Most Common W123 Vacuum Leak Sources?
 

Just curious as I am sourcing vacuum leaks on a '83 300D -what are the most common vacuum leak sources/parts on a w123? Members, cast your votes! Thank you!

The vacuum elbows under the hood (or anywhere else), the connection at the reservoir, the recirc. flap actuator, the fuel door actuator and master vacuum switch.

Door locks.

For me, the fuel door lock (I've replaced mine twice).

I second that, I had problems with those in two of three 300Ds.

The first few years after we bought the car, the biggest vacuum leak was the shop sucking my wallet dry :eek:. I didn`t understand the system, so kept taking it back to fix the constant, hard shifts, door locks not working or eng not shutting off.

I think it was a easy money maker for them, I drop it off, they Vacuum my wallet.:mad:

Once I found out how the Vacuum system works, piece of cake. hello mity-Vac.

The only vac problem the past 5 yrs has been the R/R door actuator. replaced that, and it`s been smooth sailing.

Now, what do I do with all this extra money? :) ;).

Charlie

Vacuum items that are either exposed to heat (engine bay connectors come to mind) or have diaphragms (central lock actuators come to mind).

Surprisingly, the connectors that reside under the carpet and route vacuum for the central locking are intact and soft.

So how do you get at the fuel door actuator?
 

I am curious what the best way is to get at the fuel door lock on an 85 300TDT?

It's behind the first aid kit door.

HIS POST IS ROGUE T PROTECTED!

There are a couple of diagrams on this forum that can give you a good idea on how to repair it.

I narrowed down my door leak to the vacuum pod in the front right passenger door lock. I have it pulled out and the little rubber on the top of the module ruptured and I couldn't find anything to replace it with.

So I bought a whole new one :( oh well.

You can glue the finger of a nitrile glove over it to seal the tear, but it doesn't last as long as the original diaphragm. Bosch sells replacement diaphragms. Someone will probably post where you can get them.

EDIT: Here's a pic of what I mean:
http://i204.photobucket.com/albums/b...ctuatorfix.jpg

Eh it's whatever at this point. I have a whole new one coming tomorrow anyway. I can hold on to the old one and use it in case another one breaks.

If someone posts a link to where there's a diaphragm I'll be returning my brand new one to phil!

diaphragm source anyone? Phil? I am certain that Phil can source the diaphragm repair kits -

I sealed one of mine with a "skab" (inner tube repair patch). It had a small hole in it. That was back in March I think. The locks still work great and the car will hold vacuum indefinitely.

While inside my driver rear door to work on non operative window, I noticed that the diaphragm had a tiny tear so I removed and very carefully applied some black "tool dip" formula to seal crack -should be interesting to see if I can pull vacuum after this repair. Actuator would vacuum in down position as it self sealed its crack but lost vacuum going up as diaphragm crack was exposed - I did find the guy on the MBCA site who makes the diaphragms and emailed him to see how much he charges for replacements -thanks!

Thanks, found it and also found the hose to the vacuum reservoir under the storage liner on the floor.

Fortunately the fuel door diaphragm held vacuum.

I noticed two hoses running from the pulse damper near the oil filter. Anyone know which two circuits those lead too?

85 300TDT

Has anyone tried this before?
 

I was thinking about leaking vacuum pipes the other day and I thought that applying that heat shrinking plastic that electricians use over electrical connectors might be a solution.

I'm talking about this sort of sleeving:-

http://www.radioshack.com/product/index.jsp?productId=2062662

Has anyone ever tried that before?

Good idea or bad idea?

How did you get the black plastic top off?
 

Wondering how you got the black plastic top off? I have the replacement bosch part (BO 3 340 522 025), but can't seem to yank the plastic off, as you've clearly done by the looks of the picture!

Anyone sell a replacement vacume connector package for w123s? Basically a kit with all new connectors for the vacume system. If not, someone should start. I would much rather buy a kit then have to piece it all together.

The clip itself pulls upward like a lock. Once it unclips you can split the clip off of the metal plunger.

It may take a little more pulling then you think it may so don't be afriad to pull it off.

Are these really worth repairing? Everytime I'm at a junkyard, I have the opportunity to pull like 40 of these. Some of them even hold vacuum :).

Seriously, they will cost you a few bucks and you can get them out with a 10mm socket and some snips for the vacuum line. I bring my mightyvac and test them on the spot.

It was worth repairing in my case since I don't have any junk yards near me with MBs. I'd have to drive at least an hour to get to the closest one.

That repair lasted about a year, but I ended up getting a new actuator. I think I'll order some replacement diaphragms from George Murphy if I need to fix a leak again.

I have pulled several at PNP, all have been good. price good too, $1.99.
so far, no vacuum leaks since I last posted. :)

ARMY asked in post #17 about using heat shrink tubing. I don`t believe it will work, too stiff.

that Plastic Dip for tool handles might work.

Best thing, is to just replace it with a new one. the old one`s made it for 15 to 20 yrs or so. or just Micky Mouse it together and hope for the best.

Charlie