Need Help!- Procedure for changing Z belt

[KurtsKustom]

Yep, we broke it today trying to get the Z to home. The Z is still trying to home in the negative direction, then hits the lower limit switch. It happened during a handwheel move. It looks like it would go over the top of the shaft from what I can tell from my preliminary disassembly.
Thx!

[jpawelk]

I sent you a PM regarding as to why the axis is moving the incorrect direction. What type of machine are you replacing the Z axis belt on?

[KurtsKustom]

Partner IV.
I have the bolts out of the bottom of the screw's bearing housing, and turning the timing pulley/gear drops the screw down and out of the top of the upper housing with the upper bearing. Top bearing is off the screw's shaft now. The screw will have to come down and out of the nut, I presume, then threaded back in/up/through the nut after the belt is on. It looks like the timing pulley has to come off or be moved? It is larger than the lower bearing, and my progress stops there.
Thx!

[bborb]

Don't take the ballscrew out of the ballnut, bad idea.

[KurtsKustom]

Yes, I decided against that. Rather, I'll pull the nut after unbolting it from the head, and pull it forward with the screw in it to mount the new belt.
Thx!

[KurtsKustom]

OK, here's the prodedure. I installed the belt from the bottom. Pull the bearing housing from the bottom of the head, unlock and remove spanner nut, and drop the bearings (there are 2, both taper cone rollers, facing each other). I'm going to replace these 2 lower bearings as long as I'm in there. Slip the belt over the bottom of the leadscrew, and work it up into position. Reassemble. That's it! I got replacement belts from KSC Direct for under $9/ea. These are exact replacements for what was installed.
Thx!