Vacuum Leak/Pump

Well the old girl got cranky on the way home from a short trip today! Cruise worked on the way to, did not engage as I started home, brakes worked fine the only stop until hitting the highway though.

Got close to home and the brakes were pure manual, no assist at all. Had to use the kill switch to shut her down. Could not find any lines off or broken. And several hours later the doors still lock and unlock. Have I lost my vacuum pump?? Or do any of you have some other suggestions for things to check. If it is the pump is it located on the front of the engine?? It is a 1986 300SDL.

Would certainly appreciate any suggestions or help with this little problem. Thanks in advance.

Ric

Did you just change your oil by chance? I just had vacuum trouble on my 84 300D when I inadvertently tugged on one of the lines that go through the firewall. I hunted forever til I realized I could've caused it and checked thru firewall tubing and sure enoughm there it was.... I was back in business in no time!!

Hope this helps.

No fresh oil change. It had been running very well.

[MBenzNL]

The central doorlock runs on an electrical system (additional vacuum pump), so that has nothing to do with the engine's vacuum.
Start checking the engine's vacuum pump while the engine is running. Check whether it does function at all at one of the smaller vacuum lines or the line going to the brake assist.
The vacuum pump is situated on the front of the engine, driver side, above the AC compressor, below the power steering tank and has a rather thick vacuum line going to the brake assist...

greetingz,

Thanks MBenz, that is what I have done, no vacuum from what I can tell when disconnecting a smaller line of the large one going to the brake booster. Was not sure that was the pump though, strange new rattle coming from that area.

[MBenzNL]

Originally posted by R Opp
strange new rattle coming from that area.

No time to waste! Get it replaced and check whether you get out all the parts. You probably have something broken in the vacuum pump and this may cause the complete engine to retire as soon as you get a broken steel part in between of any cogwheel and timing chain! Vacuum pumps do brake down occasionally and I wouldn’t drive a car that already has a rattle coming from the vacuum pump.

greetingz,