Just made purchase of a 1984 300 dt ,runs well with around 230k.The vacuum pump is out ,the car wont turn off with out opening the hood ,thats nice. Ran a couple of 6 ft vacuum hoses from the vacuum turn off at the alda to inside the car,the hose runs nicely along the drip rail to the back window slightly opened,the hood ,at its corner ,allows hose travel out the engine area.The trick is a mighty vac hand pump sitting on the passenger seat,very backyard mechanic ,but it works.My main question is the vac pump on the front of the engine not working ,will this harm anything with it out?

"Out" as in the guts are physically removed from the pump, or "out" as in non-working?

If the latter, you don't want to chance dropping small parts of the pump into the engine.

The alda conversion sounds interesting. Drove a 123 with the booster defective once. Brakes were not really good enough for any kind of sudden stop. No vaccum no booster and not really hard to get a used pump or kit for what you have. I think other than the weak brakes there are no other safety issues. Also the vaccum is required for the automatic transmission. You have to fix it eventually anyways as well so why not now?

My mechanic has an easier remedy ,just dissconnected the hose at the junction near the key ,took 4 ft of hose ,the mity vac hand pump and five minutes.I turn the car off first when ready to kill the engine,pump the handle 3 times and thats enough to pull vacuum on the turn off piece in the IP.No more hood raising in the parking lot ,people look at you like ,man what a piece of junk ,and I smile back and think to myself ,these people have no idea of what a good deal these old mbs are,not to mention no monthly payments to the AUTO GIANTS.Paint , some a/c and vac line repair, Ill have a very reliable machine.

I rigged up a tube for a customer of mine temporary and he had to suck on it to get it to stop. Funny times!

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1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

power brakes, driving it in it's present condition IS NOT SAFE!

There are many on this FORUM who will help you fix your vintage MBZ including me, but I for one will initially ONLY help you resolve the brake issue !
Sorry, but as a retired safety professional, this is my brand of "tough luv"!

Sam

Well, so far I have not seen any report of any kind of testing with a vacuum guage, or otherwise, to determine that the pump is "out".

More than likely, on your car, it is a leak in the door lock system causing the problem. The door locks are easily separated from the rest of the system and then there wouldn't be a need for all of this ghetto-rigging.

It really is a pretty easy system to fix and often takes less time than "rigging" something that may be hazardous. You already have the mightyvac!

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Sam

84 300SD 350K+ miles ( Blue Belle )

"SD Blue" is right on, how do you know your vacuum pump is out and then we can go from there. Have you taken a vacuum reading from one of the "T"s that branch off the large line that runs from the pump to the brake booster? If that is not reading 15 or more inches of Hg, then plug up the other lines and see what it is. We need this kind of information so we can help.
Best regrads,
Sam

i could totally make a dirty comment about that one man

If your vacuum pump is really not working (you'll know it if you get 'hard' transmission shifting and weak/non-functional power brake booster), you could get motor oil forced into your brake booster line. So aside from the obvious hazard of a hard brake pedal, there really is some potential for collateral damage to the power brake system if you drive around with a bad vacuum pump.

I agree ,you are likely to damage something or someone.There are plenty of folks who will roll up their sleeves and help you out.

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85 300sd SOLD ,85 745i,95 740i,1972 Suburban,1938 International

I replaced the diaphram in the vacuum pump of my 240d. Within a few months the vacuum pump stopped working again. Could I have put the diaphram or a washer in backwards? A new diaphram has been sitting in the trunk for over a year.

Door locks don't work, and the brake pedal is pretty hard, but the transmission shifts just fine. I hold down the brake and release the clutch to stall the engine. (No wonder it shifts OK)

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69 220D not running
79 240D parts car
80 240D Beater runs everyday
81 300TD temp disabled cooling problem
82 300SD sweet