How to replace rear axle bearings on a mountain bike?

Question

How to replace rear axle bearings on a mountain bike?

Answer 1

1) Remove the wheel from the bicycle. Remove the quick release axle if equipped.

2) Remove the freewheel (if equipped) or cassette

3) Remove the locknut and bearing cone from ONE SIDE, slide the axle out.

4) Remove the cassette body (if equipped). Be careful not to lose the bearings inside.

5) Remove the dust caps from both sides of the hub.

6) Remove the bearings and COUNT THEM. The total number of bearings should be an even number.

7) Clean the bearings, axle, cones, and hub using a good degreaser or WD40.

8) After all parts are dry, take a small amount of white lithium grease on your index finger and wipe it in each side of the hub.

9) Take an additional small amount of grease on your finger and "roll" each bearing around until coated. As the bearings are coated, place them in the hub.

10) Reinstall the dust caps

11) Install the cassette body (if equipped)

12) Reinstall the axle the same way it came out.

13) Install the cone, and other hardware, and locknut. Adjust bearing cone so there is no play and no roughness in the bearings.

14) Install the freewheel or cassette

15) Install the quick release

16) Install wheel on bike

Answer 2

Mirage's instructions are good.  If you have cartridge bearings instead of loose-ball, then you'll need totally different instructions and tools.  Also, if that's the case be sure not to obliterate the rubber seal on the cartridge because in teeny numbers it has the model of the bearing that you should use for replacement.  There are many types of hubs out there, many with different types of axles and assembly methods, so if you can post up what you have we can help better.  

Also, if they're loose ball, when you get in there inspect the bearings and races for rust and pitting....clean them up and look at them carefully.  If they're not perfectly shiny and smooth then pick up some new bearings at a bike shop for a couple bucks.  While you're at it, it's a good time to squirt some heavy oil into the freewheel/cassette body and lube the quick release bushings.  

If you want some good photos and instructions for a few different kind of hubs, check out the "repair help" section at http://www.parktool.com  

Answer 3

Mirage's (bikeworks?) step-by-step takes you right through the process.

The only thing I'd add would be step #2.5

>>> Prior to loosening the locknut and removing the cone on one side, take your wrenches and make certain the locknut/cone on the other side are good 'n tight.  Discovering after-the-fact that the "fixed" side did indeed loosen makes for some frustration and additional work.

I learned this the hard way...