by Tim Williams » Mon Jul 31, 2017 11:19 am
As has been correctly identified that first photo is ex Lewis Bros No 60, in a mechanical sense it was a twin to No 55. Both coaches built up from Leyland Hippo and other parts, with very heavy 5 or 6 speed constant mesh gearboxes, both being quite difficult to drive. The old 680 must have had a large flywheel which results in the engines revs going up and down slowly and therefore slow but accurate timing of the double clutch gear-changes was vital - the fact that the gearbox was mounted at the rear, between the rear axle and the engine with sometimes an inoperative rev counter, made the task even more difficult - not to mention the reverse pattern to the gears and a very imprecise shift mechanism.
Additionally because the heavy nature of that gearbox, it was normal to select second gear when just stopping at traffic lights, ready for a reasonably prompt departure on green, but occasionally the hydraulics in the clutch would fail and you would move off - even on idle, with the clutch pedal fully depressed and not being physically able to shift the gear lever to neutral! This happened to me crossing Magill Road in Adelaide - fortunately I was first in line at the lights, when on red lights, I just took off slowly, on red lights, with traffic, screaming to a halt on either side. Once moving with a little feathering of the accelerator, it became possible to get the bus out of gear. I think these two coaches (55 and 60) had Holden slave cylinders which just were not up to the task and holding the buses in gear, which the clutch depressed, was too much for them. The alternative was to wait at the lights in neutral and depress the clutch and start selecting second, which would take quite a while for the revs to synchronise and allow complete selection of the gear - holding up traffic the the process.