kieran .
45,000 miles is way to far before changing 300tdi timing belt, should be done 20,000 i think in reality .
i have changed mine twice in 12,000 miles and the previous belt had lost 6mm width of belt in 12k miles , i had to do something about it and find out the real source of the problem, which i did too !!
the modification kits to cure timing belt wear dont actually guarantee curing the problem .
all they seem to do is add a flanged crank gear and a different idler pulley in an attempt to stop the belt walking forward , but the belt walks OFF the front of the injector pump gear and if you dont align this gear properly all will probably be in vain fitting a modification kit .
basically what you need to look at is the injector pump bracket on its rear that bolts it to the engine , there is a bump of material on the bracket that makes the injector pump push away from the cylinder block at its rear, thus the belt walks forward and is only stopped from coming off by the timing cover .
i found my pump gear was running out by 0.015" , ie the gear was
0.015" farther away from the rear timing cover when it was measured at the most outboard area of travel compared to 180degs opposite side .
i filed the bump off the pump bracket , this allowed the pump to sit square on the rear timing cover and not pushed away from engine . with no belt installed i tightened the bolts from the pump bracket to engine and also from bracket to injector pump.
after fitting new timing belt i checked the alignment of pump gear again with a dial indicator and it was then running true .
if you do check and adjust this make sure you measure carefully because there is almost 0.120" thou endfloat on the injector pump shaft and if you rotate engine the gear needs to be sat in its seated position or youl get false readings .
there is a lower belt torque now also, i think it was 9ft/lbs i used , torque it once, slacken off belt tensioner and torque again is best option .
although landrover now say only torque up the belt tension once and be done .
you can drill an 8/10mm hole at top of timing cover , facing in line with front of belt, and then can measure depth in hole of belt to see if belt moves forward, the timing cover will have rubbing marks on it so is easy to work out where to drill hole , no need to plug hole because its running dry inside the iming belt housing , although a rubber grommet is easy to buy and fit . .
in 2500miles mine hasnt moved so far .
bear in mind that pump timing will alter very slightly every time you change a timing belt, and full load fuel metering may need adjusting a little , especially if performance drops off .
when you drive them everyday you will notice any change in performance easily .
in fact i had to unscrew my full load metering adjustment on rear of injector pump by a fair amount after installing new belt .
cheers , ian