A few months into having an operational 301 I returned to the condition of the drive-motor and itís bearings. What is really simple to grasp turns out to be relatively involved, if only in terms of access, situated as it is directly at the center of the turntable mechanics.
motorís rotation is fixed on itís axis at two points, an Upper
Bearing which serves as a guiding collar to steady the rotation, and a Lower
Bearing which not only steadies and centers the rotation, but also
serves to support the whole rotor-shaft as well.
is meant to be well coated in electric-motor oil, and kept supplied with said
oil via an absorbent felt washer adjacent to the bearing assembly. When the felt
washer is saturated with lubricant it provides a reservoir with which to keep
the bearing and thrustball coated.
When I first came to the motor bearings, I reasoned that since motor rotation felt smooth before the lubrication, I could add some additional oil and call it satisfactory. Well, partly true, but with a fifty year old mechanism itís all-around better to get in there and clear out the old lubricant, start fresh with a squeaky-clean bearing that youíll soak with brand new lubeÖ.
If itís the base for the motorís rotational action, itís the basis of the turntableís performance, so thereís every reason to be sure that it is free of any oxidation or debris, and well packed with lubricant.
the next level is to get at the motor's lower bearing and thrustball, for
which you need to do the following :
unit unplugged from power, set lever to Off and disengage eddy-current brake
via pitch control (ie rotating pitch all the way to "+" moves the
brake-shoe away from the eddy wheel & avoids damage when deck is on it's
do not loosen upper motor bolts, do not remove stepped motor pulley, or eddy-current
disc from drive-shaft. You'll be leaving all of that as set by
pull circlips off the three bottom spring-mount Pins, and then disengage motor
from bottom springs by pulling pins. 'Leaning' motor toward the pin/mount you're
removing lowers the spring tension and eases the removal process, but don't
over-stress other springs--- they can be stretched too much. Also detach AC block
remove nuts from bottom-half 'clam-shell' casing of motor
in a precise straight up motion remove bottom clamshell. Do nothing
'side-to-side' that could nick or graze motor shaft, or the softer part #99, the
Rotor Bearing, while sliding upward.
use a lintless rag to "wick out" the bottom bearing. Clean with
solvent like lighter fluid the base of the rotor shaft, the interior of the
clamshell, and the bottom bearing / thrust-ball, which will benefit from a soak
to dissolve any hardened-up lube. Do not use anything that could deposit lint or
particulate into bearing.
wick out any remaining fluid, solvent, lube and then fill bearing with a light
motor oil. I use the '3-in-1 SAE-20
special-blend-motor-oil', (not the lighter Ďhouseholdí 3-in-1)
for this, and also for the upper bearing. This also benefits from an oil soak, a
wick-out with a clean cloth, and a refill.
once complete, reassemble and turn table upright. Gently turn motor manually for
a minute or two to get bearing seated and smooth. Start again if it is anything
but smooth and freely rotating.
Sounds much harder to do than it is. These are the basics--- keep a clean idler and platter-track, lube points cleaned and re-lubed. This is the start you want to give any 301/401.
One easy alignment trick is to run the table, at least 30 minutes on each speed, before disassembling, so as to clear a bright polished mark on the steps of the pulley. This will serve as an alignment key when setting the height position of the rotor shaft after lower-bearing service, as below.......
the bushing (#99) + thrustball
(#120) + felt washer (#100) + rivetted plate (#121) situation ... I really
couldnít be sure that the thrustball was free and unencumbered.
I went back yet again to the Garrard manual, which does in fact show, first, that the thrustball is held in place by a concentric spring assembly (#98) --and also, that those elements are on the outside of the aluminum 'clamshell' motor housing and thus pretty well contained for perpetuity by the four micro-rivets that hold the cadmium-plated 1x1" cover, (#121), onto the clamshell exterior.
outside of the motorís clamshell housing. So this little bearing setup is
under lockdown unless you go to the extent of drilling out the four
tiny rivets and then retrofitting some other fastener on reassembly......
a good procedure is to re-soak and hope to budge a reluctant thrustball, but
again only with something non-lethal to the finish of the bearing, washer, or
ball... Since I didn't think the elements were damaged, only slightly sticky, I
kept at it.
was not inclined to add any heavy solvent / penetrant, due to that felt washer,
which I couldnít be sure wouldnít dissolve entirely ----and so I went with a
few more oil-soaks and finally a Heated Soak. I just put the whole
lower-clamshell-w/bearing on the warm element of the kitchen range for an hour,
topped up with the bearing-assembly oil.
hurdle is that if you want any 'grip' on the thrustball as you prod it in hopes
of turning it, you can't use the same smooth slippery stuff (nylon stick, bamboo
stick) I'd been probing with. After
the saute was over, I got another bamboo kabob-stick and deliberately
hacked it unevenly across, so the exposed end was somewhat rough and mottled, so
as to have some grip. I cleaned up the cut a little with some light sandpaper,
and, got rid of any particulate .... and ... this was an all-around better
And pretty much an immediate success. Whatever was left at the 'rear' of the thrustpad, below the thrustball, just gave way. Just needed a little more traction.
Guess I should emphasize that all I've done is loosen up the thrustball ---- it doesn't come out of the rivetted enclosure, by design. That would be a more elaborate strip-down, to actually access the t-ball, bushing-shaft and felt washer.
I waited for a complete cool-down, then replaced surplus heated-oil with new clean oil and reassembled.....
Something Iíve learned to do by now, with a couple 301ís getting lower-bearing service here, is to Reassemble In An Upright Position. Which maintains all parts in vertical relation to each other and allows the least spillage of the motor-oil. It also slightly pressures that oil toward a complete saturation of the felt washer before it exits upwards, which is the goal.
Giving the motor-shaft a bit of gentle manual rotation during assembly also helps seat the rotor in the lower bearing, which can be a little more, or a little less time-consuming, depending on the original positioning of the elements involved. Keeping up a smooth turning motion not only helps the assembly process, but also serves as an early warning if something is amiss with the fit.
Itís also well worth mentioning that the final bolt tightness for the motor bolts should be done by tightening in the turntable-upright position, and testing / inspecting as you tighten. The vertical relationship of the parts on the rotor-shaft (ie pulley, eddy-disc, etc) and their partners (idler-wheel, brake-shoe, etc) changes slightly with bolts that are under or over-tightened. What should be judged in the adjustment is, first, the overall smoothness of the motor-shaft rotation, and second, the positioning of the eddy-current disc, as viewed on edge, in the center of the brake-shoe, which gives an idea of correct placement. If you have run the table on each speed prior to disassembly, you can also use the bright rings on the motor's stepped pulley to align to the idler. (This works better on the 60hz brass pulley than the nickel 50hz one which seems to keep a more intact finish.)
This takes a bit of trial and error, but--- if the Upper Motor Bolts have never been loosened or re-positioned, there is, at least, an existing starting mark for the final adjustment of the Lower Bolts.
Parts Numbers here are from the 1956 Ďtwo-starí Garrard 301 Schedule 1 Manual.
Thanks to Vinyl Engine for providing this online version of the manual, applicable to the greasebearing tables.