Can you just instal a "better" roller and pads scavenged from another 8 track tape? In general its also just 1/4" normal bias reel to reel tape in one. You can reload the cartridge by cutting the tape, splicing new tape to it, pull the other end until the new tape comes through, the cut and splice the new ends together. Btw... late production 8 tracks had hard plastic rollers. You might need to rough up the capstan with a bit of fine Emory cloth. We used to use a matchbook cover.