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  #1  
Old 10-23-2008, 09:56 PM
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Too much vacuum?

Hi Guys, my name is Tom
1982 300d manual 4 speed non-turbo.The only thing connected to my vacuum pump is the brake booster.Does anyone know of a valve or some way that can release excess vacuum?Thanks

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  #2  
Old 10-23-2008, 10:15 PM
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Why do you think that you have too much vacuum?
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  #3  
Old 10-23-2008, 10:29 PM
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Hi Matt,
well if the vacuum pump keeps vacuuming without release maybe the diaphram will give or the booster might get damaged
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Old 10-23-2008, 10:49 PM
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I have disconnected the vacuum engine switch-off and use a push/pull cable.Also the doors still lock and open from inside without vacuum and the drivers and passenger side doors unlock with keys from outside anyway so now there is just the large tube from the vacuum pump to the brake booster.At high revs maybe the vacuum might be too much?
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Old 10-23-2008, 10:53 PM
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There is no such thing as too much vacuum.
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Old 10-23-2008, 11:01 PM
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I think I understand your question. You think without everything hooked up you have too much of a commodity. The vacuum to be specific. Actually the amount accumulated is determined by the pump design. If a good pump developes twenty inches of vacuum that is it's limit. You do not actually keep accumulating the commodity.

Once the limit is achieved it just stays at that negative pressure. If the vacuum or negative pressure is reduced by usage the pump restores it as fast as it can. If your power brakes are operating normally I would just forget it. Is this the kind of information you where seeking?
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Old 10-23-2008, 11:15 PM
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Thanks Barry, I was just worried about damaging the new diaphram or worse .
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Old 10-24-2008, 12:31 AM
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Vacuum is lack of atmosphere pressure. There is only a certain amount of pressure and that pressure varies by altitude from 14.7psi at sea level to 9psi at 14,000ft all the way to 0psi in space.
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Old 10-24-2008, 01:12 AM
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Quote:
Originally Posted by 82300d View Post
Thanks Barry, I was just worried about damaging the new diaphram or worse .
My choice of wording and description were very bad but the general gist was there. The best description I can really think of in a tired state is vacuum is the elimination of air molicules . Exotic pumps even round them up when the vacuum becomes really strong so that lesser pumps can grab them up and exhaust them from a chamber. These applications are to obtain really intense vaccums like exist 300 miles above the earth.

The pump on our cars is a simple single stage vacuum pump that can only remove a certain limited amount of the air molicules. In a strong vacuum even sound will not travel. Heat other than the radiant component like the frequencies that the sun emits to heat the earth are the only type of heat that will move through a strong vacuum. If say you put an alarm clock in an intense vacuum six inches away from you and it rings you will not hear it. There is nothing to vibrate to transmit the sound left.
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Old 10-24-2008, 01:42 AM
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Your ears would ring if it were that quiet. Go figure

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87 300D
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Old 10-24-2008, 01:56 AM
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...and then your head would blow up.
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  #12  
Old 10-27-2008, 06:05 PM
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Hi Guys,
clickety click click, I think I get it.the vacuum pump is not a suction pump or suction turbine.
I have had to buy a used vacuum pump which is different from the original(pulley line-up problems- original pump sticks out too far),the original had one pipe to the brake booster.This new/used one has two pipes-one to the booster and one to the aircleaner lid.
When i stripped the pipes from the scrap engine i noticed there was more than the normal amount of oil in the aircleaner pan.
Both pipes were coated with oil inside.on stripping the pump there was oil on the vacuum side of the diaphram.There was no visible damage of the diaphram but on stripping it the center hole where the allen screw goes was slightly enlarged with minute tearing and slight seperation of diaphram material but all the damage was inside the fine raised sealing rim on the diaphram sides of the big washers.This was not visible without removing the big washers on either side of the center of the diaphram.This did not seem to be too bad so i assumed the pump must be very strong.Maybe one of the valves were reversed because the pump did show signs of having been opened but i never checked before stripping.Apparently the scrap engine bust its timing chain.wow.The chain looks strong.
I was thinking maybe the double pipe pump was sucking oil via the aircleaner from the crank breather which also goes to the aircleaner but this is probably not possible.so it probably was leaking through the diaphram.
Maybe i am a bit paranoid but i have put a lot into this car and hope to run on wvo.
Thanks for all the free info -sorry i cannot buy any stuff as i am too far away
cheers,
Tom
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  #13  
Old 10-27-2008, 07:23 PM
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I have swapped the newer style VP (one line) for the older style pump, its cheaper to rebuild

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