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Old 06-23-2002, 02:40 AM
Posts: n/a
Unhappy vacum headaches

why does this have to happen to me? first the arabs fly the planes into the buildings and now the damn car wont cutoff

i replaced the shutoff silenoid, still dont cutoff.....i feel vacum when i pull off the tube to the plastic piece on the top of the pump, but dont wanna replace that if IT, too, isnt the problem.

what should i do?? :the doors and ac always have been weird. i replace a few tubes that looked plugged up, and i havent looked in the doors. jim morrison..........:p

this has had me constant for nearly two months tryin to finger this out my wife is gittin tired of opening the hood 5 times a day, and i wanna go to the lake and relax.......... :
hep me hep me hep me...............

R. Vincent Beaty, Chairman
CLUB R. BEATY, Houston
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Old 06-23-2002, 08:57 AM
engatwork's Avatar
Join Date: May 2000
Location: Soperton, Ga. USA
Posts: 11,997
You need to try and do some systematic troubleshooting on the vacuum system. Just because you have some vacuum it may not be enough. Purchase a "Mighty Vac" from a local parts house and start testing vacuum throughout the system. You will need to disconnect the vacuum lines next to the brake booster and plug the line that is "supplying" vacuum to the lines going through the firewall. This will get the doors and body vacuum elements out of the picture. Now see what kind of vacuum you've got under the hood.

Also - for future post please word them without using cuss words. You should be able to get your point accross without them and you will get alot more help on the subject you are requesting information on.
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Old 06-23-2002, 09:15 AM
84300DT's Avatar
Senior Member
Join Date: Jan 2002
Location: Mass.
Posts: 2,218
recent car not shutting off story

was on an errand mission/many stops/starts ambient temp over 80 deg f. all was well until final trip home and car would not shut off! checked vaccum line to shutoff valve - ok attached. tried
pulling line and replcing again - no shutoff. door locks and trunk-fuel fill door working.

ending up replacing small extension hose from shutoff vacuum line to shut off valve with a smaller diameter one. car shuts off!

hope above helps
1984 300D Turbo - 231k....totalled 11/30/07 RIP
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Old 06-23-2002, 09:24 AM
84300DT's Avatar
Senior Member
Join Date: Jan 2002
Location: Mass.
Posts: 2,218
oh btw rivirobo , am guessing your shutoff problem was referring to your 85 300D ?
1984 300D Turbo - 231k....totalled 11/30/07 RIP
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Old 06-23-2002, 02:39 PM
Registered User
Join Date: Aug 2001
Location: Evansville, Indiana
Posts: 8,150
The vacuum swith on the key switch can be bad, but if you are also having trouble with the door locks, I'd guess you have a more general vacuum problem.

You will need a MitiVac or similar hand pump with guage.

Connect it to the main vacuum line from the pump to the booster and run the engine at idle -- you must have about 11" or so of vacuum. If not, you have either a leak or a bad pump.

To check the shutoff, connect it to the brown plastic line that runs from the main vacuum line and pump to see if it holds vacuum. If it does, switch the key on and off while operating the pump (or just switch the key then go back under the hood and pump) -- if the stop lever goes down and stays down and holds vacuum on the hand pump, you have a vacuum supply problem.

Same thing with the door locks -- the yellow plastic line that goes into the dash is the vacuum supply. Hook the pump up to that and pump -- it will take a while, there is a vacuum tank you will have to evacuate -- and see it the locks work. If you can't pull a vacuum, you will need to pull door panels and see what is leaking. The locks operate off a vacuum actuator with a yellow with red and a yellow with green stripe hose. The yellow line from the engine goes to the vacumm switch in the driver's door (no actuator in that door). A broken line or bad diaphram in one of the doors, the trunk, or the filler cap, will cause the locks not to work properly.

More details under various postings for door locks and vacuum shutoff. Fairly easy to work on with the hand pump, other than removing and replacing the door panels.

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!
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Old 06-24-2002, 06:15 PM
Registered User
Join Date: Oct 2000
Location: California
Posts: 209
Here's a method posted by IceSailor for checking interior vacuum leaks without a Mityvac tool:

82 300TD A/C problem
1995 C280
1999 Triumph Daytona 955I - my speed fix.
1982 300TD - Gone, but not forgotten.
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