Timing chain replacement: 166961/91 in W414 - chain — MERCEDES-BENZ
Timing chain replacement — 166961/91 in W414 - chain on Mercedes-Benz: 105 steps, engines 166.961, 166.991.
Workshop procedure for MERCEDES-BENZ — the exact step sequence and torque figures, straight from real workshop data.
📋 Procedure
Preparation and removal
- Always renew the timing chain
- Release the chain
- Secure the chain
- Remove the brake servo vacuum line
- Disconnect the vacuum hose from the inlet manifold
- Disconnect the idle speed control connector
- Disconnect the fuel injector wiring
- Disconnect the fuel line
- Tighten the special tool
- Disconnect the crankcase breather hose
- Remove the special tools
- Disconnect the camshaft position sensor electrical connector
- Remove the windscreen washer fluid container
- Remove the air pump switch-over valve
- Remove the cylinder head cover
- Remove the ignition coil cover
- Note: Do not tighten the bolts
- Refit the bolts
- Remove the expansion tank
- Remove the chain tensioner
- Secure the chain
- Use the special tools to remove the timing chain pins
- Remove the special tools
Installation and checks
- Timing chain assembly links:
- Connect the old chain to the new one
- Stage 1:
- Installation sequence:
- Fit the chain tensioner
- Refit the spark plugs
- Refit the ignition coil with bracket
- Refit the ignition coil cover
- Check the timing marks
- Refit the cylinder head cover
- Refit the air pump switch-over valve
- Reconnect the camshaft position sensor electrical connector
- Renew the seals
- Refit the crankcase breather hose
- Reconnect the fuel line
- Reconnect the fuel injector wiring
- Reconnect the idle speed control connector
- Reconnect the vacuum hoses
- Refit the brake servo vacuum hose
- Refit the engine control unit
- Refit the inlet manifold support
- Refit the dipstick tube
- Refit the air filter
- Reconnect the battery earth cable
Other MERCEDES-BENZ procedures
Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.
Seen a figure that does not match your manual? Write to us — we correct it and note when. support@torqfix.com
The story behind TorqFix →Workshop data on this page last updated 20 Sep 2026.