I have inserted a mini video to demonstrate what I am changing and clear symptoms of its need.
Step 1: Supplies
I am using a 68/72mm Shimano Bottom Bracket Bearing SM-BB52
You will need:
Your new bearing (SM-BB52)
a 5mm Hex wrench
Hammer (and small Block of wood)
Bottom Bracket Tool (Park Tool # BBT-9)
A rag or two
about 30 minutes of your time
Step 2: Remove the Cranks
1. Derail the chain (you can leave it hanging on the Bottom Bracket for now)
2. Using the 5mm hex wrenches remove the 2 hex bolts on the left crank.
**take note which way the small spacer is positioned in-between the split in the crank where the bolts are**
3. Using the BBT-9 tool use the small wheel end and remove the nut that is on the end of the spindle
3. Simply slide the Crank arms off the spindle
Step 3: Remove the Spindle and Old Bearings
1. Using the BBT-9 tool over the grey nut rotate counter-clockwise on the non-drive side to loosen
**Take note of any spacers that are in-between the nut and the frame of your bike they are important for the spacing of your derailleur and chain**
2.Slide the nut off
3. On the drive side you can remove the spindle from the bearing
4. The nut on the Bottom Bracket bearing on the drive side must be turned clock-wise to loosen
**remember to take note of any spacers**
5.Be sure to remove the tube inside of the frame that was between the left and right bearing
6. Clean up the Bottom Bracket housing as you do not want any dirt or grime as that will defeat the point of replacing the bearing
Step 4: Reinstallation of New Bearings
Reinstallation of the Bearings is exactly the opposite of removal with a few exceptions
- you may need to tap the spindle in the last bit after you carefully slid it into place making sure not to rip the seals of the new bearings.
- If you need to persuade the spindle use a block of wood and a small hammer and carefully tap it in place
- It must be fully seated right up against the bearing nut
- the Crank arm can only fit on one way based on its splines
- before you tighten the hex bolts on the crank tighten the end nut of the non-drive side crank to tighten it in place.
- be sure to put the tab back in the split on the crank arms. **tighten evenly**(a torque wrench is recommended)
- if the tab does not sit flat like it did originally the spindle is not in far enough (also)
- if you grab the 2 pedals and if there is any play side to side you need to tighten the spindle in closer to the bearing nut.
- put the chain back on and adjust the front derailleur if needed
----- Happy Riding ----