Original BMW Adjusting Pulley with Lever Assembly for the S85 V10 Accessory Belt, BMW E60 M5 and E63/E64 M6 (2006–2010)

On the V10 S85 engine in the 2006–2010 BMW M5 and M6, this Original BMW adjusting pulley with lever holds steady tension on the serpentine belt that drives the accessories. BMW names it the adjusting pulley with lever, so the pulley and its tensioner arm come together as one assembly. It is made in Slovakia and sold as a single unit. A belt tensioner keeps the accessory belt from slipping so the alternator, pumps, and air conditioning compressor turn as they should. The usual failure on this pulley is its internal bearing running dry, which makes a loud noise with the engine running, and a dry-running pulley can come apart while the engine is running, a far bigger problem than the noise.

Original BMW Parts carry a 24-month parts warranty.

The current number went into production in January 2007 and replaced 11-28-7-834-256. BMW rates the change as exchangeable retrospectively, so the newer assembly also fits earlier S85 cars. Because the pulley wears along with the belt, replacing it when you fit a new serpentine belt is good practice and heads off noise or early wear on the new belt. Belt bounce or hop points to a weak tensioner. A power steering pump or air conditioning compressor that drags can mimic a bad tensioner, so spin the other pulleys and accessories to confirm they turn smoothly before ordering.

Technical Details

• Manufacturer: BMW (Original BMW Parts)
• Part number: 11-28-7-839-133
• Official name: Adjusting pulley with lever
• Engine: S85 V10
• Production start: January 2007
• Replaces 11-28-7-834-256, exchangeable retrospectively
• Country of manufacture: Slovakia
• Sold individually, one assembly
• Warranty: 24-month parts warranty

Common Questions

Does this fit an early 2006 M5 built before January 2007?
Yes. BMW rates it as exchangeable retrospectively with the earlier 11-28-7-834-256.

What are the signs of a failing tensioner pulley?
A loud noise with the engine running from a dry bearing, or a belt that bounces and hops.

Should I replace the belt at the same time?
Fitting a new pulley with a new serpentine belt is good practice, since both wear together.

For S85 belt work, PMB Performance can help you gather the pulley and related parts in one order.

Fitment & Compatibility

Check the table below for the exact year, model, submodel, and any listed notes. PMB Performance has spent over 20 years matching parts to vehicles and can verify this against your VIN.