once warm:

throttle / vac (in.Hg)

0 / 15

1/8 / 10-12

1/4 / 7-9

1/2 / 6-7

3/4 / 5

full / 3

shifting is not very predictable in the upper ranges.

there may be a small exhaust leak pre-turbo.

jt20 - Let's make certain you have the correct vacuum diagram...
 

Jt20,
Let's make sure you are using the right 1985 W123 diagram... for Federal car:
http://www.peterschmidtransmission.com/vacuum/1977_1985/617_95/1984_1985.jpg
or for California car:
http://www.peterschmidtransmission.com/vacuum/1977_1985/617_95/1985_cal.jpg
for there is a considerable difference... and I hope you do NOT have a California car!!

As to having the precise color/size of orifice shown for your car, I'm inclined to not worry too much and IF you purchase any of these plastic orifices, concentrate on obtaining the small sizes: Here are the orifice color/sizes/pn(s) I have posted in POST #1 of this now very long THREAD: http://www.peachparts.com/shopforum/diesel-discussion/158216-its-critical-how-you-set-your-transmissions-vacuum-system-your-diesel-mbz.html

Color: I.D. P/N:
Yellow……2.0 mm..……..1162760929
Red……….1.1 mm….…….1162761029
Blue………1.0 mm…………1162761129
Brown……0.9 mm…..……1162761429
White……0.8 mm…………1162761229
Green……0.7 mm…………1162761329
Black.....0.6 mm......... ___?_____ **
?????.....0.5 mm......... ___?_____ **

** IF anyone knows these P/N(s) and the color of the 0.5mm orifice, pass it along to me and I will go back and revise my POST#1!!
Regards,

oh boy. Here we go.

I DO have a Cali. spec engine. Information about the .5 mm orifice is unobtainable with my set of abilities. I certainly have two orifices of the same color (cleari-ish, NOT black! = .6mm) which have an ID slightly greater than the other (orange = .5mm) orifice. I can only assume they are correct since no parts dealer or local dealership was of any help.

If these are the right sizes, then my vac system is doing well.

Those figures are fine. If the vehicle exhibits any sign of flaring, a small adjustment to the VCV can be made to reduce them a bit.

Does the vehicle have the blue flying saucer.......or does the line to the transmission go directly from the VCV?

blue UFO - saucer / vac amplifier

That's rather interesting. The amplifier is normally used to modulate the effects of the VCV..........tending to keep a level of 10" or so for most of the operation.......this is my observation on the 603's.

Your setup shows vacuum numbers that are quite typical of a straight VCV setup.

The bottom line is whether it flares or not. If not, you're good to go.

thats the original issue. I don't completely understand what flaring is. My rpms don't shoot up b/w shifts... but they certainly do not go down much. (except 1st-2nd)

from the Brotherton article:

The most important modification came with the 1985 model and is continued on all subsequent ones. It involved the addition of a vacuum amplifier to the system (see Fig. 7). The amplifier takes a large vacuum supply, the proportioning vacuum signal and a boost signal and creates the final signal to the transmission. This device did two things. First, it incorporated the input of boost to further tailor the load control of the modulator vacuum signal. The vacuum at the modulator now starts high - 12-17 in. - and is reduced to about five inches through straight throttle movement. As boost builds, the vacuum is further reduced to zero only at full boost.

You'll know flaring when you have it. The engine runs away in a "false neutral" during the shift and you'll immediately lift your right foot.

Sometimes, the engine will have a "soft" shift that takes 1/2 second or so......you can make an adjustment to firm it up and cause less wear on the clutches if you wish.

My main concern is wear. And the term is definitely 'soft'. Some shifts are 1/2 second to a full second. Is this a worn out trans. or poor regulation?

The question on the '85 is whether you can adjust it to bias the curve downward. Take a look on the underside of the amplifier. There should be a black port with a cover on it. Below the cover is a small plastic hex.........4mm, IIRC. Turn this hex fully clockwise and make the test again...........noting the vacuum levels at the various pedal positions.

I've got the adjustments on mine down to "as good as it gets" until I get the new springs in. I still have a 3-4 flare but I can avoid it totally if I make that shift manually. Around town, I just leave it in S.

... jt20 - I too have a Calif. 300SD [W126] under my care...
 

Jt20,
I too have a 1985 Calif. 300SD [W126] car that I watch over... and so once again I did a quick comparison between the 1985 Fed & Calif. models... and the Calif. model has 10 additional numbered components on it's diagram. The largest differences are that on the Calif. models there is a "CAT" in the car's exhaust system and a "controller"/computer!

It's no wonder there is another THREAD on our FORUM that was been dedicated to the matter of converting the Calif. models to the same as a Federal car! I must say my In-Law's '85 Calif 300SD certainly shifts a great deal better than my '80 240D... but then diagnosing a problem in the vacuum system will no doubt be far more complicated!! AS I see it there were so few of these cars with this far more complicated Tranny-Shifter system on them... thus you are not likely to ever see much definitive being written about these cars/systems

Regards,

BC - I have an adjustment on the VCV (driver's side) and the VacAmp. Is the cap you are referring to perhaps red-ish and has an MB logo in the center? Should I adjust one at a time - which one first?

Sam - I pray for you and that Cali. in so many ways.

Thanks again for your help fellas.

jt20... you are wise to stay with Brian on these newer cars...
 

jt20,

I have played around with these VCVs enough to know there are at least two different styles... and I think the newer one that you most likely have the adjustment is more readily recognizable... whereas the design on the older ones is not at all obvious. Tell us more about what you have... a digital photo would be nice... with the dome/cover removed! Did you removed it from the car... and is that how you found the adjuster feature?

No need to pray for me... for need is one hell of a motivator... and when I become fully responsible for our 85' W126 Cali car, I will be learing a lot about these extra components and maybe POST my ideas. Q - Doesn't your car have all the California car's components as shown on the "Cali"-diagram??

However in the mean time on your other matter, by all means you should stay with what advice Brian is giving you on these additional components that are only on the newer models... for I have NOT yet had much experience with them.... I just mainly know what I see when comparing the diagrams... and when I see the numerous differences that the 1985 California models have, I'm convinced that I will think long and hard and probably do everything I can to convert our 1985 CA W126 model to essentiall be like a 1985 Federal model... and IF/WHEN I do this, then I will no doubt learn a lot about the various components are and be in a better position to assess whether the California models' tranny-shifter vacuum control systems are worth saving.

My gut tells me the 1985 Federal models shift just as well as Calif models... so IF I can avoid public flogging and/or capital punishment here in "GREEN" "Calee"fornia, I'll probably go "FEDERAL" [not "POSTAL"] and sell off the extra California parts on Craigs LIST or Ebay to supplement my retirement income!!!

Regards,

Adjusted the VacAmp to fully CW.

Downshifting became a bit too harsh and vacuum was reaching 0 inHg close to 3/4 throttle. Afterward, I backed it off about 10*-15* CCW on the VacAmp.

I think its safe to say all fine tuning can be made on the '85 as you suggested, Brian. I am very satisfied with the results.

In glorious addition to the shifting benefits, my brake pedal finally stiffened up -- now that the VacAmp is consuming less. The whole time I thought I was prepping for a new Brake Booster.

Sam - when its warm out I will post pics of the components involved.

thanks again.