Rotor bearing rough / scratchy

[altdestiny]

Hey Hey all,

Wanting to garner something from the collective experience of the community.
I took rotors off and whilst turning by hand there is a distinct resistance and rough feel that comes and goes in one of the rotors. Im thinking of blowing it out with some air in case a grain of sand or something possibly made its way in there. Any thoughts


Had the mavic a little over a week, last night i noticed the mavic appeared to have a little trouble keeping position stable during a short flight getting a couple of elevated shots of sunset.

I flew it back to me when i first noticed but it sounded fine and seemed to correct but it did start to drift around a little at times.
I got a chance to take it out for 15 min today and during flight seemed fine but when i brought it in to hover i noticed its rotors dropped in and out of harmony and it was drifting a little.

 

[altdestiny]

quick update,

Ok so sand in rotors is a thing not talking pouring the stuff in there but to the point that ill avoid taking off or landing on anything soil'y or sandy whenever possible even if its just taking off a jacket to use as a landing pad.

So
Last night i blew into the rotor with the power of lungs, and spun back and gently by hand, appeared to have reduced the occurance rate that i felt resistance so continued a bit to the point it was no longer significant. Cautiously optimistic at this point

Today i tested indoors for 15min holding position and it was fine, was one glitchy type movement in the whole time and it wasnt severe at all.
continued optimism

Took daughter and dog down the beach and did some low level flight and active tracking.
Flipped it over on the sand, when i went to start it next distinct harmonic imbalance thought aww crap previous rotor not fixed. But as i was shutting it down it occurred to me that i could localize the sound as from the front of the bird not the rear right. Spun the front right rotor by hand sure enough little crunchy and even binded up a Little if i rocked it with fingers each way.
Bagged it up played with the family took it home.

Submission
in short i was able to tap on knee whilst spinning by hand upside down and get a few grains, instead of using compressed air i got the vac just now (ive come to the pc to do update) its all but completely returned the rotor to normal. I'll do a little more work on it and i expect ill dislodge and remove any grit in there.

So even a few grains can bind up the spinning, likely a known fact to the pros out there but thought it worth explaining to those less seasoned.
The reason i went vac instead of blow was that in principle if the vac can remove its better than forcing air in and pushing grit into the crevaces.
Once im fully satisfied on the vac removal ill prob finish opff with a blow to clear out anything that remains.

love to hear any feedback still and hope this helps someone else out there at some point