Mercedes-Benz W123 Odometer, How To Repair Odometer How To Repair Odometer How To Repair

As many of you might notice, the Odometer of the Mercedes-Benz W123 will break down after some years. Most of the times the digits will become “stuck”, the cilinder won’t turn anymore. Here’s a step-by-step-guide to fix this problem:

1. Find the panel located under the steering wheel and dashboard. Slots and screws ensure that this distinctive panel is securely in place. This feature also offers additional assurance that you have reached the correct area. Begin by loosening as well as removing each screw. Be careful to store the loose items for installing the panel after this repair is completed.

2. Reach forward and push cables until the gauge protrudes outwards. Look for the cable that presents oil levels. It should appear to stand out with a unique metallic color similar to gold or bronze tones. Also locate the current connection to the speedometer. The line will appear to be thicker than most selections.

3. Ensure all remaining cables and selections are disconnected. These choices may vary by model but should cover basic functions such as lighting. Take extra precaution to avoid possible damage or injury by testing each one before removal.

4. Find the equipment that houses the entire grouping of gauges. The outer shell should move after carefully applying pressure. If that fails, pull outwards with a larger amount of force.

5. The panel is now completely removed from the dashboard and free of obstructions. Check for any type of damage or external issues on the entire piece.

6. Look for the area that houses the clock, found on the left side if the area is placed face down. For further identification, the raised piece features two tiers that stand up above four circular open spaces. Inspect the clock to find screws that must be removed. Take each one out and place with other screws that have been removed during the process. Keep these labeled with their location. Take out the entire clock and place with other items that are already labeled.

7. Move on to the centrally located speedometer. Take out the screws and remove this feature as well. Look over the rest of the panel. Any remaining screws as well as pieces should be detached at this point in the process.

8. Carefully pull up the speedometer without damaging or interfering with any other places on the panel. Look for any protruding parts that could become stuck. Begin to inspect all gears on the speedometer. They should be in good condition with no excessive wear. Materials should be free from obstructions or other damage. Warped gears are often a reason for improperly functioning odometers. Items closest to the actual counter are a common cause for issues. If the gears must be replaced, ensure that the right size and shape is chosen before going forward.

9. Finish taking apart the speedometer. Take precautions to keep each piece safe while not in use. If a gear just needs repair instead of replacement, clean it thoroughly first. Slick or wet gears will need to be thoroughly dried. Use a metal appliance such as a drill bit or use sandpaper to create the necessary friction.

10. After all issues are addressed, start reassembling the dashboard. A simple way of doing this is to go backwards in the exact order of removal. Correct labeling and marking of parts during the process should make this an easy to accomplish step.

Repairing a odometer on the Mercedes-Benz W123 takes dedication and the right amount of knowledge to properly complete. Following these steps will make the job less difficult for even a novice to automotive maintenance.

Mercedes W123 Engine Specifications

Mercedes W123 Diesel Engine 300TD 3.0 litre motor

Mercedes W123 Diesel Engine 300TD 3.0 litre motor

The Mercedes W123 was built with different engines, both petrol and diesel. I will now give an overview of all the different engines that were supplied in the W123:


The fourcilinder carburator engine M115 with 2.0 and 2.3 litre engine size were taken over from the previous Mercedes-model W115 almost without changing anything about it. The basic contruction of these engine however is even older, it comes from the M121 engine out of the 190SL.

During the periode in which this engine was used, alot of changes were incorporated in the design which made these engine the most durable and reliable of there time, or even for all time as some would say! :) As these engines were built for darubality and reliability they lacked in some other aspects: they were/are relatively thirsty and didn’t have the highest performance in terms of power, even for that time.

But the 200 basic-model did more than enough for most people, and even today it is an engine which can easily keep up with modern traffic. The 230 model gives even more driver’s comfort because of the higher torque which makes it a very enjoyable engine even for today’s standards.

The engine together with the rest of the Mercedes W123 gives a driving pleasure combined with a legendary almost indestructability, which is what appeals to most W123-drivers nowadays. Besides run in camshafts caused by too little (or none at all) maintenance and age problems concerning the carburator there are almost no common problems known for these engines, which is quite a performance considering their age!

The M115 came in the following types:

  • M115.938, (type 200) straight-4 four cilinder 2.0 litre four stroke engine, one single overhead camshaft (SOHC) with a double chain, 1998cc, 87.0 x 83.6 mm, 158 Nm at 3000 rpm, 94 hp at 4800 rpm.
  • M115.954, (type 230) straight-4 four cilinder 2.3 litre four stroke engine, one single overhead camshaft (SOHC) with a double chain, 2307cc,  93.75 x 83.6 mm, 186 Nm at 3000 rpm, 109 hp at 4800 rpm.

The M115.938 was supplied only in the W123 saloon, the M115.954 was supplied also in the coupe (W123 230C) and in the T-series (230T).


The M123 engine is a six cilinder 2.5 litre four stroke engine with one single overhead camshaft (SOHC) with a single chain and came in only one type, it was however updated during it’s lifetime:

  • M123.920 (from september 1981 123.921) (type 250)
    86.0 x 72.45 mm
    192 Nm at 3500 rpm (from september 1979: 200 Nm at 3500 rpm)
    129 hp at 5500 rpm (from september 1979: 140 hp at 5500 rpm)


The M102 engine is a four cilinder,  four stroke engine with one single overhead camshaft (SOHC) with a single chain and came in two types, a 2.0 litre and a 2.3 litre type:

  • M102.920 (type 200), straight-4 four cilinder 2.0 litre four stroke engine, one single overhead camshaft (SOHC) with a single chain, 1997cc, 89.0 x 80.25 mm, 170 Nm at 3000 rpm, 109 hp at 5200 rpm.
  • M102.980 (type 230E, E stands for Einspritzung=injection), straight-4 four cilinder 2.3 litre four stroke engine, one single overhead camshaft (SOHC) with a single chain, 2299cc, 95.5 x 80.25 mm, 205 Nm at 3500 rpm, 136 hp at 5100 rpm.


The M110 engine is a six cilinder, 2.8 litre four stroke engine with double overhead camshafts (DOHC) with a double chain and came in two types, a carburator and an injection-type:

  • M110.923 (type 280), a six cilinder, 2.8 litre four stroke engine with double overhead camshafts (DOHC) with a double chain and a carburator, 2746cc, 86.0 x 78.8 mm, 223 Nm at 4000 rpm, 156 hp at 5500 rpm.
  • M110.981 (type 280E, E stands for Einspritzung=injection), a six cilinder, 2.8 litre four stroke engine with double overhead camshafts (DOHC) with a double chain and injection, 2746cc, 86.0 x 78.8 mm, 234 Nm at 4500 rpm (from april 1978: 240 Nm at 4500 rpm) , 177 hp at 5800 rpm (from april 1978: 185 hp at 5800 rpm).

How to replace the handbrake/parkingbrake on a Mercedes-W123?

Hello everybody!


In response to a question of a reader (stephenm) today I will explain how to fix the handbrake / replace the brake pads of the handbrake / parkingbrake of a Mercedes W123.

If the handbrake or parkingbraje doesn’t work anymore it’s most common because of 2 reasons: the special handbrake-pads are worn or everything is rusted. (The cable can also be broken but that’s easy to determin by removing the wheel and then have somebody apply the parkingbrake while you check whether the cable moves).

Regarding the 2 most common failures (pads worn out or rusted) please follow the steps below:

First use this document, it’s in German from the official Mercedes-Benz dealership manual:

Now I’ll walk you through it, if anything won’t come loose spray it with WD-40 and let it soak for 10 minutes before trying again:

-order a new handbrake pad-set including fasteners and including new springs(!)

-remove the wheel

-remove the 2 bolts to remove the caliper

-remove the caliper

-use a rubber hammer to hit the brake disc in order to remove it

-remove the springs by using a pointy pair of plyers or use the special tool (nr 112 589 09 61 00, I can tell you how to make it yourself, if you´re interested let me know!)

-Now remove the old springs and old pads (make a picture before you remove everything so you can see how to place the new ones

-mount the new springs and pads

-put everything back together :)

Now test to see if the handbrake is working, stand by the wheel and have someone else apply the parkingbrake.

Your handbrake should be working fine now!

Let me know how it went!

How To…Replace Brake Pads on a Mercedes Benz-W123

Today I just saved myself between 100and 250 by learning how to replace the brakepads on my Mercedes-Benz W123 myself! I’m so proud of myself hahaha!

Ofcourse it took me quite a bit longer than it would take a “real” mechanic, but hey for a first timer I’d say 3 hours for both front brakepads is not bad!

Now that I know how to do it I bet I can do it alot faster, like say in one hour. Here are my step-by-step instructions on how to replace the brake pads of your W123 yourself:

  • Before jacking the car up: steer a bit in the direction of the wheel you are going to remove so the wheel sticks out of the fender, this will make your life easier later on when replacing the brake pads.
  • Also before jacking up the car:  first loosen the bolts of the wheel a bit. It will go easier with the weigth of the car still resting on the weel. But loosen them only a bit! You will need a 17mm wrench to loosen the wheel bolts of a Mercedes W123.
  • Now jack the car up and remove the bolts and the wheel.
  • Lay the wheel down underneath the car for safety and put the car on an extra jack or stand for safety reasons also. You don’t want your probably 25+ year old jack or your 25+ year old rusty jack points (holes) collapsing with your head underneath!
  • Now with the car resting safely on 2 stands and the wheel removed: take a seat next to where the wheel used to be and start inspecting. You will see the brake disc and on it the brake caliper which contains the brake pads.
  • Now notice the state of the brake disc. Check for grooves in the surface and near the edges. Turn the disc around and see if it rotates easily and there’s nothing scratching the surface of the rotor while turning it.
  • Check the thickness of the brake disc. The brake disc or brake rotor of a Mercedes W123 should have a minimum thickness of 10.6mm front and 8.3mm on the rear. New Mercedes brake discs or brake rotors are 12.6 mm thick on the front and 10mm on the rear. If the discs are worn down replace them as well. If the rotors are still OK then stick to the original plan and replace the brake pads only, lucky you :)
  • Now look into the caliper to check the thickness of the brake pads. New brake pads for the 2 front wheels of a Mercedes W123 have a thickness of 17,5mm (Rear 14,5mm). The minimum thickness is about 3mm when the contact points are worn so the nice brake light on your dashboard will light up to inform you it’s time to replace your brake pads! In your case this is probably what happened or you wouldn’t be reading this I guess :) Most modern brake pads also give a squeeking sound when they are almost worn and need replacement.
  • You will see 2 pins holding in place a small metal spring plate. Use a small screwdriver or pin and a hammer to remove the 2 pins. BE CAREFUL: The small spring metal plate may jump out!
  • Put a big screwdriver between the brakepad and the disc to create a little space (don’t damage the disc!) and use a pair of pliers to remove the brake pad. Do this on both sides of the disc. (If you hadn’t noticed by now, Surprise: there are 2 brake pads per wheel! One on each side of the brake disc).
  • If you have made enough space it will also be easy to put the new pads in. Don’t make too much space though, just enough to put the new pads in! If you press too much you will press out the brake fluid from the engine compartment. That’s also why you should never add brake fluid when using old brake pads, because of the wear of the brake pads the brake luid level will lower, this is normal and no sign of leakage. It should always remain above the minimum indication ofcourse! After you have replaced (all) brakepads the brake fluid indicator should be on maximum.
  • Repeat at each wheel, don’t forget to tighten the bolts real well with the wheel on the ground is easier, otherwise you will use your strength to turn the wheel instead of tightening the bolt :) Now remember to start breaking slowly to “wear in” your new brakepads. You will not have full “braking power” the first few miles! Also don’t forget to check the brake fluid level.
  • That’s all folks! You’ve just saved yourself around 100 to 200!

Well my dear reader, how did it go? Did you find this Howto useful? Do you miss anything in these instructions?

W123 Buyer’s Guide–18 Things To Check When Buying A Mercedes W123

First and foremost: if you don’t know much about cars, take someone with you who does. Or even better, have the car checked out by a professional mechanic to be sure you’re not buying a lemon!

Don't buy a lemon instead of a Mercedes W123! 

Here are some tips and advices especially for the W123, if you find anything it doesn’t mean that you shouldn’t buy this car but it does mean that it’s going to cost you some extra to fix it…

  1. Feel if the engine is warm, if so: why did the owner pre-heat the engine before your arrival?
  2. Check the engine: is it dry, also on the sides?
  3. Check underneath the Mercedes, is there oil on the floor underneath it or hanging on the bottom of the car? Also check the gearbox for oil leakage.
  4. Start the car and listen, do you hear anything strange? Is the W123 engine running nice and smoothly? Also look at the smoke coming out of the exhaust, it’s normal to have some smoke coming out at start, but only at start! After a few seconds there should be no more smoke coming out of the exhaust (except when it’s very cold). White smoke could mean water in the engine (head gasket?), black smoke could mean the engine’s burning oil.
  5. Press the accelerator / pedal and keep an eye on the oil-meter. It should be on 3! If the meter drops while pressing the accelerator walk away immediately!
  6. Take the oil filler cap and check for whitish mayonnaise like sludge, if it’s there it could be the head gasket.
  7. Check the area around the hinges of the bonnet, these are known places for rust buildup.
  8. Check underneat all the mats for wetness and rust.
  9. Check the jack points (holes) for rust, a known place for a W123 to rust.
  10. Check in the trunk for wetness and rust: in the corners under the shelf and underneath the spare wheel
  11. Diesel only: take the oil filler cap and put it loosly on the empty space where it’s supposed to be tightened. Now see what happens. The oil filler cap can move a bit and “dance” slightly, but if it’s blown off completely that means the crankcase pressure is too high!
  12. Take the Mercedes for a drive. (You can take the W123 off the “handbrake” by pulling the lever on the left of the dashboard). Notice how the engine is doing on various speeds. Are there no sudden shakes or movements?
  13. Try shifting through all the gears while driving, is this going smoothly?
  14. Check the clutch in a manual driven (stick) W123 by driving in second gear and pressing the brake with your left foot while accelerating with your right foot. It should be slowing down and “choke” the engine. If it does: the clutch’s fine. If the engine is not slowing down but accelerates it could mean the clutch has to be replaced.
  15. Check the tolerance on the steering wheel, it’s normal to have a little tolerance but if it’s too much it can be costly to repair.
  16. Check the condition of the tyres, not just the profile but check for dryness and an even wear on the front tyres.
  17. Check the front fenders, are they aligned with the bonnet? Are all the seams the same width, also around the doors? If the seams are unevenly wide it could mean that the car has had severe damage or damage that was badly repaired.
  18. Check inside the car: the condition of the lining and chairs. Also check the dashboard lights and electronics like the AC, sunroof and windows. Basically check every option on the car: is it working?

Now you have a reasonable indication of the condition of the car. But don’t blame me if you still buy a lemon! You’re there, I’m not! Most important thing is: if you don’t know cars, bring somebody who does. Even if he’s never driven a Mercedes W123 in his life, he may still be able to check the condition of the engine and gearbox, the most expensive parts of the car!

If you’ve used this list, please leave a message! And also if you can give more advice to add to this list that would be most welcome!

Did you ever buy a lemon?

W123 Specifications


The Mercedes Benz W123 was produced in the period 1976 – 1985. It is a higher middle class car and the successor of the W114-W115 model. It was succeeded by the W124 model.

The Mercedes W123 is one of the most succesful Mercedes-Benz models ever, in every imaginable way. Mercedes sold over 2,7 million cars of the W123 model making it the most successful models ever. But also in terms of durability the W123 is one of the most succesfull if not THE most successful car ever. It still can be seen driving around all over the world, being driven by a man (or woman) with a big smile on his or her face!

The W123 was made in several 3 variations, most common are the 4-door Saloon or Limousine/Sedan, the “T” or Touring/Wagon/Estate/Station and the 2-door Coupe. Below some specifications for each of the models:

General information:
Petrol Engines: 2,0 – 2,8 Liter (94 – 185 BHP)
Diesel Engines: 2,0 – 3 Liter (55 – 125 BHP)
Weigth: 2954 – 3704 pounds (1340 – 1680 kg)

Wheelbase: 110 inch (2,795 mm)
Length: 186 inch (4,724 mm) (euro bumpers)
Width: 70.2 inch (1,784 mm)
Height: 56.5 inch (1,435 mm)
Weight: 240D: 3047 pounds (1385 kg)
Built models: Petrol: 200, 230, 230E, 250, 280, 280E. Diesel: 200D, 220D, 240D, 300D and 300D Turbo.

Wheelbase: 110 inch (2,795 mm)
Length: 186 inch (4,724 mm) (euro bumpers)
Width: 70.3 inch (1,786 mm)
Height: 57,9 inch (1,470 mm)
Weight: 300TD: 3318 pounds (1505 kg)
Built models: Petrol: 200T, 230T, 230TE, 250T, 280TE. Diesel: 240TD, 300TD and 300TD Turbo

Wheelbase: 106.7 inch (2,710 mm)
Length: 182.6 inch (4,640 mm) (euro bumpers)
Width: 70.3 inch (1,786 mm)
Height: 54.9 inch (1,395 mm)
Weight: : 230CE: 2954 pounds (1340 kg)
Built models: Petrol: 230C, 230CE, 280C, 280CE. Diesel: 300CD and 300CD Turbo


About the author

Welcome to!

First and foremost I’d like to tell you guys (and girls!) that I’m no professional car-mechanic! Just your ordinary guy who loves to drive his Mercedes-Benz W123 and loves (DIY) Do It Yourself, to work on my Mercedes that is!

Since I bought my W123 I’ve been crazy about it and I was very interested in the technique of this car. Because I always want to know “how everything works” I wanted to know how a mechanic would do something relatively easy, regular maintenance like renewing the brake pads or changing the oil filter and I started thinking: if this guy can do it, I must be able to do it myself! I’m not dumber than he is! And neither are you, we just have to know “how to” do it!

So please enjoy the website and if you have any questions, comments, tips & advice please let me know!

Yours truly,