Where does the red hose that is vissible on pics goes and what does it do?

 

Where does the red hose that is visible on pics goes and what does it do?

When you look at a Vacuum Diagram it is the colors of the plastic tubing that matter and all of the Plastic Tubes have either short pieces of rubber vacuum line or go into 3 way or 4 way rubber connectors.

The Black hose with the red stripe is just a short piece connecting the Brown Plastic Tubing and I believe brown manes it goes to the Vacuum Shutoff; it should have a blue stripe on it but that may be on the underside of the line.

 

Rubber hose from MB has 6 lines molded into the rubber, and (usually) a color stripe. The spacing of the lines and color of stripe designate the inner diameter of each. I am not sure of the exact specs, sorry.

The red-striped hose you see in the picture connects the brown vacuum line from the ignition switch to the shut-off switch on the back of the injection pump.


BTW, that method of looking at the gap will get you in the ballpark, but you really do need to have a Mityvac to check your readings, and fine tune.

 

can I put this guide on my wiki?

 

Horray for the wiki. The wiki rocks dieselbenz!

 

I suppose, but remember that this is only the rough way of doing it. Technically, you're supposed to loosen the nut, put a donut of a certain thickness (1mm IIRC) onto the peg, put the arm up to the peg (stopped by the donut), then tighten the nut back down.

But like I said, the best way is to use a Mityvac so that you know the values you have what you are changing it to.

 

How do you test to see if there is enough vacuum first before making adjustments? I unplugged the line going into the top of the VCV and squeezed the pump once, and it read and pretty much held at 15inHG w/a very gradual slow reduction in reduction. Is that too much? Should there be any vacuum reduction at all? Am I testing it properly?

So many questions; so little time.

Novice@Best

 

Its better to adjust it on the engine with it running.

Also, there are three different types of VCV. One can't be adjusted.

 

Well, I tested it while it was running; however, can you take that VCV off while its running? Is that even possible?

Secondly, I should have been more clear. I am talking about the VCV that is pictured by GREG300CD.

Novice@Best

 

my vcv does not have a lock nut and after adj it to eliminate flaring it reverts back to high volume (15) after sitting over night
also it does not have a cap over the adj nut ....does that matter
is there a solution
where can one be purchased
thanks
Kevin Codraro

 

It's possible to remove the screws and take it off of the IP while the engine is running, but it is controlled by the linkage, so you won't have accurate functionality.

Test how much vacuum is being sent to the modulator on the transmission.

You need the screw to hold the adjustment. If it's missing, you need to get another.

BTW, my VCV was so far out of whack that this really seemed to be the best option for me. I had it in my hands and I could tell what was happening when I turned the flattened shaft. For minor tuning, you should probably leave it attached to the IP and check the readings with the MityVac.

 

Tried this..but the VCV on my car does not adjust. There is no nut. Just a sleeve with somewhat of a "crush" sleeve on the thread. No matter how hard you try...no go.

So...I'm still trying to diagnose shift issues. Modulator does not leak. Vac at pump is 22" hg. Vac at VCV is 15" hg.

Now it seems that the shifts are late/hard. In order to get it to shift from 2-3 and 3-4 you need to lift your foot off the accelrator for a second and it will shift.

Quirky.

Any suggestions are welcome.

EDIT: Solved by removing the EGR and thermo valve lines. Shifts MUCH better.

 

I adjusted mine.

The way to do it is using a gauge, not a hand pump.

Vac at VCV should be ~15hg and the pump at ~23hg. If not it may be failing.

- Before starting the car see where is the full throttle position in the VCV lever. (it should be at the stop pin, if it wasn't there is some rod adj. u need to do)
- Disconnect the rod that is attached to the lever, careful with braking the plastic pin, its old and brittle.
with the engine running move the VCV lever to the position where it was at full throttle (at the stop pin or 1mm from the stop pin at the most) in this position the vacuum should be 0hg.
- Move the lever slowly and see how it proportionally decreases vacuum as it gets closer to the stop pin.

If you need to adjust it, take the VCV off the fuel pump unscrewing the allen screws. Keep it connected to the vacuum source (top) but remove the vacuum leak connection (side).

Remove the little housing or even better remove the flat head screws and take the whole lid off and do what is mention earlier in this post to get the vacuum to be at 0hg when the throttle is fully open.

- install it back, connect the leak line that goes inside the car, and the rod.

-stretch your back because it may be hurting at this point.

-test drive.

-celebrate with german beer or belgium beer only.

-hug a tree.

-take a deep breath

 

I too had shifting nightmares to the point that I was the only one in the family who could drive the car, and that was going to be over a cliff if I couldn't get it sorted out soon. Then I read a procedure somewhere about adjusting the vcv. At idle, with the linkage disconnected, should have 15 hg. Now with the cover off, locknut looose, get a 10mm guage...I used a nut taped together with a thin washer for an exact 10mm, and hold inbetween the stop and the lever. At this point the vacuum should be beween 5.5 and 6.5 . Mine wasn't close so I turned until I had exactly 6 then tightened the locknut. Shifted like an absolutely normal modern day car after that. No issues whatsoever left to sort out. No flaring, stacking, no oddities at all. Previous to this I had changed tranny fluid/filter, adjusted shifter linkage, adjusted valves, removed vacuum mess from top of valve cover, adjusted bowdan cable, installed the K1 kit, and turned out the alda close to max. I was preparing to check modulator pressure (which I suppose I should have done first), but now have no reason to bother. DO this if you are having shifting issues.

 

...Now with the cover off, locknut looose, get a 10mm guage...I used a nut taped together with a thin washer for an exact 10mm, and hold inbetween the stop and the lever. At this point the vacuum should be beween 5.5 and 6.5....

Which "stopper" do you refer to? Is it 10mm from the WOT stopper or idle stopper?



This?:

 

You can use a small disc 2 cm (0.8 inch) and a hole in the middle, I made one of wood.

 

I adjusted mine about 1/8th turn, hard shifting went away. You can actually just suck on the vacuum tube on the top to know when it opens relative to the throttle position. It should stay closed right about to the position pictured above with the 2cm spacer, then open. What an awesome, easy DIY.
Thanks Benzworld Elite!

 

Or this:

 

Tested and adjusted my VCV today. Smth I've been wanting to do and should've done a long time ago had I known that it was so easy. Thank you all for your input.

Quick question. I find that my VCV with the linkage in the default position wants to be at about 14g in order to bleed completely at full throttle. The pump exerts about 22g. When VCV output is at 15g exactly, the pointer stops at about 1 - 1.5 at full open. I left it at14g for now to road test the shifting. I only drove the car around the block a couple of times and the shifts are a bit "bumpy" but not hard nor flaring. Downshifts felt fine.

Someone mentioned that the throttle linkage may need to be adjusted. Mine currently stops about 1mm from the stop. Is that normal or should it touch the stopper?

The biggest test will be when the transmission gets really hot in summer traffic. The downshifting used to be pretty clunky then. I can't wait to fully test the performance now.

 

5.29.21

This is doable but you really should do a hot ATF drain and replacement including the torque converter and filter then warm fully and connect a pressure gauge to the correct test port on the tranny and adjust it to the correct modulated pressure and then use a vacuum gauge connected to the VCV and make your final adjustments , a half inch of change will make a BIG difference .

There are several different types of VCV's , some have a 7MM lock nut, others have only the two sided 8MM thing, some require you to unscrew two #1 Phillips screws to remove the cover to access the adjuster, others have a short or tall rounded plastic bump shaped cover... .

In either case you hold the VCV's lever on the far side of it and give the adjuster nut a tiny tweak as you watch the vacuum gauge ~

I just finished doing this to my '82 20D's tranny, I've had several M-B trained mechanics fiddle with it and none took the time to do it properly ~ any used machine will have different tolerances so just "setting it by the book" isn't enough .

Higher modulator pressure (test this with the engine running and the vacuum line disconnected) should be set to the book, each tranny has a slightly different pressure, more pressure (turn the 'T' clockwise) makes the shifts firmer and later,

Lower vacuum (adjusted at the VCV) higher pressure makes for later shifts, but if you go too high it gets bad, same with lower pressure, my 240D wanted about 7" of vacuum at idle , then it began to properly start off from a dead stop in first gear instead of jerkily down shifting as soon as you touch the throttle .

German machines always are more adjustable than other countries , if you're patient and delicate you can really fine tune it well .

Even S.W.M.B.O. noticed the improvement .

 

300Dman to the rescue!!! Yes, You are correct, Brown=Shutoff. Where is... Stretch, Funola, D.Morrison, Mach4, DeliveryValve... and, about 10 others from about 06-16. I learned a lot from them and you too 300Dman!

 

It depends on how it drives ~ if you like the way it shifts then yes, it's O.K. .

Mine clanked from second gear into first at every dead stop take off and in time this ripped the drive splines out of one of the planetary gear sets at the worst possible time with my Foster kids and old lady in the car, in rush hour traffic, I worried we'd be killed .

I'm finally satisfied with it now and will hopefully soon be able to get some time to attach vacuum and pressure gauges, jot down and post up the results .

 

My w123 Always had a hard shift and a clunk when slowing down to a stop, The clunk only happened when it upshifted to 2nd, then had to stop before it upshifted to 3rd. As I recall firm shifts are good, and flared shifts are not. But take that with a grain of salt. Firm shifts are good on the clutch packs, but hard on the flex disks. Flares, while easy on the flex disks, wear out the clutch packs.