Replaced non-functioning L4C (L4-C) sn L41367 with L41365.  Looks okay, will continue testing.

How?  Deisolated platform.  Locked only corner2 foot to Caging brace (oh yeah, had to adjust rear caging brace to proper position) w/ ~5mil + bias from Ready state--the Actuators tend to pull a few mils (5-10) from the nominal shimmed position.  Disconnected Actuator from brackets but did not loosen brackets hoping this would help retain position.  This won't always work.  Shimmed and locked down actuator.  Disconnected Actuator from Foot.  Powered down Pier Pod, dewired, and removed it and the holder bracket (to get access to L4C Clamp bolts.)  Removed the two Horizontal Actuator Adapters.  Loosened the three L4C holder bolts, loosened the two L4C clamp bolts.  Left the L4C leveling shims in place since we really level the holder, not the L4C.  Pulled the L4C and clamped in the replacement.  Rewired to check spectra--looked okay.  Dewired again.  Reversed process: Actuator Adapters, Actuator to Foot (worked nicely, all the bolts went in smoothly,) Bolted Actuator to Brackets (Housing,) rewired Pier Pod.  Numbers look very similar to before.  Unlocked Actuator and removed shims.  Unlocked Foot--position within 200 counts of position before.  Reengaged Isolation, no problem.

Now the position could actually be different but I really don't think by much (a few mils at the worst) and I don't think ISC is that sensitive here.  But, feel free to drive it to where it is needed.