Recovery scene
Whilst being more for show than hard work, LHG620X the Leyland Cruiser recovery vehicle has to do its bit on the rare and infrequent occasion that demands it.
Failure of the coach's nearside hub-reduction gear mechanism meant that it was not sensible to drive it any further. Otherwise a total loss of drive and further damage to the axle would have been the probable result. Therefore the the Cruiser was summoned to drag the errant Leyland Tiger back to the company's depot for further investigation.
A couple of weeks ago whilst I was driving PUI9321 I experienced an irregular dragging sensation and a noise akin to something metal being wrapped around the propshaft, as I moved away from a bus stop. Nothing further was heard or felt during the rest of the school contract journey and return to base. I spent time whilst driving mulling-over what could be the cause, without reaching a firm conclusion. However when I drove the coach again in the afternoon I realised that the back axle was "singing" more than usual. Upon my return I discussed this with our mechanic and when he drove it the next day he was able to agree with my prognosis of "one of the hubs is in trouble". Due to operational requirements the coach had to continue be used on a near daily basis. Things were getting noisier at the back end when I drove it again yesterday and sure enough, this morning the noise changed to a much heavier clonking.
After recovery the hub was stripped down and the true extent of the damage was revealed. The four planetary gears are housed in a cage and run on needle-roller bearings which are in turn running on a large pin. These pins wear with age, the wear becomes much accelerated once the hardening is worn through, then the bearings have too much room to move about and fail. The resultant disintegration allows the bearing components to become "grist to the mill" of the reduction gears which in turn become damaged and or siezed which adds even more metal fragments able to circulate in the hub mechanism. We were unable to remove the gear cage due to damage of the hub casing teeth and the reduction gears were all damaged with chunks missing from their teeth. One was completely jammed and there were no remaining bearings to speak of. The hub casing contained a fair amount of a metallic paste formed of well-ground pieces of metal and the lubricating oil ! The remedy to enable the vehicle to be returned to service on Monday was to rob a complete hub assembly from a sister vehicle that is presently parked-up out of service. As a precaution the axle oil was also changed after cleaning the area of the main axle exposed when the hub was removed.
Recovery scene
Whilst being more for show than hard work, LHG620X the Leyland Cruiser recovery vehicle has to do its bit on the rare and infrequent occasion that demands it.
Failure of the coach's nearside hub-reduction gear mechanism meant that it was not sensible to drive it any further. Otherwise a total loss of drive and further damage to the axle would have been the probable result. Therefore the the Cruiser was summoned to drag the errant Leyland Tiger back to the company's depot for further investigation.
A couple of weeks ago whilst I was driving PUI9321 I experienced an irregular dragging sensation and a noise akin to something metal being wrapped around the propshaft, as I moved away from a bus stop. Nothing further was heard or felt during the rest of the school contract journey and return to base. I spent time whilst driving mulling-over what could be the cause, without reaching a firm conclusion. However when I drove the coach again in the afternoon I realised that the back axle was "singing" more than usual. Upon my return I discussed this with our mechanic and when he drove it the next day he was able to agree with my prognosis of "one of the hubs is in trouble". Due to operational requirements the coach had to continue be used on a near daily basis. Things were getting noisier at the back end when I drove it again yesterday and sure enough, this morning the noise changed to a much heavier clonking.
After recovery the hub was stripped down and the true extent of the damage was revealed. The four planetary gears are housed in a cage and run on needle-roller bearings which are in turn running on a large pin. These pins wear with age, the wear becomes much accelerated once the hardening is worn through, then the bearings have too much room to move about and fail. The resultant disintegration allows the bearing components to become "grist to the mill" of the reduction gears which in turn become damaged and or siezed which adds even more metal fragments able to circulate in the hub mechanism. We were unable to remove the gear cage due to damage of the hub casing teeth and the reduction gears were all damaged with chunks missing from their teeth. One was completely jammed and there were no remaining bearings to speak of. The hub casing contained a fair amount of a metallic paste formed of well-ground pieces of metal and the lubricating oil ! The remedy to enable the vehicle to be returned to service on Monday was to rob a complete hub assembly from a sister vehicle that is presently parked-up out of service. As a precaution the axle oil was also changed after cleaning the area of the main axle exposed when the hub was removed.