No mystery to it. Here is exactly what happens from the moment you call to the moment we hand the job back.
Each dock assessed for what has actually failed, with the door opening measured and the trailer mix noted. A survey covering all positions usually finds a mix of repair and replacement.
Fabric weight, seal type and wear protection matched to how hard that position is worked, rather than applying one specification across a whole facility uniformly.
Positions taken out of service in sequence so shipping continues. This planning is usually the constraint rather than the labor itself.
Old unit removed and the mounting surface inspected. Deteriorated masonry, corroded angle or a damaged jamb is repaired before the new unit goes on.
Unit fitted and checked against an actual trailer rather than by eye, confirming the seal closes at the top and both sides with the door in service position.
None of this is required — it just makes the visit quicker.