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

Valve adjustment help

Thread Tools
 
Search this Thread
 
Rate Thread
 
Old Dec 31, 2011 | 06:06 PM
  #1  
dav3's Avatar
Thread Starter
Newbie
 
Joined: Nov 2011
Posts: 4
Likes: 0
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
Reply
Old Jan 16, 2012 | 12:23 PM
  #2  
StevieBenz's Avatar
Member
 
Joined: Aug 2009
Posts: 78
Likes: 0
From: NY baby
85 300D(the trusted), 97 E420(the ticketed)
Don't risk it, get it towed
Reply
Old Jan 18, 2012 | 12:07 PM
  #3  
Outre's Avatar
Member
 
Joined: Aug 2010
Posts: 92
Likes: 0
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.
Reply

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 


You have already rated this thread Rating: Thread Rating: 0 votes,  average.


All times are GMT -4. The time now is 10:17 PM.

story-0
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

Slideshow: Not every Mercedes design becomes timeless, some feel stuck in the era they came from.

By Verdad Gallardo | 2026-05-12 18:09:07


VIEW MORE
story-1
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

Slideshow: Yes, Mercedes built manual cars, and some of them are far more interesting than you'd expect.

By Verdad Gallardo | 2026-05-02 12:36:58


VIEW MORE
story-2
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren

Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.

By Verdad Gallardo | 2026-04-29 11:19:28


VIEW MORE
story-3
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

Slideshow: Before curves took over, Mercedes mastered the art of the straight line, and some of those shapes still look right today.

By Verdad Gallardo | 2026-04-25 12:05:49


VIEW MORE
story-4
Flawlessly Restored Mercedes 190E Evo II Heads to Auction

Slideshow: The 190E Evolution II shows how a homologation necessity became a six-figure collector icon.

By Verdad Gallardo | 2026-04-22 17:53:47


VIEW MORE
story-5
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

Slideshow: Mercedes is turning one of its core nameplates electric, and the details show just how serious this shift is.

By Verdad Gallardo | 2026-04-21 13:58:06


VIEW MORE
story-6
Mercedes EQS Gets A Major Update: Everything You Need to Know

Slideshow: Faster charging, longer range, and a controversial steer-by-wire system define the latest evolution of Mercedes-Benz EQS.

By Verdad Gallardo | 2026-04-15 10:35:34


VIEW MORE
story-7
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

Slideshow: These overlooked Mercedes-Benz models never got the spotlight, but they quietly delivered more than most remember.

By Verdad Gallardo | 2026-04-13 19:35:45


VIEW MORE
story-8
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

Slideshow: A well-used 1991 Mercedes-Benz 300D with more than one million miles is now looking for a new owner, and it still appears ready for more.

By Verdad Gallardo | 2026-04-10 10:05:15


VIEW MORE
story-9
10 Most Reliable Mercedes-Benz Models You Can Buy Used

Slideshow: From bulletproof sedans to surprisingly tough SUVs, these Mercedes models proved that the three-pointed star can go the distance.

By Verdad Gallardo | 2026-04-08 09:55:49


VIEW MORE