Clean and Polish a Bike's Derailleur

Begin by changing the gears to the smallest sprocket (or highest gear). Flip open the wheel’s quick-release system and remove the wheel. Use appropriate tools to loosen the cable crimper bolt and cut off the cable end cap. Unthread the cable from the rear mech to prepare for removal.

Before removing the derailleur, carefully unthread the bike’s chain from it. Unscrew the upper pulley bolt to detach the chain. Once free, unscrew the main bolt of the rear mech hanger and remove the derailleur, supporting it to prevent damage.

Organize and unscrew the different parts of the derailleur, starting with the pulleys. Use the appropriate tools, such as Allen keys and Phillips screwdrivers, and keep all components neatly organized to facilitate reassembly later.

Scrape off dirt and grease from the derailleur parts using a slotted screwdriver. Soak the parts in a container filled with degreaser, then scrub each one using a small brush. Rinse with clean water and dry thoroughly to prepare for derusting.

Secure the Dremel Multi-Vise to your work surface and attach the Multi-Tool. Insert and tighten the Brass Brush (535 or 537) and run each part against the spinning brush to remove rust. Use Brass Brush 537 for hard-to-reach spots.

Attach the Mandrel (401) to the Rotary Tool and screw on the Polishing Point 422 or Polishing Wheel 414. Apply Polishing Compound (421) to the accessory and polish each part thoroughly to restore its shine.

Grease the pulley wheels with ball bearing grease, then carefully reassemble all parts in reverse order. Pay close attention to the pulley wheels' placement and ensure correct alignment.

Check the mech hanger for damage before sliding the derailleur back onto it. Secure the derailleur with the hanger bolt and thread the cable through it. Crimp the cable end cap securely.

Guide the bike chain over and around the cassette, and then thread it through the upper (guide) pulley. Next, guide the chain through the power pulley’s Guide the bike chain back over the cassette and through the pulleys, ensuring correct alignment. Reinstall the rear wheel and tighten the quick-release handle.

Fine-tune the derailleur's adjustment by turning the high and low-limit screws to ensure smooth shifting. Once adjusted, wipe the derailleur clean and you're ready to hit the road!

Follow these steps carefully to restore your bike's derailleur to optimal condition, ensuring a smooth and enjoyable ride. Remember to prioritize safety by wearing eye and respiratory protection throughout the process.