Aaron,

The bearings are 1/4" torlon bearings and can be purchased considerably cheaper at http://www.mcmaster.com - their service is awesome too. Part number is 9593K17 - I just replaced all the bearings in my traveler and have enough to replace one side of the traveler a second time for $30 (two packs of 50). Check the harken website to see how many bearings should be in the car - sounds like you may have been missing a few to begin with.

The older style Harken traveler cars do not keep the bearings captive when off the track so the special tool is pretty useful. However, (don't laugh - it worked!) I replaced the bearings in the same car on my 5.2 using K-Y jelly to keep the bearings in place while the travler was put on the track. Once installed, you can just wash the jelly away with water since the KY is water soluable.

You want to be carefull not to use a lubricant that is greasy or oily (like WD-40) because these tend to attract dust and sand over time and can cause more wear than they prevent. For long term lubrication, be sure to use a dry (silicone) lubricant or sail kote.