Thanks for the reply Harry,
In the meantime, I couldn't wait for feedback , so I went ahead and here's what I did in case someone else needs to do it in the future:
The Makita 3600BR is some 20 years old – I think its simple and very well built.
To take it apart, you remove the height adjustment screw and spring and then
separate the height adjustment from the body.
The body has 2 screws for a metalic cover and 4 longer ones which hold the
body together. Once these screws are removed, you can separate the
body in two parts – the rotor with bottom housing and stator.
The bearings are on the rotor one on each end. I found out they were very clean so
I didnt even take them off, just greased them with some lithium grease.
In case you need to remove them, clamp the rotor by the winding in a vise using
some softwood blocks on the side to avoid damaging anything. The top bearing can
be removed with a pulley. For the bottom bearing, turn the rotor over, clamp in
vise again and unscrew collet holder. Now find some softwood blocks of wood which
will stand upright and hold up the bottom housing at top and rotor below. Softly tap the rotor axis with eg some hardwood dowel (at least I wanted to avoid any damage). The rotor will pop out (down) out of
the housing and the bottom bearing (on the top of the axis) will be able to be removed with a pulley.
I suggest you check if bearings are OK (top one should rotate fairly freely, the bottom
larger one may be a bit coggy) and decide if its worth taking them out. I always think
its better leaving something alone if it works. Grease them and reassemble in reverse order.
I then applied some machine bed paste to the height adjustment rods and hand turned
the rotor to check if everything was OK – well, everything went great, motor
sounded great and height adjustment was so smooth – well, that felt good especially
since in the beginning I was a bit unsure on how to clamp the rotor without damaging it.