We had Guy’s with the 280 Rolls and Seddon Atkinsons with 265’s, they never had any real engine trouble but those bloomin group hub reduction axles on the Sed Atkis was a regular suspend tow job, unless the driver spotted the seals leaking before the bearings collapsed in the hub. We never had any more and specified Rockwell axles on all the later ones.
I am still involved almost daily in keeping some of this antique machinery going. Nearly all of it is in buses these days, but it used not to be the case. The oldest currently is a 1935 Leyland with an overhead camshaft 8.6 diesel which has a split gear and spring arrangement to compensate for gasket thickness.This has a one piece head which warps, and a timing chain - which stretches- from the crank to an idler gear. Like most Leyland engines getting either manifold off is a recipe for a few choice words. The 600 was probably the best engine Leyland ever made. Apart from head gaskets the only failing I can think of was leaks from the adapter plate behind the timing case gears if a new compressor had been fitted. The Albion hub reduction axle suffered from the same planet gear wear that got the Seddon Atkinson axle such a bad name, it was just not such a regular occurrence. However the flimsy bearing locknut tab washer was about as much use as a piece of Coke can.
I suppose AEC are the easiest to service and repair even allowing for the coolant elbows corroding to the securing bolts. Years ago smash it with a hammer and renew it - nowadays it has got to come off intact however long it takes! These days I mark the fuel pump flywheel with ‘LP’ to indicate when it is on the back of the cam and works properly. With no easy way of rotating the engine however finding a starting point for tappet adjustment with the siamesed ports making identification just that bit harder, is still the bugbear it always was. The common head gasket renewal is straightforward except for the time required to clean around the base of the head studs and the now common issue of having to renew corroded studs. Unless the vehicle had Lockheed brakes the rest of the chassis was as good as the engine. The six speed overdrive gearbox could be taken apart with little more than a hammer and spanners. The only real pain was the clutch hydraulic cylinders in tilt cab models.
Gardner were always a doddle to service, providing you could get at the timing chain adjuster this was only a few minutes work. The worst servicing job on the LX series was getting the back and top of the governor housing off in order to adjust the rack. On the LW with no housing it was so much easier. A block change on an 8 cylinder would require umpteen hands to hold the piston ring clamps in place while it was lowered over the top. Being able to decompress the engine just made rotating it so much easier. Hanging all the bits back on after an overhaul was incredibly time consuming, taking care not to mix up the 5/16" set screws, some of which were BSF and some Whitworth thread; the worst bit of the lot being fitting the governor housing oil drain O ring.
■■■■■■■ 12 litre and 14 sixes were probably the worst to service. The oil filters if of the element type could be mounted remotely anywhere on the chassis, covered in filth and awkward to dismantle. The spin-on ones fitted later could break your filter strap sometimes. Turning the engine over to adjust the tappets and injectors was just plain awkward as was the task of removing the paint from the accessory drive pulley so that you could read the markings. Torquing down a 12 litre head to 400 lbft in a fixed cab was certainly not for the faint hearted. Even after filling up the fuel filter getting the thing to run needed virtually new batteries. The fuel pipes to the cylinder head or elsewhere were in danger of twisting off as soon as look at them unless great care was taken … and even that was no guarantee. If the top coolant rail was disturbed for any reason then it leaked when refitted; with or without being spotless and having new O rings fitted. Fortunately the big engines did not suffer from the leaking timing case issues that plagued the B and C series engines.
Polly Perkins 6.354 turbo just ate oil coolers which meant half a day flushing the rad out. Probably top of my list for recalled nightmares was renewing the V8 lift pump - I just never had the knack.