M103 Fixing List / FAQ / Links / Tips

[ps2cho]

Problem: Shocks worn / Shock Mount cracked Fix: This job is actually quite easy with the correct method and does not take long either. Start by loosing bolts on wheels, jack the car up and support it on quality stands. Remove wheel and place new jack under the lower control arm. MAKE SURE to SUPPORT the weight of the car ON THIS JACK. You want the spring to not move when you release the strut. Once the lower control arm is supported, unbolt the bolt on the top of the mount in engine bay. Push shock down (should do if worn) and now remove mount. PS: If your shock is worn a bit, you may not need to jack car up. You can do it all with wheels on ground. Just unbolt top mount bolt and push shock down. Now replace. If shock is needed to be replaced continue. Undo the three bolts holding the shock in place. The upper mount will need a 19mm wrench to hold other the side from spinning. The bottom two are easy. Remove strut and support brake disk and associated items from hanging on the brake lines. Prop it up with a box or something.... Installation is reverse. My tip is to push the shock through the mount and secure using an old bolt to hold it in place. Now do the upper bolt FIRST because it holds it in the right place. Should be straight forward. Safety is always #1 with anything suspension related, but as long as the lower control arm is supported, you should have no problems. Pics:

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[ps2cho]

Problem: Want to upgrade Audio Head Unit
Fix: I made a tutorial at the link below. This will only apply to early w124's without factory amp. This will save you a ton of time.

http://www.peachparts.com/shopforum/...6&postcount=25

[ps2cho]

What Engine oil should I be using??

For the M103 and M104 engine, the correct oil (dino type/diesel grade) should be used.
These oils have additives necessary such as zinc additive to prevent premature wear that would otherwise occur with a "regular" gas engine oil.

The major choices are:
Shell Rotella-T 15-40
Mobile1 Delvac 1300 15-40
Chevron Delo 400 15-40
If you are in a colder part of the country, you may want to run something lighter such as 5-40, but these work for me in Socal weather. Just make sure to pick a dino-type oil to make a long lasting happy Mercedes-Benz engine.

General engine oil info

Originally Posted by Corey over at Peachparts

->Don't mix oil grades (weights), the formulations, chemistries, additive packages are complex and the results you get may defy simple logic

->Fully synthetic (API group IV and V) oils perform better in extreme cold, in terms of easier starts, presumably due to better viscosity profiles at those temperatures

->At the least, use a diesel-rated (API C*) oil in a diesel engine. One of the biggest factors is the oil's ability to suspend soot, which is a necessity with diesel engines.

->Lubricant technology has made great strides in the past 15-30 years, and our original owner's manuals do not reflect that in their recommendations

[epowers777]

I will throw in there amsoil Go to that link and search. The tranny oil is within MB specs (the true numbers not dextron junk) Also engine oil is great and has long change intervals (cheaper long run) and u can sent oils in to get tested which I highly recommend.

Ps i am not an amsoil rep just a happy customer.

[ps2cho]

Problem: Windows do not work.
Fix: Start by checking Fuse G/H (or associated fuse) to make sure its not blown. If its A-OK now swap window buttons to make sure the button is not dead. If you have checked both of those, its probably safe to say the motor is dead by now. If it fell out of the regulator it should be obvious as it will move but be all out of alignment.

Pull the door panel off. Link on previous page for this. Now get a 12V/18V battery or car start charger and apply voltage to black + green wires that go to the window motor. If the motor moves great! If it does not, motor is dead for sure.

If motor does NOT move using voltage:
Get a new motor + regulator. The fronts are two separate units, the rear's are combined because it uses a pulley and wire. You cannot (well nothings impossible...) or it will be very difficult to buy separate and fit together. The following pictures show rear. Front is easier to get the motor out, but more tricky to get the window to sit correctly on regulator as it has many slide rails.
Start by undoing all 5/6 10mm bolts + nuts until the motor is free. Now push it towards the rear of the car so the bottom metal tab comes unlocked. Now push up for top tab to be released (don't be weak or afraid...its gotta come out shown in 2nd picture).

Now the motor + regulator should be free, but able to swing back and forth because its still attached to the window. Now on the guide, there will be a little black plastic part that holds the white rectangle in place so it doesn't fall out of the rail. Press the tab either side and pop it out. Now just slide the motor left/right and remove using the orientation in 3rd picture. That's it! Installation is reverse.







Motor works with battery, but I can't seem to get it to move via buttons!!?? OR Fuse keeps blowing soon as I turn key

A wire is most likely frayed in the door and is shorting out. Follow the tough black heatshrinked wire through the door until you find where it is torn. You can also check resistance from one end of the wire to where it meets in the center console. It meets at the button so you'll have to open up the plastic housing UNDER the button to access the wire. There will be (4) total and it will match the ones from the door obviously so that will be your check to know you have the right place.



All fixed and functional! I recommend properly heat-shrinking it over electrical tape as it will be a better long term solution. I just did it so I could quickly isolate and rule off that section. It happened to be where it was shorting so I did not need to dig further thankfully

[pifcat2]

The motors are replaceable (AFAIK for early models). I had a rear wire type from a sedan with a bad motor but with good wire and pulley and another from a wagon with no wire and broken window mounts. There are differences but the motors are interchangeable. The orientation on the motor on the regulator is different and the housings were metal vs. plastic with different screw thread types. The plate must be removed to expose the serrated or tri-armed wire spool. The screws are T-star type. The wire ends have ends that fit into the spool and wrap around on opposite sides. Once wound tight, you have to force the spool into the motor housing and get the plate that secures it on and screwed. It is tight. Make sure the orientation of the window bracket it correct, apply 12V on the motor to move it back and forth to check. Grease it and your assembly is ready to install.

[ps2cho]

Problem: Replacing drivers/passengers door lock cylinder.
Fix: MAKE SURE you can get the key to turn 60 degrees towards the rear of the car otherwise you are gonna have to drill it out. At the slightest hint the key is getting hard to put in, I recommend replacing the lock. I paid $40 for the new lock + key VIN matched at the dealership. This is not an expensive item.

Open the door and remove the small black circle cover that exposes a 3mm hex key. Start by undoing it counterclockwise 4 rotations (roughly...I did 4.5 to be safe). Now insert key and turn 60 degrees towards rear of car and push sideways toward rear of car. It should push aside without much force needed. Now simply tweak it and turn key slightly and pull out. It was a lot easier than I thought it would have been.

I recommend at this point removing the door handle completely and claying, polishing and waxing the paint inside the handle as its very hard to reach any other time. Also consider spraying your handle if its faded as this time too.

Installation is reverse. I found it easy to use the 3mm hex key to push the door lock towards you so the handle can fit behind it. You'll understand what I mean when you look inside. Its a brass colored metal flat that goes back+forth to unlock the door.

[ps2cho]

Problem: Why should I use a Bosch Oil filter? Does it even matter?

Fix: The reason why you should only EVER use Bosch oil filters on both the M103 and M104 engine is because most other cheap filters do not have, or have a fail-to-function spring-loaded check valve. This check valve ensures that oil from the filter does not drain down into the sump when the engine is off. The next benefit is that this check valve keeps oil inside the filter so that upon startup, there is a readily available amount of oil to begin instant lubrication. This is paramount for engine longevity.

So stop getting your cheap walmart/FRAM filters and get Bosch. It only costs a couple bucks more.