My W124 was built in 04/90 and so has the first version central locking. The rear locks will not lock by either of the front door keys but can be manually locked. The fuel door and trunk lock fine. The vacuum pump runs for what seems like quite a long time but eventually shuts off. On opening the car, all door locks function normally if maybe a bit more slowly than before.

In starting to trace vacuum lines at the LR door, it looks like the vacuum line has been replaced because what's there is a 3/8 OD rubber hose while the lines at the pump are 5mm OD of a hard yellow plastic. Then the line disappears into the door post and I have no idea where it goes.

Would appreciate your thoughts. If I have to trace vacuum lines how does one get at them? Do I have to remove the seats, rugs, various trim? Can I get at the lines from underneath?

If I delay doing this or ignore it will the pump suck up trash and fail?

Thanks a lot.

John