HET Y Roller Screw Rep.

Data Archive

Y Roller-Screw Retainer Nut/Bearing Replacement

Procedure and photos from 2 May 2002 when we replaced the BearLok retainer nut and the fixed bearings on the upper end of the Y Roller-Screw.

The replacement went very smoothly. The procedure essentially consists of

Tie off the tracker at the upper end of its travel.
Remove the track motor, brake housing, and bearing covers.
With counter torque at the lower end, remove the Bearlok nut.
Remove the Bearing Housing and the bearings.
Replace the bearings and the Bearing Housing.
With counter torque at the lower end, replace the Bearlok nut.
Replace the track brake housing and the tracker motor.
Do great science.

We did find that the original bearing retainer cap was seriously bent around the rim, the bearings were damaged and loose in their race, and the bearing housing bolts were bent. Additionally the bearing grease smelled burnt. The grease had leaked and discolored the lead screw. We also found that all the ears on the retainer nut were broken rather than just one as we had originally thought. These are believed to have been caused by the tracker crash of 15 May 2000. The resulting upward bounce drove a lot of force into this area.

Procedure Rev 1 dtd 24 April 2002 (Word Document).

	Y tracker assembly with brake housing removed.
	Damaged socket cap on motor mount.
	Y tracker motor removed. You can see the flex coupling.
	Lower end of roller screw with BH-07 retainer nut. A 1 1/8 inch open end wrench fits this shaft.
	Rex Barrick hangs out and adds his own commentary.
	Rex holds counter torque at lower end of roller screw.
	Gently (?) tapping bearing housing in order to remove housing and then bearings.
	View of roller screw showing discoloration and leakage of bearing grease.
	Close up of discoloration.
	Home brew torque tool for upper Bearlok nut.
	Placement of torque wrench.
	Robert P. putting torque on retainer nut.
	New bearings and nut in place.
	New inspection cover half installed.
	New inspection cover fully installed.
	Track motor and brake housing are reinstalled.
	Damaged retainer nut.
	Damaged bearing housing bolts. Note slight bend to bolts and damaged flat washers.
	The old bearings.

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Created: 2-May-2002
Last updated: 01-Oct-2003