1.9TD Crankshaft Pulley Bolt Snapped.

AndersDK · Post by **AndersDK** » 29 Nov 2003, 09:06

Pete -
It MAY be because right behind the pulley - you have the cambelt & it's crank drive cog located. If the pulley disappears - so does any hold of the cambelt [;)]
With a little luck - we may fool DaveBurns to have an extra peep in the right book - just to be sure this insane torque is correct ?
What do you think Dave ?
The bolt is torqued the same direction as the pulley turns with the running engine - and on top of that - the bolt thread is secured with Locktite.
In view of the extra strain put on to the threads - with a relatively frequent removal for cambelt replacement - how come this bolt must be that tight ?

sooty · Post by **sooty** » 30 Nov 2003, 01:11

I hope I'm not the one to have your car when you sell it, with its pulley bolt locked with 'bearing fit' compound. I've used the Loctite version and once its applied, the only way to break it or any of the same high strength is to warm the part with a welding torch.
I would have thought a 'thread lock' would have been ok, being a low/medium strength.
Sooty

David W · Post by **David W** » 30 Nov 2003, 04:15

Sooty,
If you are referring to the car I discussed as the main topic of this thread you are quite right...it's a bodge and I would never advise anyone to buy it.
But what do you do when the proper resolution was a new crankshaft from Citroen? The owner was paying for this work to be carried out and the repair would have cost more than the value of the car.
As it happens the bearing fit worked and if you were the owner I think you'd be pleased to get away with it.
That was why I made the point we will probably not risk doing the timing belt again, by the time it is likely to snap the car will be down to scrap value anyway....if not already in the breakers due to age/mileage.
As a matter of interest a new crankshaft bolt from Citroen is only £1-80 and it comes with the correct thread-lok substance already on the thread. Given the problems of a snapped bolt it might be worth thinking about a new one every time the timing belt is changed....and not using extra fluid of any type.
David

oilyspanner · Post by **oilyspanner** » 30 Nov 2003, 20:33

I have encounterd a couple of TD motors where the bolt had come loose! splitting the timing belt pulley amd chewing up the crank nose and keyway, I believe the bolt is a Stretch bolt and should be replaced at belt change time, though short od main dealer types I dont think anyone ever does, I take my hat off to David for successfully drilling out the old one.
Stewart

Dave Burns · Post by **Dave Burns** » 01 Dec 2003, 00:47

Anders, first stage tighten to 30 lbf ft, second stage tighten a further 60 degrees, thats just one flat of the bolt head further so is not particularly tight at all, certainly nothing like a head bolt, now they are well tight 44lbf ft and a further 220 degrees.
I suspect most people will severely overtighten the crank pulley bolts making them the bugger that they are to get off.
Dave

AndersDK · Post by **AndersDK** » 01 Dec 2003, 01:01

Thanks Dave -
Agree this torque in no way is dramatic. Must be the issue cracking the cold Locktite then - which then points back to the previous comment that the engine should be run hot (if possible) to soften the Locktite.
And that's exactly my last experience on my '89 BX16 this spring when removing the bolt. Did it on cold engine - and it was indeed a bugger to crack - similar to the hub nut.

mg46783 · Post by **mg46783** » 02 Dec 2003, 04:48

Hi... on the subject of "why" the bolt is so tight.. I may be wrong, but I seem to remember something about oil presure - and the No1 bearng on the crank... ??? cant rmember the full story !! I will - at about 4 in the morning !
mike