Valve adjust tools - PeachParts Mercedes-Benz Forum

mbzman · #1 12-06-2014, 11:07 AM

I need to adjust the valves on my '84 300D. I understand that you need wrenches that are bent in order to fit in to make adjustments. I found some on ebay below. What does everyone else use to make this job go smoothly?

Mercedes Diesel Valve Adjustment Wrenches | eBay

leathermang · #2 12-06-2014, 11:12 AM

This is very well discussed in the archives...
with pictures of both the store bought ones...
and homemade..
use my name to search .... in advanced search..
that ebay listing is only two of the potentially three you need...

Also... I would avoid that particular design....
the bends should be to where the two wrenches ' spoon ' .... SLIDE one against the other..... fit one on top of the other... AND have smooth surfaces...
thus you can use one hand .... and are placing the torque on the two nuts... one the cap and the other the locking one for the cap..
that means sometimes if needed... you can use your other hand to hold the third wrench below those two...

Diesel911 · #3 12-06-2014, 12:27 PM

If you are willing to remove the Fuel Injection Hard Lines and when your e-install the Hard Lined to leave the Nuts at the Injectors loose and crank the Engine till Fule comes out of the Hard Lines (to bleed the Air out) you can adjust the Valves with regular 14mm or 9/16" inch Wrenches if the Wrench Heads are 1/4" thick or less.

You may or may not need the 3rd Wench to hold the Valve Spring Retainer. You only need it if one of the Nuts is stuck.
There is alternative methods to hold the Valve Spring Retainer but for some reason in this last 2+ years some People have managed to crack off the top of the Valve Guide using alternative methods.

On eBay at one time used Valve Adjusting Wrenches used to show up on eBay but this last Year I have seen few of the complete stets.

uberwasser · #4 12-06-2014, 12:34 PM

I agree with what leathermang said about that style of wrench. I didn't like the large handles. The "proper" wrenches, as it were, are designed to slide over the other during the adjustment process so you don't have to remove the wrench from the nut as often. Much nicer. Proper wrenches shown below:

They are on the pricey side, but if you plan to keep your car a while and do valve adjustments on schedule, they pay for themselves quickly.

OM617YOTA · #5 12-06-2014, 12:44 PM

I made my own wrench. Custom bend on one, thinned so it wouldn't interfere with the nut above it, then hardened for strength. The other wrench has worked fine being unmodified. Less than half an hour time invested.

leathermang · #6 12-06-2014, 01:02 PM

Here is what has only been hinted at...
and what happened to me when I did my first valve adjustment about 2000.....

it was on my 81 wagon with five cylinder engine..... so I take all the stuff off to get to the valves..... and start from the front cylinder ... get to the last cylinder...which is pretty close to the firewall in terms of access....

and find one of the valve caps or locking nuts stuck.... it was on a weekend of course... as all bad things happen when the parts store you need is closed.... at that point I did not have a backup car...

so I had to put it all back together and drive it to get the third wrench from MB in Austin... then take it all apart to finish it up.... that is why I suggest getting all three proper wrenches....it will make each adjustment a lot faster and more pleasant...

In the archives is evidence that I made my own two upper wrenches... cheap using really strong Craftsman wrenches...I think 8 dollars each... and I tried making that lower wrench... but failed a couple of times... so I bought it ....