For the shutoff, I suggest pulling the brown vacuum line from the back of the shutoff on the IP while the car is running. Suck on it and see if the car stops. If it does not OR if you end up with a mouthful of oil, replace the shutoff. Do a search here on how to change it (carefully)

__________________
80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

I finally got under the hood and pulled the vacuum line off the brake booster. Hooked up my hand vacuum gage and OK. Left the vacuum line not donnected and turned off the key. Nothing. Pluged the vacuum line and engine stoped instantly. This took five minutes. I sprayed PB Buster on the nut 24 hours ago. So I know the vacuum pump works, check valve to the brake booster works and now can continue downstream.
I believe I have a vacuum leak in the door system, AC/Climate and a shot master brake cylinder, but only time and dirty hands will tell!

Next time you go to the junk yard, pull the ignition switch from any car similer to yours. You will notice a vacuum line attached to the lock cylinder. I had to replace my lock cylinder so my car would shut off with the key. The lock cylinder was the cause of "no vacuum shut off". I also traced the vacuum line and found a bad vacuum diaphram too.
If the junk car still has the engine in it, look to the front of the engine on the right down low for the vacuum pump. There is a diaphram inside that tends to fail. When it does you will notice oil spittin' inside your air breather. The oil also contaminates most if not all of you under dash vacuum diaphrams. Alot to clean out if this happens. But it can be done.
I learned alot with my first Mercedes. It was a 1980 300CD. I found a shop manual on CD at EBay. Learned alot more! Not too expensive. Give it a try. Go to EBay. Click on EBay motors. And click on manuals/literature.
Good luck.

__________________


Selling used Mercedes parts on Ebay...always changing...
cdplayer51 take a look!
____________

Pull the large vacuum line at the brake booster. Start engine & check vacuum at this line. My 79 300 SD has 25 whatevers on this line.
Do you have a manual, hand vacuum pump for testing 'circuits'? If not, get one and 20 or so golf tees. Start labeling lines and plug them till you find the buggers.
I have posted requests for a vacuum diagram for this year/engine on the diesel page. My CD manual does not have the diagram. Vacuum line color codes should from a 78 or 80 should be similar.
Driver's door locks: Yellow with green stripe = unlock, Yellow with red stripe = lock, Solid yellow = vacuum from pump.
There is a roughly 2" dia 'o' ring between the master cyl. and the brake booster that seals the vacuum. You can pull the master cyl. out enough to get at this 'o' ring without removing the brake lines. A common o ring will work.
Blowing hot air is default mode.
BTW: I found 1 qt of brake fluid in my brake booster!

diametricalbenz
Booster had 1 qt of brake fluid!
Rebuilt the master cyl.
New 2" 'o' ring.
Vacuum line to booster pulls 25 on my minni vac.
Brake boost is not working. Car stops with major foot effort and feels like it will never stop. I can lock up the brakes but my right leg will soon need a larger pant size.
Engine keyed shut off and door locks have gone by by so I'm chasing the gremlins.
How can I verify if the booster diaphram is ok?
Tomorrow I will verify the check valve and see if I can draw enough vacuum with the mini vac hooked up directly to the booster and disconnect every vacuum line but the ign. switch.

ok so I have the same problem with my '80 sd. I guess rebuilding the vacuumpump, new o-ring between booster and master cylinder, and get rid of the excess oil in the booster should fix it then, having read the thread. or is there more... the booster is a ***** to take off.
hot air that can't be shut of is usually broken climate servo. I bypassed that POS with a ball valve in the hot line.

1. shut off vale was bad replaced now ok
2. door locks fix bad rubbers in doors now ok
3. a/c recharged and now working ok

thanks for all your help ante

Do you work for the a oil company?
????? know lots of folks w/ 300d and sd who bought the cars especially because they love the veg oil. They run cooler, cleaner the turbos really love it. you do loose a bit of fuel economy but if you are making it yourself than it's almost free anyway. Will run just as many miles ( original diesel ran on hemp and other veg oils. american tanks during WW1 where designed to run on hemp , check out "Hemp for Victory") and yes I have done lots of research at the library and with experts, the internet groups are too unreliable (like people telling you that WVO and biodiesel are dirty junk fuel). As long as you filter the WVO very well and get all the water out of it your Benz will more than "tolerate" WVO, I have decided to refine my own Biodiesel at home, but my first choice was to convert for WVO (decided I didn't want to put the extra equipment on the car).

Ive been running various mixes in a crusty '79 300SD. The lastest summer blend is 25% Rug in 1 micron WVO. This is filtering way past the requirements for MB fuel.
In the last three years, I've studdied problems with alternative fuels and the WVO fuel (not biodiesel) issue is spray pattern allowing droplets to hit the far cylinder wall, causing upper piston seizing. Thining the WVO with RUG seems to help, but there is little data on this.
In cold weather (<10*F), these fuels will have to heated to flow and heated to 150-180*F to properly spray. There are atlernative nozzles, but I have no experience with them.
Two tank systems allow purging with diesel and some will even meter diesel to your conditions.
What I have done in the past is to blend to the weather conditions.
Soon I'll be making a batch of biodiesel to test in residential heating and the MB and yes I realize the rubber and solvent issues.
But the main issue here is there are at least 20 folk on this site who regularly burn some sort of alternative fuel and we seem to be able to do all the normal vehicle things with many different fuel formulation and processes. Now add all the other folk burning WVO ... that's a large enough population to gather reliable #s and to date there is not a rash of siezed engines after removing the blatent foolish things some rookies have done.
Quoting the origional diesel's fuel and assuming this will work in a almost modern diesel is a iffy argument at best. Yes my MB will burn hemp and lots of other oils but it was not designed to use those fuels.
If you look at all the iffy practices mordern fuel suppliers commonly use to increase their profits (and to hell with the consumer), you may add dino fuel to the list of aternative or experimental fuels when compaired to the fuel available in 1979.
Things change and home brewed fuel and dino fuel quaility will allways be a moving target, but as in everything, you never know till afterwards.

No, I don't work for an oil company, but I work very hard on my Benzes. I want them to last my lifetime (which ought to be another 20+ years, I hope). I do not want to be rebuilding my OM617 engine for $3K or more ( and the supply of used engines at boneyards will be a thing of the past as more people experiment with this stuff). I am not saying that there aren't responsible people out there using WVO and Biodiesel. I myself have a few gallons of the crud settling for use. However, I will be putting it in my VW Rabbit Pickup, which has an engine that will likely need a rebuild in 50K miles anyway. If that engine's demise is hastened by the use of WVO, well, OK, it will fund the rebuild. I can buy pistons for $40x4 for that vehicle vs $120x5 for an OM617.

I just really appreciate the qualities of the W116/W123/W126/W115 diesels and hate to see their numbers diminish because some yahoos , who know nothing about these fine cars, are considering them as a disposable transport, fueled by cheap or free fuel.

My comment was directed at the OP, who seemed to be in that category.

Rick

__________________
80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

i need some help i got a new tie rod center and damper in the mail. was able to get the old one out but i try to put the new one in and cant get it in.. i line them up on the floor and the old one is slightly bent. where the new one is Straight can it be wrong part or my car bottem is bent.. pic will help if you have any....