I had help with this task. Adjusting any bearings on a bicycle can be fiddly, but with patience you will always get there in the end!
Here is my Instructable on the first step of rebuilding my bike.
Fitting the forks and headset!
Forks: the bit of a bike that holds your front wheel, and steers!
Headset: the parts of the bike that attach your forks to your frame, and allow them to spin freely.
Step 1: Bare Frames, Back From the Painter's Workshop.
Step 2: Prepare Your Headset Components for Rebuilding.
Cut the cabletie, and lie the headset parts on your worktop in the right order, the right way up!
Clean each component to remove old grease and dirt, any solvent will do.
Whilst cleaning, check any part for signs of damage or wear.
A nice trick is to run a ballpoint pen along the surfaces that the bearings touch, if you can feel roughness through the pen, that part probably needs replacing.
We recommend buying new bearings rather than reusing your old ones.
Step 3: Fit Headtube Races.
We were lucky enough to have a proper headset press tool which makes installing the races a doddle.
If you haven't got access to the proper tool you could press them in with a large vise, being careful not to damage the races.
You can also knock them in with a mallet, but put a woodblock on top of the race so you don't damage them!
When properly installed, both the races should fit snug in the headtube and be in line with each other.
Step 4: Fit Crown Race.
Slide the crown race down the fork steerer tube. they either slide into place easily or can be quite difficult. Ours was difficult, so we used a piece of plastic pipe and a rubber mallet to knock the race into place.
When fitted correctly, should be sitting snug and flat on your forks.
Step 5: Install Headset Bearings.
We used caged bearings that makes installing them a lot easier, but you can use loose bearings if you want.
If you are using loose bearings and not sure how many to put in, then put in as many as you can, and then remove one.
The caged bearings must be installed a certain way up. It should be fairly obvious which way they need to go, they will fit nice and snug into the head tube races when installed the correct way.
After installing the bearings, put some more grease over the top.
Step 6: Finishing Off the Headset.
Take the lower adjustable top race and screw it down the fork steerer tube until it sits on the bearings.
Many headsets have a tabbed washer which goes on next.
Then take the final headset lock nut and screw this down your steerer tube.
Don't worry about tightening it up too much at this stage.
Step 7: Final Adjustment!
Check for wobble by holding the frame tight in one hand, and hold the forks near the headset with the other. See if you can create a knocking feeling by pushing and pulling your hands apart.
If there is a knocking feeling, the headset needs to be tightened.
If there is no knocking feeling, try the steering to see how it feels. If it feels stiff you will need to loosen the headset.
You adjust the headset by either tightening or loosening the lower adjustable headset race. We used a headset spanner, but often you can do this by hand.
Once your headset is adjusted correctly, hold the lower adjustable headset race steady whilst tightening the top lock nut.
Step 8: Finished!
If your headset doesn't look at all like this, you've probably got a threadless headset, which is a whole other Instructable... watch this space!