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Pelican Technical Article:

Removing the Crankshaft Pulley

Mike Holloway


1 hour1 hr






13mm socket wrench, breaker bar, 6-inch extension, 27mm socket wrench (optional)

Applicable Models:

Mercedes-Benz R107 (1972-89)

Hot Tip:

Remove any component to provide more room

Performance Gain:

Access to vibration dampener, crank hub and timing chain cover

Complementary Modification:

Timing chain, chain tensioner, tensioner rail, and cam sprocket replacement

Before you do any work on your car it is important that you wear safety glasses, work gloves and dispose of all fluids in a safe manner. Coolant is poisonous and should be treated as such. Animals and small children have been known to die from ingesting coolant. If you have to jack up your car, make sure to use jack stands and chock your wheels as well as applying the parking brake. Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If you're working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Never work on your vehicle if you feel the task is beyond your ability. Always wear eye and hand protection.

The Mercedes Benz 450SL is considered by many to be one of the most attractive cars Mercedes produced. It is a stylized combination of power, grace, and comfort and was sold under the model designation R107. At over 3,600 pounds and designed to meet (and actually exceed) strict safety regulations, the 450SL was nicknamed "der Panzerwagen", which means "the armored car", by the engineers who designed it. The 450SL was produced from 1973 through 1980, after which the R107 became known as the 280, 380 and 500 SL.

The SL variant was a two-seat convertible with a standard soft top and optional hardtop and optional folding seats for the rear bench. The designation SL derives from the German Sport Leicht, or Sport Lightweight and was first applied to the infamous gull wing 300SL. The 450SL was the third generation SL. The SLC (C107) derivative was a two-door hardtop coupe with normal rear seats. The SLC is commonly referred to as a 'SL coupe'. This was the first time that Mercedes-Benz had based a coupe on an SL convertible platform rather than on a sedan, replacing the 280 and 300 SE coupé.

The robust, V-8 powered SL is a joy to drive. Many drivers test the power of the 450SL. While the speed off the line is questionable, the top end performs smooth and responsive, giving the driver a sense of security. The 450SL cruises comfortably at speeds in excess of 75 mph.

One would think that when the engine is at speed there is a higher incidence of wear and eventual failure. This isn't necessarily true in the case of certain components, namely the timing chain. Chains, sprockets, gears and even bearings experience the most wear upon startup. The timing chain and the various components (guide rails, tensioning rail, chain tensioner) wear out after 100,000 miles and should be replaced. The sprockets should also be replaced. The chains can stretch but they also wear. As each rolling element of the link begins to experience wear it sets up for increased vibration and movement of the chain links and pins against the sprocket surface. As many teeth as the sprocket has, the chain has many more links. The sprocket surface wears down contributing to more movement as the chain passes over the sprocket surfaces. This creates an even greater opportunity for chain breakage.

The guide rails will be the first order of business to address. In order to change the guide rails in preparation for the replacement of the timing chain, all the components in front will have to be removed. This includes the belts, pulleys, alternator, the distributor and the power steering pump were all removed. Please refer to these articles should you need edification.

I also removed the radiator. Normally you wouldn't have to do that but it was already out due to the development of another article. Refer to removing the radiator article for help in that regard.

Also, the distributor should be set at top dead center (TDC) and marked. This is needed when you put everything back. The distributor was also removed earlier. Hence, you can refer to that article if you need assistance.

The valve cover will have to be removed as well. In order to do that you will have to remove the air box. Refer to the valve cover removal article for help on how to do that project.

The chain guide is held in place by bearing bolts. These devilish devices provide hours of frustration if not properly dealt with. There are several ways in which they can be removed. The easiest way is to use a tool offered up by Pelican Parts called a rail pin puller guide with a 6mm extractor. Please refer to the removing the chain guide article for more information.

The top guide rails should also be replaced. It is not necessary to remove the timing chain cover to get at the guides but it would make the job easier. The lower ones shall be replaced but require the removal of the timing chain cover. That task is also required for the timing chain replacement. Referring to this article will help you with that project.

In order to take off the vibration dampener and crank hub, the crankshaft pulley has to be removed.

Set the crank to top dead center (TDC).
Figure 1

Set the crank to top dead center (TDC).

The crankshaft pulley is held on very tightly with 13mm bolts.
Figure 2

The crankshaft pulley is held on very tightly with 13mm bolts.

Using a 13mm socket, a 6-inch extension and a breaker bar, loosen and remove the 6 bolts holding the vibration dampener.
Figure 3

Using a 13mm socket, a 6-inch extension and a breaker bar, loosen and remove the 6 bolts holding the vibration dampener. You may have to hold the vibration dampener in place with a 27mm socket held to the crank hub bolt.

The crankshaft pulley is now free.
Figure 4

The crankshaft pulley is now free. Installation is the opposite of removal.

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Page last updated: Sat 10/22/2016 02:45:09 AM