calling vacuum guru's - PeachParts Mercedes-Benz Forum

nibiru · #1 06-14-2006, 06:52 PM

Howdy folks:

This being my 3rd or 4th post today

To clarify - this is an 82 300TD - I purchased alldata 4 the year
seems I have the vacuum system put back together allright

I purchased the complete vacuum kit form diesel giant -
Hooked up the 4 way to the outlet closest to the brake booster

Will all hooked up I am only drawing maybe 2" yet when I test my line directly I am getting 21" - as I am typing this I realize I must have a pretty big vacuum leak somewhere between either the ac control unit or the central locking system

Yet when I put the vacuum pump on the ac - green line - it pumps up to 25" and holds there

do you think I am on the correct path of thinking here - I feel I should have more than 2 " draw from those splitters- any idea what I should be reading
like maybe closer to 15"

Please and thanks in advance

peace

N41EF · #2 06-14-2006, 10:30 PM

Sounds like a big leak somewhere. I'd start splitting it out, ie Lines to trans, lines to egr, lines to locks. I found a big leak on the 3/2 switch under the black box on top of the valve cover. After fixing that I found several minor leaks to fix also.

#3 06-14-2006, 10:37 PM

You're on the right track, try blocking the line to the door locks and see how much vacuum you get. It's common to have leaks in the door actuators and the hose connections.

nibiru · #4 06-14-2006, 10:53 PM

howdy folks:

I already bloced off the EGR - I ran out to get some vacuum connectors
3ways and 4ways

Left the vacuum pump pumped up to 25" on the solid yellow line into the cabin thru the firewall. been gone a few hours and it has leaked out - this is the main line to master door lock switch I believe - so that could be a cause - but just to be sure I will test all lines again and reports back - already blocked off fuel door line as I found 2 small tears in the diaphram - waiting for that part to arrive- till then its me and the vacuum gauge/vacuum pump

Thanks for your input

Peace:

#5 06-14-2006, 11:08 PM

Quote:

Originally Posted by nibiru

Left the vacuum pump pumped up to 25" on the solid yellow line into the cabin thru the firewall. been gone a few hours and it has leaked out - this is the main line to master door lock switch I believe - so that could be a cause - but just to be sure I will test all lines again and reports back -

Take a look at my post #16 here for a description of the door lock system for a sedan, the wagon can't be too much different:

Strange central locking problem

nibiru · #6 06-14-2006, 11:33 PM

howdy folks:

Ok - preliminary results - cabin lines are secure I tested them at the footwell drivers side - tested the lines going to the master switch - red line pumps up to 25" leaks out 1" every 3 seconds - and the blue line to 25" leaks out 1" every 5 seconds - I do not think this is normal

SO this must be one of the problems - but I believe not the main culprit

now for the engine bay

#7 06-14-2006, 11:40 PM

Quote:

Originally Posted by nibiru

Ok - preliminary results - cabin lines are secure I tested them at the footwell drivers side - tested the lines going to the master switch - red line pumps up to 25" leaks out 1" every 3 seconds - and the blue line to 25" leaks out 1" every 5 seconds - I do not think this is normal

I agree, you have some leaks, the door lock system should hold a vacuum for days. One clarification, did you test the red and green lines "going to the master switch" or did you test the lines from the switch going to the other doors, or did you install a tee and test in both directions?

I also agree, that isn't a big enough leak to keep the system from maintaining a vacuum with the engine running.

Keep us posted.

nibiru · #8 06-15-2006, 12:56 AM

howdy folks:

Ok - round 2 - tested line from bottom of drivers door to master switch - both red and blue - leak at the master switch both lines - so I figure I must replace the master lock switch - leaks now 1" every 2 seconds

Now the interesting part- I decided to turn on engine to register how much vacuum I am getting to the solid yellow line - it shares vacuum in the yellow dash pot - connected in a 4 way with the ac ( green/ blue ) and the brown /blue to the ignition -

Engine ran fine - registered off the yellow at the top of drivers door where it would attatch to master lock switch - only 2" while running - now when engine shut down gauge registed 5.5" engine shut down immediate

ignited engine again - stayed at 5.5" - shut off engine - registered 11"
engine shut down immediate

tried to ignite engine again - would not fire - pulled the solid brown line off at the back of injector pump and engine fired - ran solid - re- attached line - turned key - engine shut down immediate - but would not ignite again until brown line pulled from back of IP- gauge remains at 11"

So from what I can deduce - these lines that run thru the firewall into the cabin should be holding only about 2.5- 6" of vacuum - or am I missing something - as I am blocking a line close to the source-

Careful - I have also disconnected the EGR lines so I have 2 golf tees inserted

any takers on this .........

I will study my 3 printed posts and 2 printed diagrams and dream of a proper vacuum system

Thanks again :

Peace:

#9 06-15-2006, 08:43 AM

OK, I think you may have more than one thing going on here. Based on your other thread you are getting oil into the vacuum system from the IP shut-off, now you are telling us the vacuum increases when the engine is shut off and you are having trouble getting it to start without disconnecting the vacuum line to the IP. That implies that there is something going on with the IP shut-off and/or the vacuum valve on the "ignition" switch. Is it possible that oil has gotten into the vacuum valve on the "ignition" switch and is making it stick? Have you checked the vacuum connections to the "ignition" switch under the dash? I think I would temporally block the lines to the door locks and work on the shut-off problem first.

nibiru · #10 06-15-2006, 11:22 AM

howdy craig:

thanks for the input :

Anything is possible - the ignition key cylinder is greasy underneath- so that could be a problem - I will investigate more today

before all this - it would shut off if engine was cool - when engine is hot - run- on for a minute or so - I did block off the entry - I thought . By putting the vacuum gauge on the solid yellow line

Now if I block off the both lines ( solid yellow & Yellow / grey ) I will increase vacuum to the ignition cylinder - yes
and will this be a problem ??

Is the ignition cylinder repairable or does need replacement?

All good questions

Thanks again:

Peace:

#11 06-15-2006, 12:18 PM

Your problem seems a little unusual because the car doesn't start sometimes, that implies the IP shutoff is getting vacuum when it shouldn't be. The only reason I can think of is the "ignition" vacuum switch. I would guess that it may be sticking open due to oil from the leaky shutoff valve, so I don't know if it needs to be replaced, or cleaned, or what.

You can see it in this photo, I don't know if the vacuum valve is available separately (maybe used):

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1CQ0J3JZ41TS0Q1M70&year=1982&make=MB&model=300-TDT-001&category=All&part=Ignition+Lock+Assembly

Regardless, I think you need to resolve the IP shutoff valve problem first, or you are just going to keep sucking oil into the vacuum system.

I don't see any reason you can't block off both yellow lines to the door locks, one goes to the "master switch" in the driver's door and the other goes to the storage tank. They do not affect anything except the door locks.

nibiru · #12 06-15-2006, 01:22 PM

howdy craig:

Thanks again for the reply and info/ input:

Discovered something this morning - I must eat better if I am to work well into the night

In my infinite wisdom - I bridged the 2 ignition lines to see how much vacuum I was receiving - that would expalin why I was building up vacuum and when I turned the key to off position I would get such a build up

I saw this as I was buttoning up the car to try and find a master switch - in Palm Springs I feel I may be at the mercy of the stealership- dunno - met a very cool guy who gave me a 3 way connector yesterday ( " dont worry about it - they are only a few pennies anyway" )after another guy charged me 5.25 each for a 4 way

figured which goes where - starts and shut down fine
Will put the gauge on the shut off and take a reading

Perhaps I am looking at repalceing the master key switch and replacing the IP shut off valve as where else could the key cylinder get oil

Let you know and thanks for the support

Peace

#13 06-15-2006, 01:48 PM

Quote:

Originally Posted by nibiru

Perhaps I am looking at repalceing the master key switch and replacing the IP shut off valve as where else could the key cylinder get oil

That makes more sense, the "ignition switch" is probably OK. You probably need to replace the shut-off valve, that's the only place the oil can come from.

http://catalog.eautopartscatalog.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=1CQ0J3JZ41TS0Q1M70&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1982&product=D2020-11537&application=000004567

Do a search on this, and be very careful about the potential of a "runaway" engine if it is not installed correctly.

nibiru · #14 06-15-2006, 03:33 PM

howdy craig:

Thanks again for the input

in retrospect is simple- I think the lines on the ignition were either crossed or needed to be resealed - now the car runs great - locks - shuts off , starts , shifts good

all that

I will change the shut off and replace the fuel door vacuum pod. as soon as possible
till then the gremlins seem to be at bay

Peace