PeachParts Mercedes-Benz Forum - View Single Post - Trying to track down those pesky leaks...

MikeTangas · #6 12-19-2002, 01:34 AM

First off you really should get a mighty-vac, really helps when troubleshooting the system.

When you say none unlock, do you mean with the key, or when you manually lift the driver's lock knob from inside? If it is with the key only, that might not be a vacuum related problem. There is a small kidney shaped piece in the lock mechanism that likes to break, unfortunately that piece cannot be obtained separately (at least that I couldn't get one). I did find that there is also a small set/adjustment screw which moves the business end of the mechanism a little closer to the lockworks, adjusting this screw allowed the parts to mesh and the lock functioned normally again.

If none unlock when lifting the knob, then we're on vacuum related ground. Using your newly purchased mighty-vac, you can check function at the master valve in the driver's door. The yellow line is the main vac feed, the other two are for lock and unlock (can't remember which color is which right now). Test them both. If none unlock from this point, then you have a major vacuum leak and you'll have to track it down.

Remember, vacuum leaks do cause poor running conditions, and having a leak in this system will cause lower than optimal manifold vacuum (that;s where the vac is drawn from). Don't forget to check out the check valve in the main line between the manifold and first split. those often go bad and you'll hold no vacuum at all.