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200TDI cambelt change


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What I did this afternoon. I have presented it in an easy to follow instructional format. ;)

Once the fan, cowl and hoses are removed you can see the job.


The first task is to remove the front crank damper (The bottom pulley to you and I). This is retained by a BIG bolt which is done up VERY tight. There is a proper special tool for restraining the damper while the nut is undone. I do not have one and took a chance by wedging the breaker bar against the chassis and spinning the engine on the starter motor. It works but it is NOT reccomended.


When the bolt is removed you are supposed to use a puller to remove the damper from the crank. I know that mine is not a tight fit and can be removed by hand. You should be VERY careful about using levers to remove it as the timing cover may become damaged (cracked).

The seal in the front cover runs on the pulley. Mine is very warn and should be replaced. You can see the ring of wear.


You can now remove all the bolts securing the front cover to the timing chest. It is best to keep these in order as they are different lengths and can be difficult to get back in the correct places. You will have to remove the water pump pulley too as some (shy) bolts hide behind it. Once ALL the nuts and bolts have been removed then VERY carefully remove the timing cover. Some parts of it are very thin and, if you force it, will break. If you need to use levers then be VERY gentle, damaging the mating faces may result in water ingress later - and the chance to repeat the job!

You will reveal:




This is the tensioner.


Once the rocker cover and the rockers thenselves have been removed you will reveal the pushrods. These are going to need replaceing!


Here are the push rods in an artistic arrangement. You can see that most of them are no longer the arrow straight items they should be. I will be replacing all of them. And this evening I will be drinking the contents of the box. ;)


On Saturday I will complete the job by putting it all back together with some shiney new bits. I will endevour to take some pictures of that too.



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Part 2, the putting back together bit...

see this thread for timing pins arrangements:

click here

First thing this morning I went out and fitted the new push rods, all 8. Here they are, the clean bits.


Next the rocker shaft. Be careful when fitting the rocker shaft that the back goes down first. This is where the oil way is and it can (and did) get hung up. The correct torque figure for the bolts is 30NM, the least my proper torque wrench will do. If, like me, you have had to do this stage you will need to re-set the tappets. I forgot to take a picture but it is quite straight forward using the "rule of 9", ie. number 1 rocking, you adjust number 8, number 3 rocking you adjust number 6 etc., always adding up to 9.


I had to do a lot of cleaning to find the timing mark on the cam pulley. When I did find it, it alligns with the arrow, I used sandbags make-up mirror to help see the mark and the arrow from the front as the radiator was in the way rather. The crank is in the correct position when the keyway is at 12 O'clock. I confirmed this by fishing about in the bellhousing wading plug hole with a 5mm drill bit and found the slot. The timing pump is locked by means of a drill bit too - before you fit either the pin or the belt you should loosen the three small bolts surrounding the large nut in the centre, this is for adjusting the fuel pump timing and getting it just so. The books say it is a 10mm hole but I found a 9.5mm drill bit to be a snug fit - perhaps the hole is 3/8"? See later picture for how and where is fits. With all the rotating parts in their correct position I fitted the belt and then the tensioner. Trying to fit the belt with the tensioner in position seemed to be a non starter. It is a fiddley job but persevere and you will work it out. There should be no slack between the crank pulley and the cam pulley or between the cam pulley and the fuel pump pulley.

You can see here the 9.5mm drill bit in position in the fuel pump.


Here you can see the timing arrow and dot alligned for the cam timing and also the hole where the drill bit fits into the fuel pump - it passes right through the pulley, timing case and into the pump body. Rather a poor photograph I am afraid but you get the picture (pun :o )


Once the belt is on and tension applied (see below) the engine must be rotated two revolutions - two revs of the crank, one revolution of the cam and pump obviously. Remember to remove any timing pins (drill bits) first!


Refit the fuel pump timing pin. Check that all the marks still line up and then loosen the tensioner and re-tension to 19 NM for a new belt or 17NM for a used one. You need to use a deflection type torque wrench (see picture) or a dial type. The correct torque for the tensioner clamp bolt is 45NM.

Tighten the three bolts around the center of the fuel pump pulley. This will set the injector timing. Remove the drill bit. I like to re-set the injector timing after a couple of thousand miles just to be sure and to compensate for any stretch in the belt. This can be done easily through the small cover in the timing chest cover. The job is pretty much done now - at least the technical bit.

Setting the belt tension.


Always be sure that the timing chest is well sealed when re-fitting. I use Hylomar non setting sealant or similar. You do NOT want water in here as it will cause the belt to fail in no time flat. If you are like me you can now enjoy a Mensa style test trying to work out which bolt goes in which hole in the timing chest - or you could have kept them in order in the first place! Personaly I relish the challenge.

I decided to leave the original dust seal in the front cover as it seems to be doing it's job for now and I plan to have it all apart again later to get the injector pump tested. I will make proper arangements then to repair the seal and it's land. Anyone got any details of the shim sleeves you can get for this job?


That just about concludes my idiot's guide to replacing a broken cam belt in the real world, not in a spotlessly clean workshop in Sparkford. I feel sure that I must have forgotten some important fact, feel free to add anything relevant - or even to ask questionsa if my explanation is not sufficient.

I am waiting for the battery to charge now so that I can see if it starts - and to confirm that this guide is worth the paper it is not written on. Time to find some lunch I guess.


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Have you tested the engine for compression? just that as you have a vast amount of bent pushrods this is normally caused by the valves being shoved-back by the piston by force, thereby normally bending the heads of the valves <_<

It seems OK thanks. I have seen a lot (well, several) of Tdi belt failiours and I have yet to see one do more than superficial damage. The valves in a Tdi are vertical in the head and so hit the pistons square on. The valve stems are very hard and resistant to bending - unlike the pushrods which are made from brie... I suspect for a very good reason! FWIW, 300 Tdis apparently have deliberatly weak rockers so that they break in such circumstances. Anyway, it runs now and I am off to Sussex in it in a couple of hours, I will report back if there are further problems.


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