Leveler types. Three categories: mechanical (spring-and-counterweight, lowest install cost, highest maintenance), hydraulic (pump-and-cylinder, smoothest operation, longest life, highest install cost), and air-powered (inflatable bag, mid-range cost, popular in food service and pharma where hydraulic fluid contamination is a concern). Cycle ratings: residential 5,000/year, light commercial 10,000, heavy distribution 50,000+. Spec the leveler to your truck count per shift, not to your dock count.
Seal and shelter types. Head-curtain only (lightest, used when trailer width is consistent), full surround foam (compresses against the trailer for tighter seal, used in conditioned facilities), and inflatable shelter (powered, used in cold storage and pharma where seal integrity is most critical). Selection driven by trailer width variance, fleets with consistent trailer widths can use simpler seal designs; mixed-fleet docks need adaptable shelter systems.
Vehicle restraints. The most-overlooked component, and the one OSHA cares about most. Manual chock (cheapest, easy to forget, lowest insurer rating) through electronic motor-driven hook (highest reliability, integrates with leveler interlock, required by some insurers). OSHA 1910.178 and most insurer requirements mandate that the restraint must engage before the leveler can lower, meaning a forklift can't drive onto a trailer that isn't secured. We document this interlock test on every install.
Dock lighting and communication. LED dock-arm lights (replacing the old halogens, 80% energy savings, longer life), pit-mounted indicator lights (status to the truck driver outside), interior status lights (red/green to the forklift operator inside), intercom systems for driver-coordinator communication, and RFID for fleet tracking. Specify communication requirements alongside the leveler, adding them later means tearing into the dock face twice.
Preventive maintenance importance. A leveler that's been running on degraded hydraulic fluid for two years is the most expensive repair on a dock, typically $4,000–$8,000 for full hydraulic system replacement. Quarterly fluid inspection, semi-annual seal replacement on the cylinders, and annual restraint-engagement testing prevent ~80% of dock equipment failures. Service contracts →