So after this weekend’s ride, I had a long road ahead of me.
Predominantly because the Schweet Mukluk was loaded up with muuuuuuuud. This was more than dry cleaning could handle. So I gently washed off the mud with bubbling water, and looked at the disaster that my drivetrain was. For the chainrings and cassette, I used some water and diluted Simplegreen, with a brush, to scrub the mud and grass out, followed by compressed air to finish the cleaning and dry things off. For the chain, I did the oil + wipedown with a rag + pressurized air technique that has now become standard for me.
That sounds like enough, right? Wrong. The rear derailleur looked like this:
I wasn’t sure if those idler gears just needed to be brushed off, or if they had gotten contaminated inside…so in the name of caution, I pulled them apart. That was a good idea. Step 1: Grab your rubber gloves. (Hey, it’s RATG). Then, grab your 3mm allen wrench.
Both of the idler pulleys are held in place with a single allen screw. The basic design is a plastic pulley, with a caged ball-bearing in the middle. The caged bearing has rubber seals with metal inserts. Outside of those rubber seals are plastic washers that are sandwiched between the metal derailleur arms.
When you unscrew and remove the allen screw from the idler pulley, the pulley will come out of the derailleur with the seals and washers. Mine looked like this:
That’s mud. (On a towel). In the middle of the idler, you can see the black plastic washer. Spray it down with a little diluted Simplegreen:
And with your finger, take the plastic washer off of both sides.
The washers are directional, but it’s easy to see which side goes to the idler, and which side goes to the derailleur cage. Once you’ve cleaned the mud off of the outside of the derailleur, get a small tool (I use a dental pick) to carefully remove the seal:
It’s not hard…just start at the metal center of the wheel, and carefully pick up the edge of the seal.
And the inside looked like this:
Yup. Grease + mud. Riding through the mud (and creeks) will do that.
The seals are directional too. The outside is just rubber, and the inside is rubber with a metal track. These were filthy, too.
I used Simplegreen, and ultimately some CFC free, plastic safe brake cleaner to clean out the caged ball bearing.
And then cleaned the inside and outside of the seal.
And then I packed that sucka’ full of some grease. In this case, I’m using Park’s water-resistant, bike-specific grease. (Although frankly, once I’m done with this tube, I’m going back to my Farm & Fleet high pressure/high temperature water-resistant grease. I think it holds up better).
Carefully reinsert the seals on both sides, with your finger and a little (little) pressure. Make sure they’re evenly sealed, and clean off the excess grease. Then, hold the plastic washers in place. Spin the idler in your hand for a minute to make sure the grease gets nicely distributed within. Then, clean off the balance of derailleur parts (and repeat this process on the other idler).
Things look like this, cleaned and reassembled:
Yup…that looks much better.
Lube the chain, and she’s ready to ride…against the grain.