how to service a DaBomb headspin hub?

Since 2001, over 90,000 cyclist's have joined Cycling Forums to discuss topics from general cycling to equipment, training, racing and travel or vacation destinations (especially in europe during the tour de france). We also feature an great deals in our online store, 100's of articles, classifieds and product reviews.

Hi guys, newbie here,
i bought a used rimset (alex dx32 with dabomb headspin hubs)
after a few rides i noticed that when i turn the cap of each end, the feeling is kinda grrity, but theres no play or wiggle,
should i replace the cartrige bearings or is there another way to remove the grrityness feeling when my hub freewheels?

how do i replace the cartrige bearings? my friend told me that i just have to remove the caps and just hammer down (with a wood 2x4 or a rubber mallet) the shaft till the cartrige bearing pops out, is this correct?
can i just use any replacement cartrige bearing from a bearing shop?

tnx guys! :)