L eyland Oafs 80 Series was first seen at the Birmingham
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Motor Show last September. Born out of the Leyland Oaf merger, it comprises the Leyland T45 Roadtrain cab and chassis with the same Oaf engine and running gear that is used in the 95 Series.
With the tooling on the 145 cab being paid off, the 80 Series can offer a premium package at a lower price than the 95 Series. This vehicle is likely to be popular with fleets so we wasted no time in looking in detail at its servicing requirements — our roadtest model went straight into the service bay to be the subject of this month's workshop ways.
It has a Oaf charge-cooled 242kW (325hp) engine, an Eaton Twin Splitter gearbox and a Oaf single-reduction rear axle.
There are three levels of service — A, B, and C — and in normal use one is carried out every 25,000km. They are carried out in the sequence AA A B AA A C. Standard times are: A, six hours; B, 11 hours; and C, 12.5 hours. In addition there is an inspection-only P service which takes 2.95 hours.
The service was carried out in the manufacturer's demonstration fleet workshop by technician Tony Knowles who started with Oaf over 16 years ago. Knowles works on all the new vehicles as they enter the demo fleet.
by Colin Sowman Knowles starts his service in the cab with the usual checks on windscreen wipers, lights, gauges, electrical windows and glass. In addition the 80 Series is fitted with a (soon to be compulsory) Category One anti-lock braking system. The only check on the system is by the indicator light on the dashboard. Once the ignition is turned on the correct sequence is: light on, off, back on. It will then stay on until the vehicle speed exceeds approximately 12km/h (7mph). If it stays on above that speed there is a sensor fault on one of the wheels. Having completed the in-cab checks the vehicle is elevated by a mobile column lift and the oil drained while still hot. Knowles offers a tip for fleet workshops; the cab tilt bar and spanner on the 95 Series fits the sump plug on the 80 Series. It offers plenty of leverage and is always to hand during a service. For those who prefer normal sockets the plug size is 22mm and it has a copper sealing washer that should be replaced when it becomes deformed. The sump plug should be tightened to 80Nm (591bftl.
3 The oil filter should be changed at every service and is the next item to receive attention. It can be removed either by a strap wrench or by using a hexagonal key. The filter has a large capacity and should be loosened until oil runs down the outside then allowed to drain for a short while. Alternatively a hole can be punctured in the bottom to let the oil out before removal. To avoid the engine running without protection while the oil pump fills the large filter it should be primed with three litres of oil. The seal should also be smeared with lubricant to prevent sticking. Refit the filter hand tight and then tighten a further quarter of a turn using the hexagonal key or a strap wrench. When ready the sump can be filled with 24 litres (assuming you have filled the filter) of SHPD 10W/30 oil
The oil in the gearbox should be checked on the A service and changed on the B and C services. The level/filler plug, which takes a 27rrim spanner, is on the nearside of the gearbox and has a tapered thread. The drain plug is on the underside of the casing. Once drained the plug should be tightened to 6175Nm (45-55Ib1t). To refill the box requires 12.5 litres of SAE 90 oil and the level/filler plug should be tightened to 81-102Nm (6075lbft). There is a breather on top of the gearbox which must be kept clear. On the Daf single-reduction rear axle fitted to the 80 Series hub bearings are lubricated with differential oil. This should be changed on the B and C services; the level is checked on the A. The level/filler plug is on the front of the axle to the offside of the propshaft and is removed with the aid of a 12mm hexagonal key. To drain the oil remove the plug at the bottom of the diff housing. Refilling the aide will require 25 litres of 85W/140 (140 EP if a monograde is used). Again, check that the breather is clear. Knowles now moves from the back to the front of the vehicle attending to the greasing. There are two nipples on the rear spring hanger of each road spring and one on the front. As this is a new vehicle it was difficult to get grease through the front springhangers. To overcome this a bar is inserted between the bracket and the eye end — levering it downwards allows the grease to feed through. Each UJ on the propshaft has two nipples but only one need be used. Other greasing points are the top and bottom of the kingpins and the trackrod ends. The twin wedge brakes used on the 80 Series do not require greasing; nor does the clutch release bearing. A small hammer is used to tap all the major chassis, steering and clriveline components to check for loose bolts or hairline cracks in the castings. Knowles' philosophy is "if it is accessible, give it a tap." Items that must receive attention are U-bolts on the suspension; propshaft bolts; engine mountings; chassis brackets and steering components. Anti-roll bars should be given a good tug to check for play in the rubber bushes. Exhaust and air tank mountings should also be examined. There is a restriction indicator on the air intake trunking behind the cab. The filter should be removed and given a tap on the floor during the B and C service and renewed if necessary. The filter casing is quite low and the element only just clears the ground when being removed or fitted so it is wise to tackle this job while the vehicle is still on the lift. When refitting be sure to present a clean area towards the air inlet. Any muck that has collected in the water trap should be removed.
10 Asbestos-free brake linings
are fitted as standard in the 80 Series. The twin wedge brakes do not need attention as they feature automatic slack adjusters. Removal of the front brake drums is specified on the C service; the rear drums are only removed for relining or other work. The thickness of the brake linings is checked through holes in the backplate (a groove in the lining serves as a wear indicator). The vehicle can now be lowered and the column lifts removed.
The coolant filler lives under the front grille. The fluid should contain 33% ethylene glycol antifreeze all year round to act as an inhibitor, but if visiting very cold areas this can be boosted to 50%. Unlike the clutch fluid there is no call to drain and renew the coolant. The reservoir for the clutch fluid is at the top left of the under-grill area. At every C Service the fluid should be replaced with two litres of Dot 4. Knowles also finds that a squirt of penetrating oil on the grille catches is a good idea.
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There is a sediment trap in the fuel line behind the tank which should be cleaned out at every service, including the P. According to Knowles it is very efficient and blocked filters will only occur if the trap has not been properly cleaned. But don't rely on the thumbscrew at the bottom of the canister for cleaning, he says — instead remove the centre bolt, clean the inside of the trap and fill the bowl with diesel before reassembly. The cab is now tilted.
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The canister-type fuel filter is on the nearside of the engine and should be changed at every service. Remove the filter with a strap wrench and fill the new one with diesel before fitting hand tight. If the filter and sediment bowl are filled with diesel before fitting the hand primer can be used to draw the fuel up without undoing the bleed nipple. Any small amount of air in the system will self bleed. If the filter or sediment bowl are fitted dry it will be necessary to undo the bleed screw on top of the filter housing to bleed the system fully.
Fluid levels in the power steering reservoir must be checked on the A and B services using the dipstick beneath the rubber cover, With the engine stopped the fluid should be at the 'top' mark. On the C service the fluid should be replaced. To drain the old fluid out a pipe should be taken off the bottom of the steering box. At the same time the filter set beneath the large cap in the reservoir should be changed. Refill the system with two litres of Dexron II or ATE.
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General checks under the cab include the fan belts, which should move 1012mm when pressed crankshaft and water pump pulleys. Set on the top of the rocker box is a crankcase breather which should be cleaned during the B and C services. The element is removed and cleaned with fresh diesel, dipped in clean engine oil and the excess shaken off before refilling. The steering column's Ins, cab till ram ends and accelerator linkages should be greased at this point. Also, have a good look round for signs of leaking oil or water, loose air trunking and the like.
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Valve clearances should be checked on the B and C services. The rocker boxes have a rubber 0-ring seal that is reusable; a replacement is only needed if they are damaged. To adjust the clearances a 5mm hexagonal wrench and a 15mm ring spanner are required. Inlets and exhausts are all set at 0.5mm (0.020in).
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When jacking the cab back down it is important not to keep pumping once the locks have engaged. The ram in the tilt mechanism is double acting and if you over pump it will compress the cab onto its suspension, making the ride very hard. Knowles finds the best way to tell when the cab is home is to watch the gap between it and the mud wing (indicated). This gap should be about 35mm. It will briefly stop closing when jacking the cab down —the cab is then in position and will ride properly. The manual lock will not allow you to leave the cab in an unsecured state.
18 There is a sintered filter on the gearbox air feed which should be cleaned on the B and C services. This filter is in a small container set in the pipework near the top rear of the gearbox. To remove the filter take the top off — but do it carefully as there will be some air pressure to release first. Take the filter out and blow it out with an airline or wash in a degreasing bath and then refit, making sure the cover is done up air tight
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The 80 Series has an air dryer fitted as standard but Knowles recommends that the air tanks are still drained regularly. "It is the first indication that the dryer is not working properly when water comes out," he says. The dessicant container can be found at the rear of chassis between the lead-up ramps and should be changed every 12 months. A strap wrench is used to remove the filter, but the new one need only be done up hand tight
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On the B and C service the load-sensing valve should be checked and reset if necessary. Two air pressure gauges are connected; one on the inlet side of the valve, the other on to a rear brake chamber (the connectors are already fitted). The right pressures are listed on a plate in the cab. Inlet pressure, regulated by pressing the foot brake to the required degree, will be 5.52 bar (80psi) at the valve. Adjustments are made by altering the wire length between the valve and the axle.
The batteries are given a quick check before moving on to the front of the vehicle. Here the front of axle is lifted to check for lift in the kingpin and, on the A service, play in the wheel bearings. Steering ball joints are of the pre-loaded spring variety so it is not possible to check them without a special gauge as they will always have some movement. This can prove difficult at the annual inspection or at spot checks, says Knowles. The units are sealed for life.
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To complete the B service inspect the front wheel bearings. This entails removing the outer race and inspecting it for pitting on the rollers or race. On the C service the bearing must be stripped, cleaned, inspected and repacked with fresh grease. Finally as with all services, the ,wheel nuts are torqued. Those used to working on the Roadtrain should note that all the nuts have a right-hand thread and require 610Nm (450Ibft) of tightening.