Procedure to Free 40 Meter Mast Bearings   40.yagi.bearings.procedure.htm

Drafted 19 September 2014

Loosen bolts attaching mast to rotor. Done 10/19

Test that rotor turns both directions. Note direction. Done 10/19

If rotor does not operate correctly, replace rotor and verify operation. N/A

Retighten mast to rotor. Done 10/19

Attach safety U-bolt above top plate and a second one 6 inches above the first. First bolt done 10/19

Loosen three bolts on top bearing that clamp into the mast and free mast from bearing body as much as possible. Try to rotate bearing sleeve. Done 10/18 and 10/19. No amount of effort, cleaning, force, or solvent would free the sleeve from the mast.

If mast turns with rotor, then bottom bearing is OK. At this point, attempt lubrication of top bearing, clean paint, try to get mast to turn with bolts tightened.

If mast still does not turn with rotor, then bottom bearing is jammed. Do all possible to get out bolts on bottom thrust bearing, and chip off all paint. If necessary, grind off bolt heads on top until thrust bearing is separated from rotor plate. Bolt heads ground off 10/19. Bolts had to be pounded out from bottom. Grinding heat enabled bolts to be freed.

If mast turns, dragging the bottom bearing along with it, do all possible to free mast from bearing. If mast turns well with rotor and with the bottom bearing loose and the top one tight, bottom bearing needs to be replaced. Mast turns, dragging bearing on top of rotor plate 10/19. Mast still bonded to bearing.

Remove rotor, slide new bearing and rotor plate onto mast, then restore rotor.

Working from above, cut out the old rotor plate and as much of thrust bearing as possible.

Slide up new rotor plate with bearing into place. Test for proper rotation, which should work fine.

Attach come-along clamp low on mast.

Remove rotor.

Use come-along and attempt to pull mast down through bearings.

If it pulls, remove bottom safety U-bolt above top plate and lower mast down six more inches.

Cut off requisite bottom of mast.

Reinstall rotor.

Clean, paint, and splint bad areas of mast as needed.

Paint new bearings and hardware.