Mercedes Crankshaft Pulley / Harmonic Balancer DIY

This tutorial covers common harmonic balancer/crankshaft pulley problems and instructions on replacing them. This is a common problem with Mercedes-Benz equipped with the M112 and M112 engines. These two engines are installed on many Mercedes-Benz models manufactured between 1995 and 2005, including E-Class, C-Class, S-Class, and ML-Class. This is a common problem on Mercedes-Benz models ending with 240, 320, 430, and 500.

What is a Harmonic Balancer?

A harmonic balancer (a vibration damper or crank pulley) is the main pulley that drives the accessory belts on a Mercedes-Benz engine. It is connected directly to the crankshaft. The harmonic balancer has two metal components. The outer ring drives the serpentine belt and the center of the crank pulley. Both are metal and are joined by a rubber damper.

Its main purpose is to spin the serpentine belt. It also helps to absorb some of the engine vibrations by using rubber elements between the crank pulley outer ring and the center of the pulley.

Due to heat, the age of the vehicle, and normal wear, the rubber fails, causing excessive crank pulley vibrations and even catastrophic failure in some cases. It needs to be replaced. The good news is that the engine doesn’t need to be removed, and a DIYer can replace it.

Because the crankshaft pulley drives the serpentine belt and all the accessories, including the water pump, alternator, power steering, and a/c compressor, if it fails, you won’t be able to drive your vehicle.

Let’s watch it in action.

Symptoms of a bad harmonic balancer: 

This is a list of common symptoms of a bad harmonic balancer on a Mercedes-Benz.

• Crankshaft pulley excessive movement
• Pulley outer ring separating from the center
• Crack on the harmonic balancer pulley rubber
• Noise from engine
• Crankshaft pulley wobbles

If you notice any of these symptoms, replacing the harmonic balancer before it completely fails is better.

Mercedes Harmonic Balancer Removal Tool

To remove Mercedes-Benz harmonic balancer, you will need a Mercedes crankshaft pulley tool to hold the crankshaft in place and stop it from rotating. The tool can be purchased online on sites such as Amazon and eBay. Mercedes harmonic balancer tool costs between $50 and $80.

Instructions on how to replace harmonic balancer

The good news is that you don’t need to drop the subframe or remove the engine to replace the harmonic balancer. It can be removed with the engine in place.

Step 1: Open hood

Pull the hood release on the lower left corner of the dashboard. Go to the front of the car and pull on the hood handle. Next, lift and secure the hood in the upright position.

Step 2: Remove the radiator fan

On most Mercedes-Benz models, you must remove the radiator fan and shroud. This is required as there isn’t enough room for you to hold the harmonic balancer in place and, at the same time, use a socket to remove the bolt.

The radiator fan can be easily removed. There are clips on the side of the fan that you need to press and pull out the fan. Before you pull the radiator fan upwards, unplug the electrical connector.

It must also be removed if you have a pre-2000 Mercedes-Benz equipped with a viscous fan. To remove the fan, you will need Mercedes-Benz viscous fan tool..

Here is a video on how to replace the viscous fan.

Step 3: Remove the serpentine belt

Remove the serpentine belt. You must place a socket on the belt tensioner and pull it until you can slide the belt out.

Step 4: Loosen the crank pulley bolt

You will need to use Mercedes harmonic balancer tool to hold the crankshaft pulley in place as you loosen up the 27 mm bolt.

You will use the harmonic balancer tool to keep the crankshaft from turning. Next, use a 27 mm socket on the bolt to loosen it up. You will need to use a breaker bar such as Neiko 00206A 1/2 Inch Drive Premium Breaker Bar, 24″ Length | Cr-V Steel to get this bolt loose. Add a cheater pipe to your breaker bar if you can’t get it loose.

You will apply over 200 Nm of force to the bolt, which requires considerable energy.

Step 5: Install the new harmonic balancer

Pull the old crankshaft pulley out. Now it is time to install the new harmonic balancer. You will need to hold the crank pulley using the harmonic balancer tool. Next, loosen the bolt with a breaker bar and a cheater pipe/extension.

The last step is to reinstall the serpentine belt.

Harmonic Balancer Bolt

This central bolt secures the vibration damper to the engine crankshaft.

• Bolt: M16 x 1.5 x 77 mm long
• MB part number is 112 031 00 71
• Socket Size: 27 mm typical

Torque Specifications

• Clockwise direction – tighten
• Torque:  147 ft-lb or 200 Nm, then an extra 1/4 turn.

How much does it cost to change the harmonic balancer on a Mercedes-Benz?

An auto repair shop or a Mercedes dealership will charge between $350-$700 to replace the harmonic balancer pulley.

If you change the harmonic balancer yourself, it will typically cost you around $150. You will spend around $50 for the harmonic balancer tool and around $100 for the crank pulley.

Best price on Mercedes-Benz harmonic balancer

You have a couple of options for replacing the harmonic balancer. You can use the OEM balancer or install a new aftermarket harmonic balancer for under $100.

Click the link below to see the lowest prices on Mercedes-Benz harmonic balancer.

• Lowest Price: Mercedes-Benz Harmonic Balancer (eBay link)

Fits:

• 2001-05 Mercedes Benz C240 Harmonic Balancer
• 1998-00 Mercedes Benz C280 Harmonic Balancer
• 2001-05 Mercedes Benz C320 Harmonic Balancer
• 1998-00 Mercedes Benz C43 AMG Harmonic Balancer
• 2000-06 Mercedes Benz CL500 Harmonic Balancer
• 1998-05 Mercedes Benz CLK320 Harmonic Balancer
• 1999-03 Mercedes Benz CLK430 Harmonic Balancer
• 2003-06 Mercedes Benz CLK500 Harmonic Balancer
• 2006 Mercedes Benz CLS500 Harmonic Balancer
• 2005 Mercedes Benz E320 Harmonic Balancer Gas Engine
• 1998-04 Mercedes Benz E320 Harmonic Balancer
• 1998-02 Mercedes Benz E430 Harmonic Balancer
• 2003-06 Mercedes Benz E500 Harmonic Balancer
• 2002-08 Mercedes Benz G500 Harmonic Balancer
• 2003-05 Mercedes Benz ML320 Harmonic Balancer
• 1998-03 Mercedes Benz ML320 Harmonic Balancer
• 1999-01 Mercedes Benz ML430 Harmonic Balancer
• 2002-07 Mercedes Benz ML500 Harmonic Balancer
• 2000-03 Mercedes Benz ML55 AMG Harmonic Balancer
• 2006-07 Mercedes Benz R500 Harmonic Balancer
• 2006 Mercedes Benz S350 Harmonic Balancer
• 2000-06 Mercedes Benz S430 Harmonic Balancer
• 2000-06 Mercedes Benz S500 Harmonic Balancer
• 2001-04 Mercedes Benz SL500 Harmonic Balancer
• 1999-06 Mercedes Benz SL500 Harmonic Balancer

Harmonic Balancer Recall / Service Bulletin

A service bulletin was issued in April 2005. Several Mercedes model years, including 1998-2001 Mercedes Benz MB C CLK E ML R S SLK were identified to have a defective harmonic balancer pulley. The dealers inspected the cars and replaced the harmonic balancer if defective. Approximately 365,000 were affected.

According to Campaign No. 2005020003, which was sent to Mercedes-Benz owners, cars that had the following part number were affected:

• A112 035 00 00
• A112 035 06 00

A copy of this campaign can be found here. See the attached pdf in the comment.

Mercedes Harmonic Balancer Part Numbers

This is a partial list of Mercedes-Benz harmonic balancer part numbers. This list is for reference, and we would encourage you to call your dealer to verify the harmonic balancer part number on your Mercedes by VIN.  Part number change, and there may be an upgraded part that supersedes what is listed here.

• ML320 ML350 ML430 S430 1120351300 Mercedes  Crankshaft Pulley Harmonic Balancer
• 03-06 SL55 CL55 S55 E55 1130300103  -MERCEDESHARMONIC BALANCER VIBRATION ABSORBER
• 1994 Mercedes-Benz E420 1190300103 Harmonic Balancer Belt Crank Shaft Pulley
• 2001 Mercedes-Benz E320 1120351300 Harmonic Balancer Belt Crank Shaft Pulley
• 1996 Mercedes-Benz E300 6030300103 Harmonic Balancer Belt Crank Shaft Pulley
• 2006 Mercedes-Benz C230 2720300903 Harmonic Balancer Belt Crank Shaft Pulley
• W215 CL500 00-06  1120350900 MERCEDES HARMONIC BALANCER
• 2000-2006 MERCEDES 500 430 1120350800 HARMONIC BALANCER CRANKSHAFT PULLEY
• 2000-2006 MERCEDES 500 430 1120350800 HARMONIC BALANCER CRANKSHAFT PULLEY
• ML350 ML430 S430 1120351300 Harmonic Balancer Crankshaft Pulley for Mercedes
• MERCEDES OEM 06-07 R500-1120351400 Engine Harmonic Balancer
• 10-12 R350- 6420300403Engine Harmonic Balancer
• 10-12 C300 2720300903 Engine Harmonic Balancer
• 13-16 GL350 6420302403 Engine Harmonic Balancer
• W163 ML320, ML430 ML55 A1120350900 Harmonic Balancer,