is my shade tree mechanic right? vacuum seal
 

1984 300cd turbo 241K miles. brakes got very hard then engine began NOT shutting off. my local mechanic says the vacuum seal in the engine is bad - may need a new engine. is this correct? have decided with great sadness in my heart to sell this beloved, rockin' car :(. have put the craigslist post here on another thread. I need to know how to honestly answer the questions I am getting. please help.

no you do not need a new motor. Check the output of the vacuum pump it should be a bout 20-25" at idle.

Those were exactly the symptoms I had when my vacuum pump needed to be replaced.

Never return to that "mechanic". He either knows nothing at all or is trying to steal your money.

You could sell your car to me for $1500 :D. Kidding aside though, you definitley don't need a new engine. It sounds like it's just the vacuum pump which if you are inclined you can rebuild for about $50. Check the link below for the part. Before anything though, get yourself a mityvac and check the output on the pump (as 79mercy mentioned) to determine if thats really the cause .

http://www.**********.com/search/product.aspx?sid=bs0o1u45tzyony45s2prsc45&makeid=800016@Mercedes&modelid=1193576@300CDT&year=1984&ci d=18@Electrical%20%26%20Vacuum&gid=5025@Vacuum%20Pump%20Repair%20Kit

That has to be a front runner in the Most Bizarre Diagnosis Contest.

You don't need a new engine; you need a new mechanic!!!

May not even be a pump. It could be a broken hose or the check valve.

Definitely, don't return to that mechanic. In fact, it may be something as simple a cracked rubber flex fitting. To replace a majority of the flexible rubber portions of your vacuum system is ~$10-$15.

this guy is a clown, you dont have a blown engine.

It probably is due to a hose being disconnected some where. As others suggested put a guage on the vac. line near the vac pump and test it making sure to test ahead of all other points where lines come off the main vac hose.
You could also just start tracing the vac line to see if there are any open connections.

Hi

DieselGiant.com has a nice DIY vacuum system troubleshooting pictorial on its maintainence section. Vacuum problems are usually an easy fix.

Joseph

If it is the pump, shut off the engine right away before bits get pulled into the chain rails and you have a very expensive catastrophic event. Replace the pump and do not restart the car until you do.

It could be the pump, but it's probably just a vacuum leak somewhere in the system.