'81 300D - Linkage Adjustment and Vac Tools Recommendation - PeachParts Mercedes-Benz Forum

paulem · #1 03-10-2006, 03:02 PM

1981 300D (NA).

First, I've got to adjust the linkage. It idles super high, shifts really high, and looking at the accelorator pedal, the pedal doesn't make contact with the kickdown switch. I replaced the engine with a junk yard special, so I know that the linkages would need to be adjusted anyway. I've been searching but haven't found a good write up on how to do this? The Haynes is really vague, and my MB shop manuals are lost in a box somewhere. Any advice or links on this would be greatly appreciated.

Second, vacuum issues. I know this is also contributing to my faulty shifts. I've re-routed the lines so the 3/2 valves are out of the picture, I've got it all hooked up correctly. I need to test the pump and the whole system. I know I need a gauge and a mighty-vac, yeah? Anything else? Anybody recommend a particular gauge? Where's a good source for these things?

Thanks,
Eric

MattBelliveau · #2 03-10-2006, 03:53 PM

The mity-vac actually has a guage on it...

dieseldiehard · #3 03-10-2006, 04:10 PM

I prefer using a gauge larger than the one on a MityVac for troubleshooting esp watching for a dropping vacuum level, such as diagnosing the severity of a leak. You should be able to find one for about $15.
see: http://www.thetoolwarehouse.net/shop/KD-2521.html
They also sell a MityVac 4000 silver for about $45

dieseldiehard · #4 03-10-2006, 04:14 PM

Quote:

Originally Posted by paulem

1981 300D (NA).

First, I've got to adjust the linkage. It idles super high, shifts really high, and looking at the accelorator pedal, the pedal doesn't make contact with the kickdown switch. I replaced the engine with a junk yard special, so I know that the linkages would need to be adjusted anyway. I've been searching but haven't found a good write up on how to do this? The Haynes is really vague, and my MB shop manuals are lost in a box somewhere. Any advice or links on this would be greatly appreciated.

Second, vacuum issues. I know this is also contributing to my faulty shifts. I've re-routed the lines so the 3/2 valves are out of the picture, I've got it all hooked up correctly. I need to test the pump and the whole system. I know I need a gauge and a mighty-vac, yeah? Anything else? Anybody recommend a particular gauge? Where's a good source for these things?

Thanks,
Eric

When you rerouted lines did you remove the small controlled vacuum device that is used in line in the vac line around the trans line form the IP modulator to the vac source? I am referring to a thin double male "thingie" the body is colored green, yellow, brown (and maybe other colors)???

Its Very important that you revert that to the system if in fact it has been removed.

dannym · #5 03-10-2006, 04:25 PM

Quote:

Originally Posted by paulem

1981 300D (NA).

First, I've got to adjust the linkage. It idles super high, shifts really high, and looking at the accelorator pedal, the pedal doesn't make contact with the kickdown switch. I replaced the engine with a junk yard special, so I know that the linkages would need to be adjusted anyway. I've been searching but haven't found a good write up on how to do this? The Haynes is really vague, and my MB shop manuals are lost in a box somewhere. Any advice or links on this would be greatly appreciated.

Second, vacuum issues. I know this is also contributing to my faulty shifts. I've re-routed the lines so the 3/2 valves are out of the picture, I've got it all hooked up correctly. I need to test the pump and the whole system. I know I need a gauge and a mighty-vac, yeah? Anything else? Anybody recommend a particular gauge? Where's a good source for these things?

Thanks,
Eric

You'll find information on adjusting throttle control linkages here:

http://skinnerbox.steaky.org/Service/W123/Index/617T/30AcclCtrlSys.htm

Danny

dieseldiehard · #6 03-10-2006, 04:34 PM

I suggest not adjusting anything until you verify the presence of the correct vac controlled device (pin hole actually) that I mentioned previously, because if you adjust the length of the linkages or the controlled leak on the IP, to affect shifts, you are losing a good reference point, and it may be a real bear to get everything back to proper setup if the vac devices are missing you are going to do nothing but make a real job for somebody!

paulem · #7 03-10-2006, 06:52 PM

Dieseldiehard - are you referring to the dashpot? I didn't remove it . . . I have line running from the first tee in the mailine that goes to a three way. The three way is connected on one end to the dashpot, which connects to the VCV on top of the IP. The other part of the threeway goes to the trans.

I am pretty sure this is how it is supposed to be, right? The vent valve on the side of the IP goes to a black line that vents it the passenger compartment. My understanding is that as the speed increases, the vent opens more and the vacuum is routed through the vent instead of to the trans . . . right?

I just looked at my linkages, I'm afraid I'm missing a piece. I'm gonna go snap a pic and upload it . . .

Eric

Diesel Giant · #8 03-10-2006, 06:54 PM

Maybe this will help.

http://dieselgiant.com/mercedesvacuumtroubleshooting.htm

paulem · #9 03-10-2006, 07:25 PM

OK, here are some images to illustrate my confusion!

1. This shows how my vac lines are now set up. The 3/2 valves are no longer connected. I have tees in the lines for the CC and the door locks (trying to isolate the issue).

2. This shows the area of the linkage where I am concerned that I've lost something. This is illustrated in both the second and third images.

3. Just curious, what are these ball sockets for? I always assumed it was for cruise control, but isn't that controlled by the cable from the actuator?

Dieselgiant - thanks for the link. I've studied and studied that page! ITs great info that you've put together there.