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Replacing a series lift pump.


Les Henson

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If you are fortunate enough to own a series motor, then every 20-years or so, you might find that you have to change the fuel lift pump. The method is exactly the same for petrol and diesel - the latter having one more pipe. The pump is tucked mid-way down the drivers side of the engine, and there's a nest of wires, fuel pipes, and the air filter hose maikng replacing it a bit fiddly. This is one of those jobs that puts a lot of scratches and scrapes on your knuckles. wrists, and forearms. The first picture looks like there's a new pump already fitted, but that's because there is! The camera played-up, and I had to take what is really the last picture, and use it as the first, so the lack of oil and general filth, is just an illusion :D

Anyway - buried down the side of the engine is a filthy, knackered, lift pump.

Remove the oil-bath filter and inlet pipe to improve access, cable tie wiring etc out of the way.

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This vehicle is a 2.25 diesel, so although there are 2-connections, there are three pipes. A petrol will have just the two. Inlet is 13mm ( or 1/2 inch), undo it and tuck it out of the way as best you can.

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The outlet side of the pump has two pipes on a diesel (one on a petrol), one will go to the injector pump, and the other will return to the filter housing.

The type of bolt here is known as a 'banjo bolt' (19mm/3/4") - it retains a collar with more than one outlet, and there will be two fibre or copper washers to effect a seal. These bolts are hollow and a fine thread, there's no need to tighten then excessively - as they also screw into an alloy thread - it's easy to strip one and ruin the alloy thread too.

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Once the pipes have been disconnected, the pump itself is held to an adaptor plate - usually by two bolts (or in this case) two studs and nuts, that is in turn, bolted to the side of the engine block.

The height of the vehicle and the depth of the pump relative to the engine, makes this awkward to do. Something to stand on makes it a lot easier.

Old and new:-

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The new pump may not look the same as the old, some after-market pumps are sealed units, and although looking different, do the same job.

With the pump removed, you can see the adapter plate, the clutch flexi pipe connection (on th eleft), and the hole that the foot of the pump sits in. There will be some oil loss through the hole, but not much. Remove the old gasket and clean the mating face of the plate. You can just see the off-set lobe of the cam that drives the pump through the hole.

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Getting at the two bolts (or nuts), that hold the pump to the block is fiddly enough, so unless there are two studs sticking out of the adapter plate - just glue the pump gasket to the pump, with anything - thick grease, RTV sealant, nail varnish, Mr sheen, cream cheese - anything. There's no way you are going to be able to hold the new gasket in position, AND put the new pump on!

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When fitting the new pump, make sure the leg is on top of the cam, the flat face on the bottom is what bears on the lobe. Introduce the pump 'high' in the hole to make sure of this.

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Once the pipes etc are connected, a diesel would need to be bled, there are two bleed screws on th eside of the injector pump, undo this one a couple of turns and then operate the lever on the bottom of the lift pump until a bubble-free jet of diesel can be seen. That's it - apart from the scratches you now have on your wrist, your engine will purr like a kitten once again! :lol:

For those of you that have a v8 engine, there are three things you need to do that are different.

(1) Take the engine out and chuck it in the bin.

(2) Fit a diesel

(3) finally realise what happiness is. :D

Les. :P

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Les, can you still buy replacement one way valves for the servicable type pumps ? These can be used as replacements for the ones that eventually disintegrate in the 300TDI brake vacuum pumps. I have always used old ones removed from the many 2 1/4 litre fuel pumps I have lying around.

Bill.

Les 'Haynes' Henson,

thx for another excellent thread. Is it possible to install the pump incorrectly so that the arm does not sit correctly on the lobe? If so, then this just might be the problem on my old series as i have fuel flow problems with a new pump.

Nigel

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Bill - the whole pump was only £11.50, so I just replaced the complete unit.

Nigel - don't know really. I would have thought that the arm would jam if it was under the cam, or maybe not work at all. The foot of the pump has to be pushed upwards, and it's own spring helps return it. If the foot was under the cam, then it would try to push it downwards instead. Maybe your problem is in the tank/pick-up pipe??

Andy - any kind of herb will wreck your engine - must be plain fat-free variety :P

Les. :)

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For those of you that have a v8 engine, there are three things you need to do that are different.

Les Hayneson. :P

the lift pump (I would call it the fuel pump?) is fitted to the timing cover on early engines as went into the P5, P6 and the earliest of Range Rovers.

The SD1 timing cover has this area blanked off as part of the casting although I would guess if one really insisted, one could cut a hole and fit the pump there (like the series engines, it takes it "drive" off the camshaft but you need to be sure it has the drive cam fitted on the camshaft). In case you were wondering how those engines run, they have an electric fuel pump.

If you wanted to convert early engine to use an electric fuel pump, whip off the mechanical pump and a fit a cover i.e. plate with two holes, cut to the right size, over the hole.

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Andy - any kind of herb will wreck your engine - must be plain fat-free variety

and i thought herbs where healthy.

ive heard of fuel pumps being installed 'under' the cam on other engines. never seemed possible when ive done the job though.

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  • 5 years later...

Hi guys. some newbie questions for you...

I think i have some problem with the lift pump

My S3 is 2.25 petrol+lpg

in the morning regardless of the weather it starts at first try on lpg,

but when i try to start in on petrol it doesn't (even if i leave it on petrol from the night)

While driving i can switch form petrol to lpg and lpg to petrol

Last night i checked my lift pump and saw it was covered with oil...

is that the problem?

little help needed

thanks

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