Norfolk Garage

Is there a solution to this common problem, Richard ponders?

More workshop tales from Richard Hall

in general I don’t collect or deliver vehicles, but I have a small number of long-standing customers for whom an exception can be made. One of my customers lives out in the Fens and has two Land Rovers: a nice old Series III diesel and a Defender 200Tdi, both of which I have been looking after for eight or nine years now. Every year around the end of March I drive out to his farm, have a chat and a cup of tea, leave my car there and take the Defender home, service and MOT it, then swap it for the Series III and do the same to that. The two vehicles don’t cover a huge mileage between them and don’t normally give me a lot of bother apart from the usual electrical gremlins on the Series III, which always seems to need a few connectors cleaning up to get everything working well enough to keep the MOT tester happy.

This year my customer told me he had been having some problems with the Defender which had begun when he tipped in a gallon of diesel borrowed from a neighbour after thieves had drained the fuel tank overnight. It had started losing power and cutting out, which he put down to the borrowed fuel – a reasonable assumption as the vehicle had been fine before. So he replaced the dubious diesel with nice clean stuff from a garage, changed the fuel filter and took the old beast for a short drive round the block, and it seemed fine. However, before I departed he gave me a spare fuel filter just in case.

Within half a mile of leaving his house the engine started surging and spluttering. Fuel starvation without a doubt – if I eased off the throttle for a few seconds it would pick up and accelerate for a short time, then start to die again. It is amazing how busy the roads suddenly become when you are driving a vehicle with a mechanical problem. I put on the hazard flashers and limped slowly to the first lay-by with a long queue of vehicles building up behind me. I unscrewed the fuel filter and found it was only half full, which suggested either a blockage or air leak somewhere between the tank and filter, or a problem with the lift pump. It did not take long to establish that the lift pump had failed, with the priming lever waggling freely no matter how far I turned the crankshaft by hand.

As it happens, one of the first jobs I ever did on this vehicle was to replace the lift pump, and it had probably covered fewer than 10,000 miles since. That was disappointing, as was the fact that the vehicle would not drive even on the level with a failed lift pump. The Bosch VE injection pump used on the Tdi engines has a fair amount of suction on its own and I have had quite a few vehicles in for service where the owner had no idea the lift pump had failed until I changed the fuel filter, tried to bleed it and found that the priming lever on the pump was no longer connected to the pump internals. So, possibly what I had here was a combination of a failed pump and a filter partly clogged with debris from the bad diesel. One thing was certain – I would not be driving this Land Rover back to the workshop today. There aren’t many hills in Norfolk but there is one between my customer’s house and workshop, and no way would the vehicle make it up that hill.

I drove slowly and hesitantly back to his house and swapped the Defender for the Series III. It’s a lovely, sweet-running early (1972) example, with unusually supple suspension which I put down to the terrible Fenland back roads giving the springs a good workout. A Series vehicle on standard suspension actually rides quite well if everything is in good order, but on vehicles which don’t see much use, the spring leaves rust together and you end up with almost no spring action at all, which is not good for your spine. The temperature gauge was almost into the red although the engine itself was not running hot, and I made a mental note to replace the voltage stabiliser on the back of the speedometer while the vehicle was with me. What was I saying about electrical gremlins?

By the end of the next day the Series III was serviced, Mot’d and ready for another year of classic Land Rover fun (and now with a more or less accurate temperature gauge), so I drove it back to my customer after I had thrown a new 200Tdi lift pump and a few tools in the back. The whole issue of Tdi lift pumps has been bothering me for a while – I seem to change an awful lot of them and always with the same fault, which is that the link between the operating arm (which bears on the camshaft) and the diaphragm has snapped. I see the same fault in both 200Tdi and 300Tdi engines, even though the pump was relocated on the 300Tdi and bolts directly to the engine block rather than to a side cover plate as on the 200Tdi and earlier engines. These pumps always seem to be operating right at the upper limit of travel of the operating arm, and I can’t help thinking that this is putting more strain on the diaphragm linkage than is good for it.

Until the mid-1980s, four-cylinder Land Rover engines used an AC Delco lift pump which could be dismantled and repaired, with a ring of six screws holding the top cover to the pump body. These pumps bolted to a flat steel plate on the side of the block. Some time around 1986 the AC Delco pump was replaced with a sealed-

“It’s amazing how busy roads become when you have a mechanical problem”

for-life (in other words non-repairable) pump where the cover and body were crimped together. At the same time the flat steel mounting plate was replaced with a cast aluminium one, which was thicker than the steel one. To fit the later pump to the earlier mounting plate, Land Rover supplied a conversion kit (STC1190) consisting of a pump, a short piece of fuel hose, some hose clips, a length of metal tube, imperial and metric attachment bolts, and a plastic spacer block to fit between the pump and the mounting plate.

Given the intended purpose of this kit you would expect that the thickness of an early plate plus the spacer would equal the thickness of a late plate, but it doesn’t. An early plate plus spacer puts the pump significantly further away from the camshaft than a late plate without spacer. In fact, it puts the pump in exactly the right place, ensuring that the operating lever contacts the camshaft through the full 360 degrees of camshaft rotation, while avoiding undue stress on the linkage and allowing the priming lever to function properly.

You can fit the spacer between a late pump and late plate, but that puts the pump slightly too far out from the camshaft: it will work, but fuel flow may be slightly reduced as the operating lever is not always in contact with the camshaft. Having said that, I fitted the spacer to my customer’s 200Tdi and it seemed fine with no hint of fuel starvation under full throttle acceleration.

What is really needed is a spacer block about half the thickness of the one in the STC1190 kit, and I am looking at having some made up by a local company that specialises in laser-cut metal items. The spacer block does not need to be plastic on a diesel engine as there is no danger of heat transfer from the block boiling the fuel in the pump and causing vapour locking as might happen with a petrol engine. I find it hard to believe that Land Rover could have got the dimensions of the lift pump mounting wrong, but I have ruled out a problem with the lift pumps themselves as I am seeing the same linkage failures on pumps from several manufacturers. It has always struck me as rather odd that on these pumps, to get the priming lever to operate you usually have to rotate the engine by hand until the camshaft is in exactly the right position. That seems to be a consequence of the operating arm being right at the limit of its travel: the arm on these pumps has a longer throw than the priming lever.