Well I traced a vacuum leak to the seat lock (I have a coupe) now I need to find the others.

I think that the ACC servo(s) is bad because I never get air to my feet. It will switch between the defrost and the center vents (only if I push defrost first).

I went to the engine compartment and pulled the green line and hooked it up to a mighty vac. I was able to get a vacuum, but it wouldn't hold.

Does anybody know how many servos there are behind the dash, and where to look for them? I pulled the glove compartment and hooked the Mighty Vac to the servo that's clearly visable, and it held.

I'm Service Manual CD handicapped because I sold the CD along with my old coupe, and I haven't bought a new one yet.

Thanks,

Craig

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1994 E420, Pearl Black/Black. 2.82 rear diff., AMG front spoiler, painted lower half. SOLD

1972 & 1974 BMW 2002tii's.

I just looked behind the ACC unit and I saw 5 connections numbered 1 thru 5 from drivers to passengers side.

I tested the #4 (red) and it held vacuum. It went to a controller behind the glove box on the left.

I tested #5 (green) and it didn't hold vacuum. Green goes to a controler below the passengers windsheild.

Does anyone know what #'s 1 thru 5 operate? Looks like I need at least a #4.

TIA,

Craig

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1994 E420, Pearl Black/Black. 2.82 rear diff., AMG front spoiler, painted lower half. SOLD

1972 & 1974 BMW 2002tii's.

Not 100% sure on the 300CD, but I think legroom flap is #2 (red/yellow?) Default is closed position.

__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

I only have tech. info on the 1977 300D W123 climate control and can't help with color codes. The floor outlet vacuum actuator is found by removing the lower left instrument panel trim cover on my car.

I had to do a very serious diagnostic once to fix my climate control and found the best way to check it was by doing each individual component with my Mity Vac tool (solenoids, actuators, one-way valves, vacuum lines, connectors, etc.). I replaced one vacuum actuator and a couple of one-way vacuum valves (located inline with the vacuum lines). Then I found a short (2") piece of vacuum line that had a leak and then found a plastic "Y" connector that leaked (fixed with a bit of epoxy).

Also I have had broken parts on the vacuum actuator. The plastic piston/rod (connected to the diaphram) that extends out of the vacuum actuator for the center defrost vent has a flat metal rod connected to it with a small rivot that inturn was connected to the control flap for the defrost. The plastic piston/rod was broken where the metal rod connects with the rivot and I fixed it with a bit of epoxy.
So, you need to look for both vacuum leaks and broken parts.
Good Luck!!
Tom

__________________
America: Land of the Free!

1977 300D: 300,000+ miles

American Honda: Factory Trained Technician & Honor Grad.
Formerly:
Shop Foreman;
Technical Advisor to Am. Honda;
Supervisor of Maintenance largest tree care co. in US for offices in Tex.

Am I correct to assume that all the vacuum controls (#'s 1-5) should hold a vacuum?

I'll take off both instrument panel covers and look at what's under there.

TIA,

Craig

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1994 E420, Pearl Black/Black. 2.82 rear diff., AMG front spoiler, painted lower half. SOLD

1972 & 1974 BMW 2002tii's.

I have just finished helping a friend pull the dash to replace a leaking evaporator coil. In the process, we found five vacuum
actuators buried in and around the heating/cooling unit---four of the actuators would not hold vacuum (they should all hold vacuum) with problems that ranged from a tear to very small holes in the diaphragms. Since we had everything apart , replacing actuators was not that difficult. The bad news is that two or three of these actuators appear to be situated so that dash removal is the only way to get to them.

Ken

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K. Weimer
300SD (1)
300D (5) [Plus 1 parts]
300SEL 4.5 (2)
280SE (4)
280 (2)
250 (1)
250SE (1)
240D (7) [Plus 1 parts]
220D (11) [Plus 3 parts]
200D (2) [Plus 1 parts]
180c (with sunroof)

1995 Nissan UD1800 rollback
"If I can't fix it, it don't get fixed"

I was afraid of that. I know that I have at least 1 (#5, green) that needs to be replaced. I haven't checked the others but I think #2 (footwell air flap, I think) might also be bad.

Do you know how much they cost?

Since I need to replace the dash, that would be the time to do it. I need a supplier for the dash other than the dealer ($650).

Thanks,

Craig

__________________
1994 E420, Pearl Black/Black. 2.82 rear diff., AMG front spoiler, painted lower half. SOLD

1972 & 1974 BMW 2002tii's.

Vacuum actuators are about $35 each if you can locate a "non-dealer" supplier.

__________________
K. Weimer
300SD (1)
300D (5) [Plus 1 parts]
300SEL 4.5 (2)
280SE (4)
280 (2)
250 (1)
250SE (1)
240D (7) [Plus 1 parts]
220D (11) [Plus 3 parts]
200D (2) [Plus 1 parts]
180c (with sunroof)

1995 Nissan UD1800 rollback
"If I can't fix it, it don't get fixed"

Thanks. I usually buy most of my stuff from Performance Products because they are near me. I'll check with them.

If not, I'm sure that Fastlane has them.

Thanks again,

Craig

__________________
1994 E420, Pearl Black/Black. 2.82 rear diff., AMG front spoiler, painted lower half. SOLD

1972 & 1974 BMW 2002tii's.

When I fixed my vacuum problems 5 years ago, the actuators cost $38 each from M-B. No telling how much now. After replacing the actuator I came across some info about a rebuild kit (diaphragm with the piston/rod and a sealing ring - as I recall - that cost 1/3 the price of the actuator), but I did not follow-up to see if the repair kit was actually available. A search for the kit would be worthwhile since you need to replace so many and good info for other members that need to fix their's.

As I recall, only the actuator for the main air door requires pulling the top portion of the dash on the 300D. Hopefully that actuator is still good. Also, a very slight leak or reduction in vacuum over a period of time for the actuators is allowable according to M-B.

The problem in removing the hard to reach actuators are the retaining clips. They can be hard to reach and remove/install without breaking the small plastic pin they fit onto. Best to remove the small bracket the actuator is mounted to if possible - as I recall, some of the bracket mounting screws were behind the actuator itself and could not be reached without first removing the actuator. Perhaps some other members have a favorite technique for removing the actuators.

When you buy the new actuators make sure the metal connecting rod moves freely without binding. A hard moving/biding connecting rod can cause the plastic piston/rod connected to the diaphragm to break or possible displace the diaphragm so it becomes unseated or tears. The new official M-B actuator I bought from the dealership had a very hard to move connecting rod caused by the connecting rivet being too tight (the same problem with the original actuator). I removed the connecting rivet and reinstalled it allowing for more freedom of movement.

You can by a dash cover for about $110-$125 that will look almost like the original. I do not know if the sponsors of this forum sell them, but check with them first. If they do not sell the dash cover, then check with Performance Products.

Good luck!
Tom

__________________
America: Land of the Free!

1977 300D: 300,000+ miles

American Honda: Factory Trained Technician & Honor Grad.
Formerly:
Shop Foreman;
Technical Advisor to Am. Honda;
Supervisor of Maintenance largest tree care co. in US for offices in Tex.