[R-390] Lubrication of KC and MC Bushings

[Barry Scott]

Hi Jim,

I cleaned the gears and lubricated their pivot points along with the rack
rollers about five or six weeks ago but it seems the KC and MC shafts have
become harder to turn since I reassembled everything.  From what I can
tell, the friction seems to be coming from that bored hole between the
front panel and the PTO.

Unfortunately, I don't think that assembly (the spindle, gear, ten-turn
counter, etc.) is documented in the TM 11-5820-357-35 or the TM 11-856
manuals but I suspect there may be a mechanical assembly manual somewhere.
I figure the parts are in the latest PDFs of the bits and pieces but would
like to see an assembly if possible.

I think perhaps I can set the radio face down, apply a couple of drops of
oil from the side where the Oldham coupler for the PTO is, and let gravity
help out.  If that doesn't help then I may be taking some of the gear train
back apart with the intent of pulling that shaft out of those bushings and
see what I can see.

Thanks,
Barry - N4BUQ


On Fri, Oct 4, 2024 at 4:38 PM Jim Whartenby via R-390 <
r-390 at mailman.qth.net> wrote:

> Barry
> Have you cleared out all of the old grease in the gear train and lubed
> just the pivot points?  Years ago, one of my R-390A/URR was so gunked up
> that the MC knob would not rotate.  After cleaning with solvents and
> detergent, and a drop or two of synthetic oil on all of the pivot points,
> it was very easy to turn.
> Jim
> Logic: Method used to arrive at the wrong conclusion, with confidence.
> Murphy
>
>     On Friday, October 4, 2024 at 03:40:36 PM CDT, Barry Scott <
> 72volkswagon at gmail.com> wrote:
>
>  Is there an "official" method of lubricating the bushings where the KC and
> MC shafts extend through the spider-supports and their associated bushings?
>
> I thought there was an illustration somewhere in the manuals that shows
> where the lubrication points are but I cannot seem to find that now.  I was
> hoping that might show those bushings but I don't know that for sure.
>
> I'm asking all this because the KC shaft is starting to become a bit more
> difficult to turn and I'm wondering if those points might be the problem.
> It isn't due to the threaded bushing that goes in the front panel because
> I've loosened that one to make sure it can float as needed so I'm looking
> at the bushing(s) in that part of the frame as a possible cause.
>
> Thanks,
> Barry - N4BUQ
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html