Door vibrates excessively or shudders when opening or closing.

Safety first: Do not attempt to adjust torsion or extension springs yourself; this is specialist work.

• Check track alignment: With the door closed, verify that the tracks are plumb and parallel. Loosen mounting bolts slightly, adjust, and re‑tighten.
• Inspect rollers: Replace any rollers that wobble or have flat spots.
• Check panel fasteners: Tighten hinge screws and brackets on the door panels.
• Have springs serviced: If the door is out of balance or one side lifts higher, arrange for a professional to adjust or replace the Cardale spring set.