W126 central locking slow on one door — vacuum leak hunt tips?
The driver’s door locks instantly but the rears take a couple of seconds and sometimes give up. Where do I start with the vacuum system on these?
1 answer
September 6, 2026
★ Best answer
Classic W126 symptom. The system runs off a pump in the trunk — slow doors usually mean a leaking actuator or a cracked line on that door's run, and one bad actuator drags the whole system down. Pull the door card on the slowest door first and test the actuator with hand vacuum; lines perish where they pass through the door jamb.
Log in or create an account to answer.
Got a different question?
Ask the community →