Hi again, Sam. No, that link is not to my car. Mine was an eBay purchase, but not that one!

I have been pulling lines and testing them with my MightVac, and testing at the vacuum line that tees off the orifice in the main line from the pump shows a leak from the get-go. I capped the lines to the locks, euro lights, and even the shutoff valve, one at a time and all at once, and the leak is still there. Capping the line that runs down to the IP (the one I references in an earlier reply that runs vertically down along in front of the oil filter resevoir in my pic) slows the leak considerably, for what that's worth. I have capped the door lock and light adjustment lines and will drive the car after a bit to see if it makes any difference.

I'll try to post some pics in sequential order from the main line junction on out for folks' edification... look for those later tonight. I'll see if I can't get a better pic of the IP as well. Thanks again!

Oh yes, my VIN: WDB12313012218553

Thanks, my friend!

Chris

__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)

One more question -- If I'm reading the peterschmidt diagram right, I don't see that the line running to the automatic transmission should run through the switchover valve at all (nor the VCV, for that matter). Is this right? Mine is running from what is marked port "III" on the switchover valve. (BTW, my switchover valve has a broken paddle which will need replaced). Ports I and II lead to what must be the VCV on my car, but I wonder if they were inadvertently swapped at some point. On my car, the line from "62" (orifice in the main vacuum line from the pump) runs down to what I'm calling the VCV near the back, outer driver's side of the IP. It runs into a "Y", one end of which enters the rear port VCV and the other of which feeds port II of the switchover valve. That would provide constant vacuum to port II. As I said, there are 2 ports on the VCV. The frontmost port runs up to port I on the switchover valve.

Strange, strange, strange. The port (III) that the diagrams indicates should feed the VCV in fact feeds the transmission on my car. In the diagram, port II is not occupied, it seems. Port I seems to be fed a supply of constant vacuum from the Y that is fed by orifices 63 & 63.

The plot thickens... hope I have not confused matters further!!!

Chris

__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)

Chris,
Disregarding the fact that we believe your 1980 normally aspirated 300D to be a "Euro" model we would be using the diagram at: http://www.peterschmid.com/vacuum/1980/617_912.jpg... but IF in fact yours is a "Euro" model we need to use our diagrams carefully. The fact that all 3 of the vacuum connection on the single 3/2 switchover valve are in use, this is probably due to it being a "Euro" model.

Yes, I'm convinced that your VCV is on the outside of your "MRSF" type IP and it has two vacuum connections on the top with one having a restricted orifice below the " Y " connector. If like so many other MBZ components, I'll bet your VCV has a p/n and I'd love to have it. Judging from your photos and the shop manual I have, I'm guessing your VCV mechanically connects to your IP on the backside of the VCV. Sooner or later I'm thinking you will want to remove your VCV to clean it if for no other reason... and to see if its vacuum bleed-off action is still smooth over an increasing IP/throttle load. I'm sure the "Euro" models worked on the sam principal as the U.S. delivered cars, we just have to figure out how things should go from looking what diagrams we do have. I think your 1980 Euro is hooked up similarly to our later models but yours [thank goodness] does not have the extra ordeal of an EGR!

Keep finding and plugging those leaks... and sending those "pics",

Chis,
I tried looking up the VIN you gave above... but it does not seem to work at the Russian site I tried!

Have you already obtained an in-depth readout on your VIN?

Regards,

Hi Sam -- maybe I copied & pasted it wrong; yes, I ran it on the Russian site and got a full page of info. Def. a Euro 300D.

Here's the rub: I fiddled with the vacuum system all day yesterday and got the transmission line to see the vacuum it should be, and yes, it drops as rpm increases. So I crawled under and turned the transmission modulator in one turn and shifts are now much better. 1-2 is very crisp, and 2-3 and 3-4 have much less flare. I may try another 1/2 turn in time, but I am now wondering what controls shift rpm on my car. I have no Bowden cable, and it seems to be shifting quite HIGH now, rather than too early.

I'm getting closer, though!

Chris

__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)

PS -- just ran my vin at http://www.mbclub.ru/mb/vin/view.html and it worked fine.

__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)

... to the best shift you can Chris and your 1-to-2 shift is still too hard for your liking, then I would recommend a dashpot for ~$5.00 as a way to soften this problem. On the cars delivered in the U.S. they started adding the dashpot on the 1981 models... so I tried them on our two 1980 models and this worked out quite well for us.
Regards,

Sam -- thanks for the tip. I think I'll try the dashpot, as 1-2 is a little on the firm side. Any idea how I can change my shift points? Thanks again!

__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)

Chris,
First thing, thanks for the off-FORUM suggestion on runing your VIN on the Russian WebSite. I ran a couple of ours and it came back saying that we have leather seat covers... NOT !

Back to the engine/tranny vacuum control for your new/old 300D Euro... which IF your VIN info is correct, probably is a 1979 model... agree?

If I remember correctly you haven't yet resolved all of your vacuum leaks and/or component failures... what about your 3/2 [aka switchover valve] problem. My point is that I would first go through the engine/tranny vacuum control system line and components... clean the line(s) internally and each component, replace any that are clearly miss or not functioning properly, then take a look at the vacuum being delivered to the tranny's vacuum modulator while driving the car. This vacuum signature needs to be just under 20...~15 lets say and smoothly reduces to ~zero at full throttle.

IF we don't have something close to this as a signature, then we need to definitely remove and clean that unusual VCV on the side of your not-so-usual "MRSF" injection pump on your car. I told you that we would have to go very much "tongue-and-cheek" with your "Euro" model ! I have recently disected an old VCV from one of our cars and feel much more confident that I can help you deal with yours IF it is not properly doing its job to create and send the proper variable vacuum signal to your tranny.

Finally, to my way of thinking IF what you mean by "shift points" is at what speed and/or RPM it shifts, then this is the modulator on the tranny... but again we have to get our ducks in order and make sure the rest of the engine/tranny vacuum control system is working properly first... including a check to see just how large any restricted orifice is in the vacuum tack-off at the main vacuum pump -to- brake booster line! This should be less than 1 mm. dia. If you have a caliper, you can gauge the hold with different size needles until you find one that is "snug" and then check its dia. with the caliper!
Regards,

Thanks again, Sam. So the modulator on the transmission controls shift quality AND timing? (i.e. it will allow elimination of "flare" and firm up the shifts AND the rpm at which the transmission shifts?) My shift quality is much better since I turned the modulator in one turn, but she now shifts later (i.e. runs too high in the rpm range before shifting to 3rd and 4th gears).

I did test the vacuum bring supplied to the transmission, and it does indeed decrease with rpm. I will check again to see if that is still the case. I will also order a dashpot to add to the transmission vacuum line. Thanks!

__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)

[QUOTE=cscmc1;1476074]Thanks again, Sam.
So the modulator on the transmission controls shift quality AND timing? (i.e. it will allow elimination of "flare" and firm up the shifts AND the rpm at which the transmission shifts?) My shift quality is much better since I turned the modulator in one turn, but she now shifts later (i.e. runs too high in the rpm range before shifting to 3rd and 4th gears).
I did test the vacuum being supplied to the transmission, and it does indeed decrease with rpm. I will check again to see if that is still the case. I will also order a dashpot to add to the transmission vacuum line. /QUOTE]

Chris... We got to have some #(s)... for instance I'd like to know the readings when the system is reasonably "tight" and there are no known origin or unknown leaks... so close or clamp any of these off first... then read:
(a) the vacuum directly off of a "T" coming off the main Pmp-to-Brake booster line? and while you are reading this at idle, bring the engine speed up to ~2K and see how much it rises?,
(b) in the engine compartment off of a "T" installed in the line that goes down to the tranny modulator... read this at idle, and
(c) then read the vac again when you slightly advance the throttle enough to trip your 3/2 switchover valve... there can be a slight decrease... give me this reading and whether and what it dips to,
(d) then put enough vacuum line on this same "T" off your modulator line and place the hand pump under one of the windshield wiper blades where you can see it while driving... and observe while you drive around a bit. You are looking to see that under different speeds/loads... you are looking to see IF it "SMOOTHLY" transitions to a much lower [almost zero] reading... tell us how smoothly the vac drops and what reading it bottoms out at when you ptpttm [put the pedal to the metal] at say 30 mph. Don't burn rubber and get a ticket!
Regards

When it rains it pours! Just got back from a little jaunt to the parts place and the grocery store to pick up some flowers for the wifey, and observed the following:

First, the transmission started shifting at the proper (or at least much more reasonable) points on the way home. Interesting, and I haven't altered a thing in the last 24 hours.

Second, I have a nasty leak at the IP all of a sudden. About a drip per second. Need to sort that out pronto!

When I got home, I was curious, so I went to get my MightyVac and take a quck reading at the line to the transmission. I took at at the point where the line leaves the switchover valve. Initially it read about 16 pounds at idle, and decreased to about 5 as rpms headed toward redline. My switchover vale has a broken finger, so I suspect it's not working quite right yet. I am ordering one, among several other things, from Fastlane this week.

I stood up long enough to stretch my back, and by the time I ducked back under the hood, vacuum at idle was down to about 10 pounds. Go figure.

More leaks to track down -- both vacuum AND fuel now! Huzzah!

__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)

Check out my photo at:
http://ericandkat.com/mercedes/W123VacDoorLockDiag.JPG
I would also purchase a yard of that small dia. MBZ vac. line and replace any 3-way, 4-way fittings that are too dry and hard to use the electric ties on for tightening as show in the Pic above!
Regards,

I was just getting caught up on this thread and read with interest this item about incorrect vacuum to the tranny causing differential wear over time. I purchased a mityvac and now that the weather is getting better and I have my benz out of the garage, I need to get my hard 1-2 shift problem solved. I replaced a few cracked vacuum hoses last fall and closed off the EGR system, which improved the 2-3 shift and softened the 1-2 shift.

But now to the point of my post: I have this rumbling that I feel when slowing down to an idle, and have assumed that I need to look at the univeral joint. But maybe it is the differential. If my problem is the differential, is it something that can "bust" suddenly and leave me standed, maybe doing further damage? I have never worked on a rear end. How involved is it to inspect the differential gear and replace it?

__________________
85 300D 75K Anthracite Grey 0-60 in 13 seconds **For Sale**
84 300D 333K Black (The Velveteen Rabbit) 0-60 in 14 seconds
00 Toyota Sienna 208K (Sold)
15 Subaru Outback 43K
11 Subaru Outback 67K
98 Ford Taurus 100K (Gertie - Was Grandma's - drove it to church and shopping - really) Daughter's car now.
30 Model A Ford 2 Door Sedan (Sold) 0-60 in . . . Never reached 60

RML - First off I confuse parts terms and confuse differential & universal all the time ! Take a look in your PM.

Yes, I think your "rumbling" probably is in the drive-line... and is in order of likelihood either:
(1) so many miles and wear-and-tear on your car that the differential[rear-end] is getting loose! A good way to diagnose this is to drain the oil and put in the heavier 140 weight gear oil. If this quiets things down some, you know you have found the problem... and you might want to keep the heay lubricant... realizing it will knock a little off your fuel mileage!,
(2) one or both of the two flex couplings in your drive line,
(3) one of your drive CV axles,
(4) the center support bearing and/or rubber mounting for this bearing, AND/OR
(5) also check the rubber support(s) that the differential hangs from or is supported by.
Regards,