With the weather turning colder and old plastic getting more brittle, I'm having vacuum trouble with my 300D. It still turns off, but it takes a good 30 seconds after I turn the key off. I thought I fixed it today by changing the little rubber piece that mates the brown/blue line to the shutoff solenoid. No joy. It really doesn't help that the whole system is so old that looking at it is almost enough to trigger a leak. I'm picking up a box of golf tees and some different size hoses tomorrow. At least we have the vacuum diagram sticky

I was considering ranting about what a bad and ultimately doomed idea it was for the DB engineers to run so many things off vacuum, but then it occured to me that the car is 26 years old and that electrical, air, or mechanical solutions would probably not be doing any better at this age.

Rant over

Any tips to make my vacuum life easier?

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 401,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 26,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.
99 Mazda Miata 183,xxx miles.

I just bit the bullet and switched out all the old rubber connectors with new and checked all fittings for cleanliness and tightness, Replaced leaking pods and actuators and have been trouble free so far.
It was worth the peace of mind not to mention proper vehicle operation to git 'er done.

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1981 240D 143k 4 spd manual -SOLD

2004 VW Jetta TDI 5 speed 300k -still driven daily

Besides other things it could be the Vacuum Switch on the Steering Wheel Lock (some more rubber hose ends there also).

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84 300D, 82 Volvo 244Gl Diesel

Sucks, doesn't it?

I too replaced all connections under the hood. I took out all the plastic hard vacuum lines and spray them with brake cleaner, let dry and reinstalled. That was many years ago. Recent vacuum work I had to do, was replace the shutoff solenoid itself. Since that had the potential for a runaway, I had my mechanic do it. He had more experience than I did.

Get a hand pump w/ a gauge and see which ones do not hold vacuum, while you'll be out getting golf tees. Once you start pulling connectors, vacuum is hard to "collect" since they "leak out" when you disconnect.

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http://farm8.staticflickr.com/7271/7...144c3fc1dc.jpg

my 240d if having the same shut off problem, been replacing lines and hoses left and right and still no solution, haven't tried the ignition switch lock yet . let us know what u find

I was having the shut off problem myself on my '85 300D as well as the door locks. Using a Mighty Vac I was to rule out the door, trunk actuators. Line and rubber connectors all holding vacuum. Except one, the drivers door master switch. I plugged the yellow line with a golf tee and the engine shuts off! I replaced the master switch and...the problem persist. Thinking I had a defective part, I replaced it with another. The door locks still do not work! Am I missing something? I have done a lot of research on the previous posts to no avail.

Check the line only. It could have a hairline crack or not making a good seal on the master switch. Also whats the vac from the main vacuum pump?

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92 300D 2.5L OM602 OBK #59

besides replacing every connector and being done with it, I've used clear silicon caulking to seal up weak connections. A light smear all the way around the plastic tubing then spin it as you insert into the fitting... works pretty well if you're the impatient type.


...it will come apart if you need it to, just use clear silicone.

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I suspect I'm having vacuum issues as well, and I always hear of people using MityVac's to check. Does it also allow you to "add" more vacuum? And what model do you buy to use on an 82 300SD?

I love my Mityvac. Yes it does let you add more vacuum to test a line.

I HIGHLY recommend you get one. Have it under your pillow and ready at a moments notice.

I had a leak in my front right passenger door. I haven't taken the time to fix it yet so I isolate the lock line. That fixed my leak and now my engine turns off.

Once I gather the courage to open the passenger door for some discovery I will fix it.

Until then at least the door locks when I turn the key

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-Typos courtesy of my mobile phone.

bxfl, anyone/brand will be fine, the more accessories that come with the better, lets you bleed brakes among other things.
okyoureabeast, the SD has a separate door lock system, bxfl, where is your problem?

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83 SD

84 CD

Mityvac is a brand name of Vacuum Tester that you squeeze a lever to develop Vacuum. There are other companies that make products that are functionally the same; like Coke verses Cola.
I suggest you get an all Metal one instead of a plastic one. I have had my Actron all metal Vacuum Tester since the early 80s and it has survived much rough hadeling. I am not sure a plastic one could have lasted that long.
Harbor Freight sells their version for around $20.

Also the MightyVac company sells many types of equipment besides the hand held Vacuum Tester.

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84 300D, 82 Volvo 244Gl Diesel

Thanks for the suggestions JT/20 and Bobodaclown. I will check the lines individually and replace with fresh rubber connectors. I checked the Vac some time ago and vac off the pump was erratic, I then placed the gauge off the brake booster and got strong steady vacuum. I believe it was 19mHG. I kept trouble shooting each individual component. I replaced the yellow check valve, due to a pin hole leak. That is when I discovered if I plugged the yellow line the engine would turn off as it should. I also figured out the the vacuum canister in the trunk was leaking around the rubber grommet. Using JT/20 suggestion I smeared some silicon around and vacuum held. I pulled the carpet up on drivers side and checked vacuum for and aft. All held except the master vacuum switch lines. Thinking I found the culprit, I replaced the master vac switch and now I am on the 3rd one as I was thinking of defective part, but now not so sure.

Here's a really good thread:

http://www.peachparts.com/shopforum/showthread.php?t=117168

My vacuum issue seems to be with the drivers side door and possibly further on. The drivers side door no longer locks using the key - I can only lock and unlock it from the inside. I suspect I have a leak.

Earlier I thought I may also have a leak somewhere along the transmission line because I really have to "stomp" on the pedal to get it to go, but I wonder if that's just the nature of the car? (My first diesel).