Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help




Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 01-09-2004, 03:39 AM
84W123DT
Guest
 
Posts: n/a
Premature Loss of Vacuum to Door Locks

I use to be able to lock and unlock all the doors, trunk lid and fuel door, on average about 5 to 8 times after the engine has been turned off. I am now down to about 2 times due premature loss of vacuum.

I will be replacing soon the leaking Shutoff valve at IP (evidence of oil in the vacuum line, luckily captured by the pre-filter I installed like Thomaspin) and Iím wondering if the two are related or coincidental? Should I look anywhere else? I have a MityVac and will be troubleshooting for vacuum leak.

Your $0.02 is appreciated.

Last edited by 84W123DT; 01-27-2004 at 03:04 AM.
Reply With Quote
  #2  
Old 01-09-2004, 09:49 AM
Rick Miley's Avatar
Spark Free
 
Join Date: Jun 1999
Location: Land O Lakes, FL
Posts: 3,086
There should be a check valve that isolates the lock system from all other vacuum consumers. It has three ports - 1 on one side and 2 on the other. The single port goes to the vacuum supply, while the two ports go to the vacuum reservoir and the lock circuit. If this is connected properly and the check valve is working, then the door locks would not be affected.

Now that I've just typed all that, if the shutoff is leaking so bad that you're not achieving maximum vacuum in the reservoir, say only 10" instead of 20+, then yes everything would be affected.
__________________
Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References
Reply With Quote
  #3  
Old 01-09-2004, 10:06 AM
adamb's Avatar
Registered User
 
Join Date: Jul 2001
Location: Chapel Hill, NC
Posts: 321
Additionally, the shut-off valve should be isolated when the car is in the run possition by the valve in the key switch. If your system was suckign oil through the shut-off valve, perhaps flushing the lines and replacing the connection at the key switch would be good, too.

I recently bought a shut-off valve from Performanec products, and it had "Ronak" on it, and it was DOA. It didn't hold any vacuum and trying to pump it wouldn't even budge the arm. The reason I didn't order it from here is that the website said that they weren't available. Of course I determined this after I installed it. From this I learned to check every part I get before I put it in.
Have fun,
Adam
Reply With Quote
  #4  
Old 01-09-2004, 05:53 PM
84W123DT
Guest
 
Posts: n/a
Rick: Is the check valve the "yellow" thing with the yellow vacuum line?

Adamb: the "ronak" shutoff valve I received seem to hold vacuum. See thread: Shut-Off Valve @ IP aka Vacuum Control Unit or MB FSM-EPC = shutoff box
Reply With Quote
  #5  
Old 01-09-2004, 06:02 PM
Ibe300D
Guest
 
Posts: n/a
Yes, the 3 way check valve is yellow. Im also working on a vacuum shutoff problem, which i believe is almost solved. BTW, Phil does have them, its a PartsShop item,
# 000 070 20 53 ...its 43.00
Reply With Quote
  #6  
Old 01-09-2004, 06:04 PM
Registered User
 
Join Date: Oct 2001
Location: st paul, mn
Posts: 284
How's your brakes? I searched for a vacuum leak which kept getting worse. In addition to the shut-off valve my brake booster was leaking. Gradually got worse and worse. Vac bled off slowly til I hit the pedal and then it would just plummet. Because it happened slowly I did not realize how firm my pedal had gotten until I got another 123 (which donated the booster in addition to the engine).
__________________
andy t
'78 300d
'95 volvo 850, wagon
'86 300sdl - engine out, maybe I'll have it rolling by June

whole bunch o' bicycles
Reply With Quote
  #7  
Old 01-09-2004, 06:12 PM
Ibe300D
Guest
 
Posts: n/a
Guru, I think my brake booster is the culprit as well! when I take the main vac line out of the booster and plug it with my thumb, the car will shut off! I also have to replace the IP shutoff valve again because the one i got from Phil was unfourtunatly defective. It took several pumps to pull the arm closed, while a good one will pull it closed almost immediately.
Reply With Quote
  #8  
Old 01-09-2004, 07:02 PM
84W123DT
Guest
 
Posts: n/a
Quote:
Originally posted by wheelguru
How's your brakes? ...
ALL functions appear to be normal other than the premature loss of vacuum noticeable by the door lock issue I have currently.

I have so far replaced the loose 4-way rubber connector to the check valve and have ordered a check valve from the dealer.

FWIW, all these symptoms and malfunctioning started when I noticed oil in the pre-filter I installed in the shutoff valve vacuum line. I will be having the leaky shutoff valve replaced by a garage (concern about the runaway engine) soon. See what happens and hopefully should fix the problem.

Installed a filter on the line, recommended.
Attached Thumbnails
Would a leaking Shutoff Valve at IP cause a quicker Loss of Vacuum to Door Locks?-oil-vac-line.jpg  
Reply With Quote
  #9  
Old 01-09-2004, 07:18 PM
84W123DT
Guest
 
Posts: n/a
Quote:
Originally posted by Ibe300D
... while a good one will pull it closed almost immediately.
I just purchased a "ronak" shutoff valve, using the MityVac, it takes two full pumps to fully-retrack the lever and holds vacuum. See photo: Shut-Off Valve @ IP aka Vacuum Control Unit or MB FSM-EPC = shutoff box
Reply With Quote
  #10  
Old 01-09-2004, 07:32 PM
Ibe300D
Guest
 
Posts: n/a
Exactly! We also went to a local dealership and tested one there, it also fully closed with 2 good pumps. WM20650 is my brother and were working together on this car, see my sig.
Reply With Quote
  #11  
Old 01-13-2004, 12:37 AM
84W123DT
Guest
 
Posts: n/a
Quote:
Originally posted by Rick Miley
... if the shutoff is leaking so bad that you're not achieving maximum vacuum in the reservoir, say only 10" instead of 20+, then yes everything would be affected.
Rick:

Your troubleshoot of my problem is correct. I just had the Shutoff Valve at IP replaced today and my door locking/unlocking functions are back to normal (about 8 times before I exhaust the residual vacuum after the engine has been stopped).

BTW, I tested the old leaking Shutoff Valve and the lever fully-retracted after two full pump strokes on the MityVac (still able to shutdown the engine) but does not hold vacuum.

Thanks for the help.
Reply With Quote
  #12  
Old 01-22-2004, 03:48 AM
84W123DT
Guest
 
Posts: n/a
Question Cold ambient temp = faster loss of Vacuum ???

I seem to loose vacuum (for the door locks) more rapidly when the car is outside on a cold day as oppose to when the car is in the garage. There's only enough vacuum to last the locking and unlocking of the doors for about 3 times post-engine shutoff.

I have just replaced the check valve (yellow) for the door locks and shutoff valve. I don't believe that there is any further vacuum leak in the system as it locks and unlocks all the doors about 8 times post-engine shutoff when it is inside the garage.
Reply With Quote
  #13  
Old 01-22-2004, 09:57 AM
adamb's Avatar
Registered User
 
Join Date: Jul 2001
Location: Chapel Hill, NC
Posts: 321
Awesome! I'm glad that you fixed the leak finally!
Pease do keep an eye on the Ronak shut-off valve as I had three that went bad within a week even though they tested OK when new. There was nothing I did wrong and when I called to get an RMA, the rep said they have experienced numerous problems with them.
Good luck,
Adam
Reply With Quote
  #14  
Old 01-22-2004, 10:12 AM
Rick Miley's Avatar
Spark Free
 
Join Date: Jun 1999
Location: Land O Lakes, FL
Posts: 3,086
Quote:
Originally posted by 84W123DT
I seem to loose vacuum (for the door locks) more rapidly when the car is outside on a cold day as oppose to when the car is in the garage.
Well, the system depends on rubber connectors to join the hard plastic vacuum lines, and those connectors must remain pliable to form a seal. I could see them becoming stiff and leaking a bit in really cold temperatures. Of course, being in Vancouver, your definition of cold is much different than mine!
__________________
Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References
Reply With Quote
  #15  
Old 01-26-2004, 02:17 PM
84W123DT
Guest
 
Posts: n/a
There is a Vacuum Leak somewhere???

1984 300DT

So far I have replaced all the visible rubber (3) 3-way, (1) 4-way and (1) yellow check valve vacuum fittings in the engine compartment in hope to cure the premature loss of vacuum for the door locks, but to no avail.

Referencing the vacuum diagram in the CD manual indicates that there are some more 3-way and 4-way rubber fittings (distributors) inside the car but where? I am trying to find the location of these distributors so I can hook-up a MityVac. Where should I be looking? Is it necessary to remove the door panels? I see vacuum lines under the front floor mat but no distributor.

Your help is appreciated. Thank you.
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 02:12 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page