Replacing spherical bearings at the wing root? (Grob Astir CS)

On Tuesday, March 3, 2015 at 1:45:06 PM UTC-8, Eric Munk wrote:
I would say LTB Lindner would have all the details. They are Type
Certificate Holder for the Astir CS I believe. Changed a fair few myself,
not a big hassle. There's a clearance to be observed in most Grobs wings
attachments (see manual) regarding wear limits. Often overlooked. Check
your other fittings for that too whilst you are at it.

At 20:47 03 March 2015, Movses wrote:
The spherical bearings that mate to the spar spigots in my Astir CS are
binding when turned to larger angles.
When rigging the wings, a slight misalignment of the spigot jams the
bearing and any further progress becomes impossible until you pull the
wing
out and unjam the bearing using a wooden dowel (it wouldn't turn by hand
once jammed).
This makes putting wings together a royal PITA.

Closer look revealed that the far side of the "outer race", is worn out
and
pitted and likely is the culprit.

The bearing in question is SKF GE 20 ES, which seems to be easily
available.

It appears to be pressed in into a metal sleeve that is bonded into the
wing root, and four areas are punched in to further lock it in place.

We couldn't find anybody local who would readily know the process of
replacement of that bearing.

Is anybody familiar with maintenace/replacement of these?

- Is that bearing replaceable? It seems like the only way to extract it
is
to slide-hammer it out and tap a new one in.
- How critical is it? I assume that it radially transfers the entire load
of the wing

-Movses



Wrote to Lindner and heard back. They're saying they never had to deal with replacement and basically don't know.