Once the action rack is separated from the key frame, the key set is removed and the key frame checked against the key bed for warping or other types of damage. I usually bed the frame empty once or twice just to see how the key end blocks are set up and, once tightened down, observe if they interfere with the bedding of the frame in certain areas.
When the key frame is seated well into the bed, the key frame is then removed and rebuilt with the usual replacement punchings on front and back rails, along with bolster cloth or key end cloth. When replacing cloths, by using the same grade of materials or close to the original, and by taking into account overall wear, this keeps the adjustments to a minimum when regulating after cloth replacement.
The key set is completed in the usual way; replacement back check felt and buckskin, key bushings replaced top and bottom, and the original ebonies are re-ebonized and coated with a satin or flat finish. The original ivories, if still found on the instrument, are cleaned, whitened, and polished.
Also here is a photo album of key bushing repairs.