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300TDI timing belt replacement


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#1 white90

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Posted 02 February 2008 - 09:47 PM

As the topic description says - this is a service interval replacement only - any timing problems will need other work and use of a timing setting pin. Belt change interval for this engine is every 72,000 miles or six years under normal use. Of course - if you nail it to Tesco and back every Saturday, then the demanding driving and engine performance required to negotiate the car park means that you might be wise to change the belt more frequently than this! :D In the real world, you only need a 10mm drill bit and a bit of Tippex to set the timing. The timing belt on it's own can be replaced, but this isn't wise - belt failure due to idler or tensioner wheel wear won't trash your engine - usually it just bends push rods and has been known to snap rockers too, although the latter is rare. Far better is to buy a Timing belt kit - 60 - odd quid, and then the crank front oil seal, and timing cover seal. This is the kit and two seals.

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This your engine! :D (well, if you have a Disco, that is)

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Drain the cooling system down a bit - you need to remove a couple of hoses, and some coolant loss is inevitable. Remove the top of the fan shroud - held by a clip on the left side.

The viscous fan is left hand thread (undo clockwise) a 32mm water pump spanner will release it. Sometimes a sharp whack with a hammer is needed to break the thread.

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The fan will unscrew by hand and then come out the top of the fan shroud. In order for the main shroud to come off, you need to remove the top radiator hose completely, and also the bottom radiator hose where it connects to the pump, also the heater hose that branches off of it.
Tuck the bottom hose out of the way by the side of the alternator.

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Also the connecting pipe for the top intercooler pipe.

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There are two clips that hold the shroud to the radiator - remove them and then the main fan shroud will twist and come out.

Not essential, but to create more room to work on the crank pulley that's bound to be siezed solid - I remove the idler wheel and PAS pump wheel. So while the belts are on and still tensioned - slacken the 4 bolts that hold each wheel on.

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Now to undo the crank bolt the way that isn't recommended. If you don't like to do it the way described here, then you will need to obtain the correct locking pin for the flywheel.

Anyway - remove fuel cut-off switch wire from the rear of the injector pump.

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Place 27mm socket on a breaker bar, so that the bar is up against the underside of the chassis rail on the drivers side.

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Rest the bonnet down, and then briefly flick the ignition, so that the engine only has time to turn once or twice. There should be a bang and the crankshaft bolt will have come undone. Open the bonnet, and check - you may have to do this more than once.

Release the power steering and main belt by slackening the tensioner (Air Con pump), and then removing it.

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Main fan belt is an automatic tensioner, so 15mm socket and lever to the left to release tension, then to give you a bit more room to work - undo the 15mm nut and remove the tensioner completely.

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Remove idler wheel.

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Bypass hose.

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The crankshaft pulley is solid, as expected, so I have a DIY crank pulley puller - very simple device, but works every time.

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Unscrew the crank bolt a few turns, put the 27mm socket on it, then as the two m8 bolts are tightened a bit of a time each, the pulley gets drawn off the end of the crank.
In position

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A bit time consuming, but there's not really an effective way of doing it any quicker.

Pulley off, and now the timing outer cover can be removed.

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The bolts that hold the cover on are various lengths, and a simple bolt pattern card will save time.

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Replace the cranshaft bolt and rotate the engine clockwise until the crankshaft woodruff key is in the 12'o'clock position.

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And the camshaft mark is in line with the casting like this.

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A 9/8.5mm drill bit will then slide through the hole in the injector pump sprocket (roughly 11'o'clock position)
Picture has failed I'm afraid.
In this situation the engine is set with No1 piston at Top Dead Centre.

The tensioner and idler wheel are seperate, but in order to remove the tensioner, you need to release the idler wheel as well. The idler wheel is held in place by 15nut on a stud, and the tensioner is held by an 8mm socket head bolt. Remove the nut and bolt and the assembly will come off.

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The belt is now loose and can be removed and discarded.
There's a new crankshaft sprocket in the kit, so remove the old one, carefully lever the oil seal out taking care not to damage the alloy casing. Clean and then fit a new oil seal, lightly grease the crankshaft then gently tap the new sprocket into place.

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There's a new stud, nut, and bolt, comes with the kit. Threadlock the stud and then screw it in with a pair of mole grips.

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New tensioner and idler wheel - this is how they fit together, make sure they are like this when on the vehicle.

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Place the tensioner on first, then the idler - do the 15mm nut up, but leave the socket head bolt off for now. If you have got it right, the tensioner assembly should be free to pivot behind the idler. Feed the new timing belt on - keeping tension between the crankshaft and camshaft sprokets on the right. Any slack should only be btween the injector pump and crankshaft sprockets on the left - where the tensioner will take it up.
New bolt has thread lock already on it, once the belt is over the sprockets, put the bolt in but do not tighten fully yet..



Timing belts are not at all like fan belts, they don't need to be stretched any more than is sufficient to prevent them vibrating or coming off the sprockets. A belt that is too tight will howl and fail prematurely, a belt that's too slack is going to vibrate and either fail prematurely or come off one of the sprockets.
Method of tensioning is simple. The end of a 1/2 drive bar on a torque wrench is used to tension the belt at 15 Nm, and while held at this tension, the socket bolt is tightened.
Remove the timing pin and rotate the engine two turns of the crank, re-check belt tension, and the cover is ready to be replaced.

Tensioning the belt.

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Check the timing is still ok locking pin should slide back in the injector pump sprocket, marks on the cam sprocket should align, and woodruff key on the crank should be at 12'o'clock.

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The timing cover seal also needs to be replaced, and the rubber dust inside cleaned off too.
A hammer and screwdriver can be used to knock the old seal out, and after cleaning the cover, press a new seal in.

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That's it really - new gasket on the timing cover, and don't forget to tighten the crank bolt to the specified torque - 80Nm and then 90dg. Top up the cooling system, pray there's no bolts or nuts left over, and that should be it for a few more thousand miles.


Les.
Tony


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#2 JimAttrill

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Posted 12 March 2008 - 06:32 PM

L/R special tool if you so require one Posted Image
1996 Defender 300Tdi 110 csw




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