Can someone help pour soul?
Initially lost climate control, auto locks, and engine shut off. Disconnected and plugged green/black line {climate control?}, from plastic tube off vacuum pump. Pump is OK. Able to restore autolocks, and shut off, but vacuum leaks down after engine shut off. I have MB Model 116 Service Manual CD rom, but find vacuum systems diagram are not helpful as far as locating component. Do I have a second vacuum tank in addition to the one in the trunk? Where do I get a miti vac? Any help is appreciated!!

A MitiVac can be found at any auto parts store, price is $35 up depending on exact packaging and parts.

Sounds as though you have a bad leak in the climate control AND at least one bad check valve. The valves are in the lines before the T in the engine compartment, up on the firewall. The can be replaced with any vacuum check valve, there are some for Fords that fit very nicely. Make sure you put then in right way round.

If a leaking climate control caused the shutoff to fail, chances are you have minimal vacuum from the vac pump. Check the hose for cracks, the white plastic part with the vac connections for cracks, and for a loose fitting on the pump itself. I would inspect the check valves on teh pump, too -- they can fail and you have little or no vac. Could also be a pump, but you need the MitiVac to check.

For the door locks, check the plastic lines in the driver's door, they crack inside the rubber boot. Supply line is yellow, opening is yellow with a green stripe, closing is yellow with a green stripe (I think, may have the stripes backwards). It quite likely you are due for some new lock diaphrams, too.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Peter: Thanks for your response. I have not done a credible job of troubleshooting due to lack of good vacuum source. I did change the engine vacuum pump and there was no change in performance. So- I assume the pump is blameless. Do you have any info on the second vac tank that the MB diagrams show? If its there, where? I will keep posting as progress unfolds. Guess this is the price to be paid for driving an oldie but goodie. Thanks again.

I know the tank for the door locks is under the left front fender, and there may also be one in the rear bumper or in the trunk, I'm not sure.

I believe the "other" tank in the rear may be for the climate control. Best way to check is the MitiVac hand pump, it's really the only way to troubleshoot the vac systems on these cars.

Check the plastic part in the main vac line carefully -- they get brittle by the age you car is, and crack. This will prevent much vac accumulation.

Also test the brake booster -- when it goes bad, you have little or no vacuum because it's all getting vented off faster than the pump can generate it. You may not have a hard pedal.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Peter I will search the area around the L F fender both outside and under the hood tho I can see no vac lines headed that way. I dont believe the brake booster can be a factor since I have excellent brake function. I will be held up pending getting the mitivac but will keep posting as progress warrants. Thank you very much for your suggestions.
Willie

Unless the car has been in an accident, I wouldn't spend alot of time looking for the vacuum reservoir. I haven't seen one fail in 30 years. I'd buy a miti vac and spend time checking all the lines that come together by the booster.

Peter

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Auto Zentral Ltd.

Hi Peter of California Just today got the vac pump. will be beginning the process of troubleshooting very soon. will likely have lots of questions to post. Of course the biggest problem that I foresee is in locating all the vacuum components;switches, air flaps and so on. I look forward to hearing from more of the good people on the forum. Fortunately, the climate control system defaults to the defrost function so I can still get heat(too much) in this cooler weather. Thanks for your input ,Peter

Willie

Trouble shooting installment 1
The mitivac is super! decided to investigate the autolock system first since that appeared to be the easiest way to go. the locking system appears to be leak free. I tested on the locked as well as unlocked functions and vacuum held for several minutes.this was done at approximately 15 in of mercury(1/2 scale on my pump).In addition, I determined that the engine shutoff,transmission line and cruise control were leak free,as well as the vacuum tank. Incidentally,I could find no evidence of a second vacuum tank near the front drivers side. I could not get ANY vacuum to the white line (no stripe) that goes into the passenger side body near the brake booster. Poor Soul has not a clue where this line goes or what its function is. Does any one have an idea what I should be looking for? HELP!!!!!
Willie
should read driver's side body near brake booster

Poor Soul reconnected everything back to original hookup using all new connector fittings; (rubber connectors, 1 to 1,1 to 2s and 1 to 3s)all original lines were used. Engine shutoff and heater function seem to be fine now. Have not verified if the AC is operational this installment.As connected the vac on lowest line is at about 18 in.HG . HOORAY ! How lucky can you get.
Installment 3 upcoming.



1980 300 SD about 200 K miles Engine about 70K miles total. newly rebuilt transmission.Body pristine.Oldie but goodie.

Aren't those Mitivacs neat? You can't beat the cost to value ratio of those things.

Peter

__________________
Auto Zentral Ltd.

Hi Peter of California I learned about the Mitivac here on the Forum. Previously had not known they existed. They are GREAT for this application. I am delaying troubleshooting for installment 3. It is pretty cold here in Northwest Connecticut just now and given the cost of heating oil I will give up garage activity in favor of the warm house.(I dont really need the AC in my car for a while). I still dont know the function of the white vacuum line mentioned in a previous message but it is connected and heater function works. Perhaps some of the more experienced members can give Poor Soul a clue. thanks Peter Willie

Yeh,
It's been pretty cold out here too. We're getting down to the high 30s and low 40s. This cold snap should end in about a week or so. I'll take a look at a vacuum line print for that year model and let you know what it's for.

Peter

__________________
Auto Zentral Ltd.

Happy Holidays to everyone: The day after posting my last reply the temp outside my door was negative 10 degrees.needless to say I have made no attempt at further troubleshooting. However, upon further examination of my MB service CD I have found lots more good information that I had missed before. Am very hopeful this will be a help in getting complete system back again. Will be interested to see if functional vacuum system will improve a harsh upshifting problem when there is no load on the drive train. If it does
not I will post specific conditions hoping for help from the forum. Cheers
Willie

And now its about 50 degrees outside my door. I checked on my ac compressor yesterday. (would not run) Found near 12 volts on both sides of the pressure switch that is in series with the clutch. Disconnected the plug from the clutch and measured across the clutch terminals and found continuity of something over 100 ohms. reattached plug and lo and behold clutch now activates.AC works fine. Problem solved. Will spend this new calendar year with fingers crossed. Happy new year to all.
Willie