleed the clutch at the slave or booster end until the fluid runs clear and bubble-free, then check the free play and full release with the engine running.
Tools & part numbers
- Flare-nut wrenches
- bleed hose and bottle
- brake fluid to the manual's spec
Where to buy the parts
Clutch master cylinder, SBU (heavy-series) UnimogsExpedition Imports ↗Amazon ↗
Clutch master cylinder reservoirExpedition Imports ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Mercedes-Benz Unimog U1300L (435) parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.