I took my son out in the trailer today, and had a weird clicking noise from the front end. Getting home I decided to address it. This is on a Giant Toughroad (rigid 29er).
Wound up doing basically a full tear-down and rebuild.
1) Cleaned up headset.
The lower bearing literally fell out of the frame when I removed fork. I suspect the noise was a loose headset. Headset might be too tight now. It may be worth taking it to the shop for this and the front hub...
2) Adjusted cones in the front hub.
Wouldn't spin smoothly, maybe I got it now, but what a pain. The cones are either way too loose and don't stay adjusted, or so tight the wheel binds...bleh. Makes me want to just upgrade to a cartridge bearing wheelset...
3) Swapped the stock Shimano M355 hydraulics for an old set of XTR's off another bike.
Required doing a full bleed, since I needed to perform a caliper swap.