Intro and stuff.So, say you (like me) have a Shimano external bottom bracket. And say you (like me) have noticed a little grinding recently. And say you (like me) hate to spend money on what should be maintainable equipment. Out of luck, right? Au contraire mon frere! (In US English that translates to, “I don’t think so, chump!”) With a little creativity and some patience these are just as serviceable as any other bottom bracket.
ProcedureStep 1: remove the cranks. Whatever issues I may have with Shimano, I have to admit that they try to make things as user friendly as possible. Removing these cranks is no exception. A tip here: if you don’t feel like buying a special tool to remove the end cap from the crank, you can wedge a pair of needle nose pliers in there and get it out. If you ruin the thing, replacements are only a couple dollars.
Step 2: remove the plastic shim / dust cap. This is the trickiest step. The easiest that I have found is to use a long, narrow screwdriver. Wedge the end in from behind and gently tap around the back of the cap until you can get a grip on the front. From there just pull it out with your fingers. Take care! These are not designed to be removed and so are a little brittle.
Step 3: Remove the rubber seal from the bearing. It works best to use a small, narrow tool. I used a small eyeglass screwdriver. A paper clip might also work.
Step 4: pack the bearing with your choice of grease! A synthetic works best. If you have the urge, Phil Wood and (I think) Hope both make well regarded bottom bracket grease. They run you a little more, but may be worth it to you. I like Pedro’s, but Park is probably just as good.
ReassemblyPretty straightforward. Just reverse the steps! As with disassembly, use caution when inserting the plastic shim / dust cap. If you press it in crookedly, it could crack. A flat piece of wood could be handy.
So go out and give it a try! Even if you mess it up, what have you lost? 20 minutes and a piece that you were going to throw away anyway. Also, you can use these steps to get at the bearings themselves, if you decide you want to keep the BB and slap in some Enduro bearings.