An off-track door usually comes down to one of three things: a bent or dented track, rollers that have worn down and started jumping the rail, or a cable that's frayed enough to let one side of the door drop while the other holds. We carry replacement track sections, steel and nylon rollers, and lift cables sized for the residential doors that make up most of Milpitas - houses built through the 1980s and into the 1990s, on standard 7-foot and 8-foot openings. What we don't stock on the truck are oddball parts for older or custom doors. If your track hardware turns out to be a discontinued size, that's a special order, and we'll tell you before we quote the job, not after.