I have an 83 300TD wagon with 240,000 mi, so far runs good, I am currently installing new brakes [all components] when my no shut off problem occoured.

I have been reading all posted info re no shut off and am trying to find cause of problem. There are a group of vac lines passing throught firewall adjacent to brake boster, one of the lines is black and I found it under the dash not connected to anything and can't find anything to conect it to.

Does anyone know what this line is and where it goes

RJ

The black line is not your problem, it is a vent line and is supposed to be open under the dash.

I have a newly acquired 84 300td which will run for several minutes, or even twenty plus minutes before shutting off. I don't mind opening the hood to press the red stop but I think this will become bothersome in the winter, or to my wife when she chooses to drive it.
The vacuum lock system works feebly.The drivers side door key will lock the rear door on that side only if that door is opened most of the way.
Where do I start with this issue.?

Greetings,


Try your fuel shut off valve which is located under your dash toward the steering housing. Small valve that shuts off vacuum to your fuel rack when the key is turned to the off position. Mechanically operated by the key switch.


Charles

__________________
"Tell me and I will listen, Teach me and I will learn, Show me and I will accomplish, Involve me and I will succeed."
'84 300SD 256,000 Gold on Brown (Mileage Award)
'86 300E 246,000 Blue on Tan

Benz50,

First get a Mighty Vac and a vacuum diagram and start checking vacuum points from the vacuum pump back thru the car. Someplace U have a vacuum leak U have to find and repair.

P AE H

perhaps you don't have the check valve installed (or the right way) on the new line? my 1980 240d has had trouble and i finally nailed the problem today in that my cruise control was leaking all the vacuum and the vacuum tank (under the rear window in the trunk) grommet was leaking so badly the tank didn't hold any vacuum, i would recommend sealing that grommet sometime with silicon sealant. as far as your transmission problems go it sounds like too much vacuum is being applied to the transmission which would make it really rough, check to make sure everything is hooked up right especially your check valves.

nicofoxford,

The transmission in m '86 300SDL shifted very rough when there were vacuum lines missing and the transmission had little vcacuum.

P E H

P E H,
What is the first thing your transmission vacuum line connect into? If yours is set up like mine is it should be going into a regulator valve on top of the valve cover that is opened and closed with the accelerator linkage. It should not shift nicely with no vacuum or constant vacuum on the tranny line.

nickofoxford,

The vehicle I was refering to is an '86 SDL (6 cylinder) and the trans vacuum connections is all together different.

I ruined an '80 300SD trans by connecting the lines to the vacuum valve incorrectly. I had full vacuum going to the trans all the time. Soon the trans started to slip and had to be replaced. So be careful how U connect the lines.

I never had a 300SD with the vacuum connections on the valve cover so I know nothing about them.

P E H

I have actually replaced out the shut off valve on mine several years ago. Now I have to pop the hood again, but only once I had to replace the brake master cylindar. It leaked into the brake booster. So of course I replaced the brake booster. As of today I replaced the line going from the brake booster to the vacuum pump. Car still will not shut down on its own. I pulled my instrument panel to check the lines at the ignition. There was oil on them. I think I have to replace the vacuum pump on the ignition, but am not sure how to get the thing off. There is not much room to move around or see anything. I have the new pump. I ordered it along with the hose just in case. Does anyone have any easy instructions to change it out?

Greetings,

Do you have any oil accumulation in the air filter housing at all? If you do then your problem is the vacuum pump under the hood with a leaking seal that is minimal in cost to replace but takes about an hour or so if you do not remove the pump to do the replacement. Your engine shut down is strictly vacuum operated and the valve or switch you see with wires is simply to shut off your accessories. Your engine is solely shut off by starving it of fuel, period. Does the emergency shut-off work under the hood? I'll help you all I can but you need to be specific on what it does or does not do when I ask you.

Charles

A leak of oil on your lines when under the dash indicates one of two things. The line is not tight coming from the filter for oil pressure reading or you have a hole in your vacuum diaphragm leaking oil as well as air into your ignition shut-off valve.

__________________
"Tell me and I will listen, Teach me and I will learn, Show me and I will accomplish, Involve me and I will succeed."
'84 300SD 256,000 Gold on Brown (Mileage Award)
'86 300E 246,000 Blue on Tan

Oil in the vacuum switch at the forward side of the starting key mechanism comes from a failed diaphragm in the shut off valve. The failed shut off valve on the injection pump then allows oil to be drawn into the line from the switch when you attempt to shut the engine off. Makes the rubber sleeves that connect the lines to the switch get gooey and leak. On one of my 240Ds this little problem leaked quite a bit of oil onto the underside of the footwell extension of the dash, which then leaked down along the driver's side of the center console, leaving a nice black oil stain.

You probably don't need the valve, just the connector sleeves. It doesn't hurt to clean it all out either as chances are there is still oil in there.

That's been my experience, anyway. Hope this helps.

Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

my emergency shutoff does work. I changed out the 2 little hoses at the valve by the key. It still does not shut down using the key, only by popping the hood and using the emergency shut off.I would like to change out the valve at the key, as I am sure it probably needs it, I am just not sure the easiest way to get it off. I am sure the pump needs it as well, I plan to do that in the next few weeks. I may even change the gasket and master shutoff, again, as well.

I changed the connector sleeves. they were pretty funky, it still does not shut down on it's own. I replaced the master shutoff and the gasket about 2-3 years ago. Would it go bad that soon? when it went bad the last time, it showed signs that it was getting ready to go. This time it was only a couple of times that it would not shut down on its own then it just stopped. THis occured when my master cylindar went bad. I replaced the master cylinder and the brake booster, hoping that would solve the problem, but it did not. I have also gone through all the lines and replaced the ones that looked bad enough to be replaced.

Well, you can try the "suck on the vacuum connection on the top of the shutoff valve" test to see if that works, just to eliminate the shutoff valve itself. If that is ok, you have a leak and the leak can be anywhere between the source of vacuum, and the valve.

My experience has been that the rubber connector sleeves and "Y" fittings are the problem more often than the hard plastic lines, but as things age, and you push the stuff around while changing the oil filter or adjusting the valves, you can split a hard line and not be able to see it. Ok, if you are an old fart like me, you can't see it.

So, the list of suspects goes from the tap to the vacuum pump to the key switch, through all the fittings and plastic lines, including the check valves (they fail too, and if they do, buy a Ford part as they are cheaper and work just as good if not better) then back to the injection pump shutoff valve.

If your locks work the problem is not likely elsewhere in the system. If your locks don't work, you may have a massive enough leak elsewhere that you cannot apply vacuum as the source is being undone by the leak. In general that would also make your brakes feel unresponsive as well.

I have had oil get into the key activated vacuum switch before and never had to change it. Just changed the couplings. And other times I had to change vacuum lines and couplings in and around the area where the vacuum supply comes in.

Good luck,

Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)