Ok...

First, let me show a picture of the part I need help with:


Next I have read this:
http://www.continentalimports.com/ser_ic20242.html

And I am a little confused.

Questions:
1) Do I understand that this item is basically a controlled leak?
2) The "source" for this item is is the input that is horizontal (NOT on top, but on the side) Correct?
3) I tried to test this item with my MityVac and, after plugging the TOP hose connection, it does NOT hold vac.
a) did I break anything trying to test this
b) is this how this item is tested.
c) HOW do I test this?

Thanks for helping with my laundry-list of questions.

Pete

What you got to do is test it while driving the car. You have to "tee" into the line going to the tranny, run a line into the cockpit of the car and put a gauge on the end in the car. You can actually use the mighty vac for your vacuum gauge. The pressure should fall off toward zero as you accelerate if I remember correctly. I should not go all the way to zero - down to around 5" IF I REMEMBER CORRECTLY. It has been awhile since I have had to mess with one of these. You remove the plastic round cover on top to get to the adjusting nut. It will make the car shift better if it falls off abruptly versus as a linear function based on what I have seen.

__________________
Jim

It can be done with the motor running and hood open as well, just don't let it hit redline while running the motor WOT.

Yes it is a controlled leak. Incorrect, the source is on top, the black line on the side is a vent line. When it doesn't hold vacuum it is already a bad sign that the valve isn't up to par. I doubt it. Test it with motor running. What is it at idle (should be 15-17"hg) what is it if you shoot the throttle to WOT real quick (should be near zero), what is it if you have the arm exactly 10mm from the stop (should be from 5-6.5"hg)? If you can adjust it within all of those specs then it is good, otherwise you may end up needing a new one to fix whatever shifting problem you are having.

__________________
Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

So you're saying I should hook up the vac. guage to the TOP and the vacuum pump should supply the SIDE?

I just want to make sure I test it right the first time!

Thanks,

Pete

I see how you are getting confused here. What we care about is what is sent to the tranny in those positions as we are trying to tune this valve for the transmission's shifting. So you unplug the (black) line going to the modulator and put the vacuum gauge there. The vacuum source is still traveling down those two Ys (one to EGR, one to damper which goes to the bleeder) and ending up on the top of the valve. The side doesn't matter at all, it is just there so dirt doesn't get in the system, nothing more.

__________________
Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

Boost & Team!

Thanks... seems my "white" bleeder hold vac. fine! Now that I know to test it from the top (duh!!)

And I did what you said about seeing if it drops... and it does. Not the exact numbers you mentioned... my numbers all seem HIGH... so I read this:

"""""The system works right when a high vacuum of 10-15 in. diminishes to zero at full throttle. It is most important to note that achieving the ideal vacuum depends most certainly on the proper volume of the vacuum source. Since the leak is of a given variable flow, the size of the source is critical. The most common problem I see is total lack of vacuum. This gives even, harsh shifts, slightly delayed in most variations.

Another common problem occurs after someone breaks the plastic source tee. During most of the ingenious repairs I have worked behind, the orifice was omitted. This leaves either a constant high vacuum or a variable vacuum that is skewed high. Either condition causes slipping or flaring conditions. This occurs when the vacuum supply is so great that the proportioned leak is small by comparison, resulting in vacuum that’s too high. """""

Here's my issue, when I pull the line that goes INTO the top of the bleeder (white thing) I get a reading of 21hg! -- now, based on the quote above, this is bad. (????) -- I'm guessing either my "green" can like thing is bad or something??? I have my "red" orifice in place (does it matter the direction of that little red things? (???)

So here's what I'm thinking... does that green "purge valve" knock down the vac level?

Any other input?

Thanks!

Pete

So how much vacuum does it have at idle? Adjust that so it is about 15", much lower (13" is the lowest I've had w/o) than that will give you a clunking as the tranny shifts into first gear.

To the best of my knowledge that green thing is a damper just put there so the valve doesn't get surges of vacuum, all it does is let the stuff through after it goes a path. 21"hg means you have a good vacuum pump, there is nothing wrong there. Remember that value isn't leaked it is straight from the vacuum pump, the value they speak of in the quote is the value going to the tranmission after the bleeder leaks off a certain amount.

__________________
Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

Ahhhhh!!! AFTER... got it!

Ok.

Back outside to the car now...

From what I can see... there is a leak with the EGR system that is causing a drop in vac. Sooo...

I'm going to go test the EGR first, RIGHT at the EGR, and then work my way up the line --- thermovalve -- and then to the switchover valve and the central plug...

I guess what I'm saying is... let me know if you know of any "issues" that I should know about...

I'm going to go out and tinker.

Odds are it is in the valves atop of the camshaft cover, they are known to leak in time. After all, under that cover are more rubber hoses which are 20+ years old.

__________________
Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

With all the bends and what-not in those rubber hoses on the valve cover......

I'm thinking about reading the thread about disabling the EGR...
I might just need a little shove to do it, this might be just that shove!

Remember disconnecting the vacuum source to the EGR only works if the valve is good, if it is bad the EGR will still leak exhaust gases through.

__________________
Jeff M.
Mercedes W123 DIY pages are now located here.
1983 / 1984 300D Sold
2000 CLK430 Cabriolet ~58k Sold
2005 Avalanche 4x4 ~66k

Ok,

We're at a steady 10-11hg @ the trans line. and it holds it there.

There are NO other leaks in the system (the egr line is plugged) -- Sooo... I found this:

"""""The system works right when a high vacuum of 10-15 in. diminishes to zero at full throttle. It is most important to note that achieving the ideal vacuum depends most certainly on the proper volume of the vacuum source. Since the leak is of a given variable flow, the size of the source is critical. The most common problem I see is total lack of vacuum. This gives even, harsh shifts, slightly delayed in most variations.
"""""
but you're saying 15-17 -- I'm thinking I going to adjust it up to 15 and see if things smooth out.

Thanks again,

Pete

Be sure to check the tsb's for your car at alldata.com.... Mercedes upped the recommend vacuum numbers for some cars around the early 80 's....

Ok, somebody is messing with me.

I pulled the little 'ivory' dome off of the bleeder valve. There is a brass type tit under there. about 3 mm from the tip of the tit looks to be a brass collar with a slit on each side.

There is NO nut under there. When I move the throttle this brass tit moves with it.

What am I missing?