Just a quick pictorial on a how to rig up a temporary solution to a shutoff valve malfunctioning due to vacuum leaks in your system. This will only work if your shutoff valve actually holds vacuum, otherwise you will still have to lift up the hood and press the shutdown switch.



- Connect a vacuum tube from the shutoff valve (red tube).



- Then run the vacuum tube into the cabin



- And connect to a hand operated vacuum pump (or just suck into the tube if you don't have a vac pump, although I recommend getting one as soon as possible). Doesn't need to be a lot of vacuum, 10-20hg should do it.

This should help those of us that have vacuum issues and don't want to open our hoods every time we need to shut the engine down.

Good luck and happy wrenching!

Mick

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1980 300SD, 190K miles -- Soon to be on WVO
1989 GMC Suburban 6.2L diesel on WVO and B99

I did a bit of testing and the shutoff valve on my '76 300D only needs 7" hg to shutoff. Also found out car behaves really wierd if you reverse the lines on the ignition valve.

It's also possible to let that vacuum line exit the hood at the cowl and just give a suck on it.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Wouldnt it just be better to fix the problem? You can just plug off the offending systems if your door locks etc are leaky.

If the problem is in the ignition lock housing it isn't too bad to pull and replace the vacuum part of that either.

It looks intimidating at first, but I really didn't find it to be.

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

That's what I was thinking. The only relavance this would have is if you pump is out, but even then , I think bigger problems would arise. It seems like less work to just fix it if the valve itself is OK.

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1989 300E 144K

It's just a quick temporary solution until you get a chance to trace down a vacuum problem. For instance, it may be the middle of winter, you disovered a leaking pod in the climate control system and you don't want to disconnect the climate control system and you're waiting for some new pods to arrive so instead of opening the hood every time to shut if off, you use this alternative.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Point taken. But, if you had an automatic, wouldnt it go to slam-shift mode?

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

This is a temporary solution. Next time I get a chance to trace down all of the old vacuum leaks then this solution wont be needed anymore. This takes about 5 minutes to install and is a lot quicker than spending a day tracking down vac leaks. Its not for everyone but it definitely helped me out.

My apologies, I meant 10-20cm HG of vacuum, 7 Inches HG is perfect.

Mick

__________________
1980 300SD, 190K miles -- Soon to be on WVO
1989 GMC Suburban 6.2L diesel on WVO and B99