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View Full Version : 300D locks don't lock all the time

08-23-2005, 03:03 AM
I am new and have only read a little on this message board. I think that I may have the same vacuum problem as mentioned before:

My automatic locks work intermittently. Sometimes they all lock/unlock, sometimes differnet ones do. Tonight they did not lock at all. As a side note, and perhaps not entirely relevant, I have noticed that the engine takes a while to shut off (sometimes) after turning the key to off. Any suggestions?
Thanks in advance

08-23-2005, 10:14 PM
300D Engine will not turn off..... (14 views)

Message: the presence of black motor oil in the vacuum hose's

see if the vacuum hose to the back of the injection pump has fallen off because the oil has swollen the rubber hose.

oil comes from a torn vacuum pump diaphram at the very front of the motor - and oil works its way into the vacuum hose system , reaching the vacuum switch mounted on the ignition/steering lock inside the dashboard. This motor oil will eat the control switch internal seals, pump shut-off diaphram on back of the injection pump. Anywhere the oil has reached - must be replaced.

if your not mechanically inclined - make a date with an M-B dealer for diaphram replacement, and system cleaning and replacement of all the effected hoses.

in the mean time I guess you found the red tag on the engine linkage
lever saying "STOP" when pushed to shut off the fuel supply.

Very common repair.

08-23-2005, 10:16 PM
Chasing a vacuum leak = very common (216 views)

Message: EARLY STAGE OF MOTOR OIL entering the vacuum system and it will ruin the vac switch mounted at the steering /ignition lock . Remove the lower dash panel, disconnect the speedo cable from behind, carefully fush out the instrument cluster, unscrew the hard oil pressure hose to it's gauge, do not gouge the dash padding with the light reostat while doing all this. NOW you can remove the two vac hoses to the key vacuum switch and inspect for the presence of oil dripping out of the hoses, and if oil is there - replace the vacuum switch and the rubber hoses, and start cleaning back to the source of the oil - the motor.
The oil isually comes from a leaking Vacuum Pump Diaphram at the front of the motor. Oil will be present also in the brake booster hose and all the other vacuum hoses in the motor room. Any rubber hose with the oil in it must be replaced, and the hard plactic hoses flushed clean with a degreasing spray cleaner like Brakekleen. Where ever oil got to, those vacuum swirches need to be replaced also. The diesel motor oil eats them inside. Of course replacing the vacuum pump diaphram is another job to do. Oil doesn't make it to the doors, so they are not a worry. They will resume operation when all the other stuff is addressed.

installing a small see through inline gas filter at the brake booster T fitting will give you future early warning of the presence of oil , and prevent oil traveling further into all the branches of hoses just at that booster hose T supply fitting. This was a M-B Service Bulletin ages ago

08-31-2005, 02:09 AM
How much are all the parts cost?

09-01-2005, 08:20 AM

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