E-Class (W123) 1976-1986: 240D, 280E, 300D, 300TD, 300CD

Valve adjustment help

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Old Dec 31, 2011 | 06:06 PM
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dav3's Avatar
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300d
Valve adjustment help

Today I attempted to do a DUI valve adjustment on a 1983 300d. On the first valve I could not get it adjusted, gave up, put cover back on and now it is over tightened on first valve. I have contacted a local mb mechanic to finish the job. My question is can I drive it to his shop or to have it towed? is there any chance of the top nut coming off if driven?
Thanks in advance
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Old Jan 16, 2012 | 12:23 PM
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StevieBenz's Avatar
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From: NY baby
85 300D(the trusted), 97 E420(the ticketed)
Don't risk it, get it towed
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Old Jan 18, 2012 | 12:07 PM
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83, 300D Federal
I agree that it is better not to risk driving it to the Mechanic.
With these old Cars it is better to be a member of one of the Auto Clubs that allows X amout of free Towing for x amount of miles.
I have AAA and you can be come a member over the internet. The cheapest one for one persont was $45 jper year but you will need to check that.

A lot of people have done their own Valve adjustments but having the special bent Wrenches is a big help.
Also the Wrench set comes with a 3rd wrench that holds the upper Valve Spring Retainer when one of the Nuts is stuck. However, there is other ways to keep the Spring Retainer from moving so the 3rd wrench is not mandantory.

The next easiest way to do the Valve adjustmen is to remove the Fuel Injection Hard (Steel Tubing) lines that attach to the Fuel Injection Pump and Injectors.
This allows access with regular combination Wrenches; with the exception the one of the Wrenches may need to have the thickness of the Wrench Head thinned.

The next proble is after you re-install the Fuel Injection Hard Lines you need to leave the ones on the Injectors loose until while cranking the Engine you see a steady amount of Fuel comong out of them.
That Bleeds the Air out of the Tubings. Air trapped in the Tubing can keep you from starting the Car right away.

The last issue is how to turn the Engine.
You can use a remote starter button connected to the Starter Solenoid and + Battery terminal.
You can use the Mercedes recommended method of using a 27mm Socket on the end of the Crank Shaft to turn it.
Some have used the Nut on the Power Steering Pump to rotate the Engine. I have done this and it required me to adjust the Power Steering Belt tighter than normal to rotate the Engine. I had to remember to return the Power Steering Belt back to the normal tension.
It is easier to rotate the Engine by hand with the Glow Plugs out.

The Engine should be rotated Clockwise as viewed at the front end of the Crankshaft.
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