I must admit to being initially surprised by all these tales of glued-up garrard decks, as my main extensive experiences of these (from RC88 to SL95B to GT55 with many different ones in between) had been mainly in the 70's when they weren't very old or were new. HOWEVER, I was very kindly donated a very clean AP76 to fettle a month or so ago. I don't know if the deck plate stamping is different (to accommodate the slightly smaller top platter on the SL72B [and older AP75?] which is set lower and enables the arm to look more or less parallel when playing one record), but apart from the induction motor and inverted "single point" bearing on the AP76 - rather than a captive ball race - the mechanicals are broadly the same, as is the tonearm.
I couldn't believe how some of the pivots on the mechanism had become practically solid with disuse. The trip pawl on the main cam was solid and could barely be moved with my fingers and the pivoted and sprung lever assembly on the speed change mechanism was the same (no wonder there's an AP76 on eBay UK with a piece of wood grafted on where the plastic speed/size adjuster used to be.....).
Sadly for some of you less mechanically minded, these parts really do have to come off the deck for thorough de-greasing. I used some solvent cleaner in the first instance on the speed change mech (watch the correct fitting of the "spring" when re-assembling) and then a drop of hypoid gear oil, which once worked in, is now fine and precise on operation. The idler wasn't quite straight and true on its mount (like this from new I reckon) and careful bending back straight enabled the idler height adjustment to be set more centrally.
The main issue was the trip pawl assembly. Since this isn't as accessible as on the autoslim derived models, the cam has got to come off and without dismantling too much, this can be done with care. My deck seemed to be fine on the sliding parts, the grease still pliable, but this may be different in hotter and drier climates obviously. Getting the pawl levers off the cam was very tricky on my sample, but careful work and some oil to soften the "adhesive" worked wonders. On de-greasing and reassembling these parts, I did put a drop of clock-oil on the pawl pivot, obviously leaving the sliding parts totally clean and dry. Once these bits passed the "tambourine test" - shaking the cam should have these parts jangling around freely - I reassembled the mech.
As for the main bearing and drive, I thoroughly soaked the bronze bushes with fine oil (the motor was free but dry as a bone), lubed the idler bearing, the rubber of which was still supple with no flats and the bearing bushes/sleeves got a good dose of hypoid EP80 as well as some LM grease between them. A drop of EP80 on the top of the spindle (flat across on this model) and the platter was re-fitted and ready to go. Unlike my original AP76, the platter on this doesn't rock too much (hardly at all with the grease between the bearing bushes/sleeves) and barely shows any up/down movement at its edge when running - some do for whatever reason.
The exit signal cables and mains lead was as folllows - three core UK mains wiring, the green earth lead connected to a nearby chassis point and the tonearm earth wire (black) kept disconnected from the four signal wires (sometimes the chassis is earthed via a wire link to a signal screen, but this causes more hum quite often I found). Some Van Damme "Pro Patch" mic cable and Neutrik-Rean phono plugs (outer screen of cable connected to the phono screen at plug only and only the four inner connectors used for signal. The result for me is no hum and better sonics.
I put an Audio Technica AT120E in the C2 carrier (including necessary "wedge" and sat back to listen... The "sound" from this combination is staggeringly good for a lowish mass and rather flimsy arm, slightly rattly bearings (I can't adjust the horizontal bearing any more than factory setting), the arm handling 1.5g tracking weight in its stride (I checked this with an Ortofon gauge). It's not going to give the audiophile heavyweights much to worry about, but the basic soundfield is well developed, with good width and depth in pretty correct proportion, rumble is very low on this one (with smaller speakers anyway) and I played many an LP over Christmas with it in my second system..
I don't mean to hi-jack the thread, honestly - but I hope this gives some of you and the OP in particular, some insight as to how good these decks can be and that it's well worth spending some time restoring them and fitting a modern sympathetic cartridge - The 75, 95 and Z100 arms may need a lower compliance cartridge, although a Stanton 681EEE sounded fab in an SL95B I once owned).
One final thing, please be careful in how the cueing height is adjusted (the little screw inset into the black lifting platform that raises and lowers - not the screw on the arm itself). Mine was set so the arm lifted off the record a fair way on auto and then raised even higher when it reached the arm-rest. careful adjustment of this little inset screw seems to have sorted this out, the main adjustment on the spring loaded screw on the arm being ok for manual and auto settings.