1.9TD Crankshaft Pulley Bolt Snapped.

David W · Post by **David W** » 08 Jan 2003, 14:45

Anyone ever snapped a crank pulley bolt on a 1.9TD? How easily did the remains come out??
I've just done this undoing one on a '93 Xantia. Bolt was well rusted, possibly from vehicle spending years in a coastal environment. Also it seemed to be coated with something like bearing fit (not loctite).
It's snapped with all the threaded section in the nose of the crank. Just ordered an expensive set of stud removers and hope to give it a go tomorrow.
David

rg · Post by rg » 08 Jan 2003, 16:49

David,
I'm sure that I,ve seen some Loctite-manufactured gunge that releases bearing-fit. Might be worth asking.
I have also seen left-handed drillbits advertised. It sounds like something that you would ask an apprentice to get from the stores for his "initiation" ("left-handed screwdriver", "a long stand", "a fallopian tube"). In these circumstances, anything might help.
rg

David W · Post by **David W** » 08 Jan 2003, 17:13

Rob,
I've had a cheap Sykes screw-out extractor set for years, you know the sort that breaks off in the stud and is too hard to drill! I know this bolt is going to be too tight for those so I'm not going to even try.
Just had a parcel arrive from Snap-On with a pro extractor set plus some extra removal bits, a "Cobalt" left handed drill and cutting oil. I chose this particular extractor set because the agri-engineers across the road use one and say it is the only kit that works every time.
Your idea about a loc-tite product that may dissolve bearing fit is good and I'll check that out now.
I was really hoping to hear some encouraging feedback from folks who may have removed one of these sheared crank bolts...who could say it screwed out easily and cheer me up!
David

tomsheppard · Post by **tomsheppard** » 08 Jan 2003, 17:15

David, First my thanks on your treatise re cooling systems. If you can run a bead of weld around the end of the bolt, you will kill the Loctite which as you correctly surmise is applied.Arc welding is best here 'cos it is hottest. The crank being made of good metal, you will not hurt it. Then, before trying to use extractors, see if you can tap it one way or the other with a centre punch near the edge. Finally, If you have to use an extractor, a couple of tips. Wallop the end of the bolt with a flat ended drift and a lead hammer (lead hammers are best for this kind of thing; they give a dead blow.) this may shock it free. At least it will provide a surface for your centre punch prior to drilling. Drill the biggest hole you can get away with. Extractors are smaller than the bolts they are intended to extract and, being hardened are brittle and fragile. BTW there are tools to lock the flywheel which may help if your intention is a cambelt change. I am warned that it may not be a good idea to lock it with just the timing pin hole whilst removing the bolt.
Does this mean incidentally that it would be a good idea to weld a bead onto the bolt head prior to extraction when preparing to do a cam belt or head gasket job?

David W · Post by **David W** » 08 Jan 2003, 17:25

Tom,
Yes thanks for you thoughts here too.
I only wish I could get a welder near it, the broken bolt end is recessed 1/2" in the nose of the crank so it is just too risky. If the bolt ended up welded to the crank that would be a devil!
One of the most important aspects of this will be to get the first pilot hole central. The Snap-On kit I mentioned has 10 different pilot drill sleeves so you find one that is snug to the hole in the crank and that means your first drilling in the sheared bolt will be spot on.
Yes I will be heating it best I can though, and shocking the bolt end before I try the extractor, so that has as little work to do as possible.
David

Dave Burns · Post by **Dave Burns** » 09 Jan 2003, 04:41

If you are removing this bolt as part of routine maintenance i.e timing belt/water pump or what ever, then the best way to go about it is to have the engine well up to operating temperature, this softens the locking compound on the thread and also expands the bolt.
If you weren't in a position to have the engine hot, then I sympathise, I've taken a few off cold but been lucky not to have one break after the pain they can take before cracking loose.
I personaly would drill it out, staying slightly under the tapping size then pick the fragments out and retap it, if a hardened extractor breaks in the bolt then you really have got problems.
Dave

David W · Post by **David W** » 09 Jan 2003, 14:21

Thanks Dave.
Yes I usually do them hot but this car was in overnight and the engine couldn't be started for other reasons. They are so often very tight but to be honest I didn't expect it to snap...first one ever.
You make a very fair point about breaking an extractor, that's why I've bought these ones from Snap-On that are far better than the cheapish standard easy-out.
If the extractor worked first time it would make the best job, if it snaps I'll be.......err...cross. How I actually try it will be determined how it looks after I've got a good central pilot hole.
Anyway the workshop heater is on and I'll know in a couple of hours how it goes!
David

David W · Post by **David W** » 09 Jan 2003, 20:43

Dave,
Your advice on drilling out and running a tap is the route I've ended up taking after pushing the extractors to the limit of their ability and it still not budging.
Just been to buy the largest drill I dare put up it without catching the crank threads but no joy on a tap.
The engineering suppliers in our city say it is a metric bolt but seems to be a one-off diameter between M12 and M14. Have you ever found a tap for this specific bolt?
Thanks,
David

Dave Burns · Post by **Dave Burns** » 10 Jan 2003, 00:13

Hi David, the thread is ISO Metric Fine 14mm x 1.5mm the correct tapping drill is 12.5mm but if you use this it must be bang on centre or thread damage as you know will occur, I have a new crank bolt here and it is just 0.15mm (6 thou.) down on 14mm but thats to be expected because its a rolled thread, Iv'e never seen a rolled thread yet thats formed right up to the main diameter.
The thread system used on Citroens and most any european car is metric, with a mix of fine and coarse pitch threads for various applications, you certainly wont find any wierd thread size, this would be an unnecessary expense, and we all know car manufacturers don't like expense, they want it fast and cheap.
Good luck with it.
Dave

David W · Post by **David W** » 10 Jan 2003, 01:11

Dave,
That is quality info, many thanks.
I think the bolt supplies guy was having a bad day because he went out the back, tried a couple of nuts on my new crank bolt and said it was an odd in between size. As this was going into a tapping rather than a having a nut on the other end I thought that's just possible.
After putting up the previous post I measured the bolt myself and as you say it is a whisker under 14mm with as near to a 1.5 pitch as I could tell.
I'm really pleased to have your confirmation. Off to the engineering suppliers again tomorrow and I'll get then to find me a tap now we know the correct size.
About the thread damage I guess you were meaning a 12.5mm drill is the max size that will drill up inside the thread without touching it...if (yeah if!) you have the drill dead center.
David

Dave Burns · Post by **Dave Burns** » 10 Jan 2003, 01:53

David, i would use a plug tap (bottoming tap) and expose the first two threads, a tapered or second tap might start to cut a fresh thread into the originals, also a tapered tap can ride over fragments of the bolt thread without cutting it, if this happens it can lock the tap up then it breaks when it is forced out, don't forget to use cutting compound to keep the tap lubed.
If the worst comes to the worst, you can go up a size to 16mm, either fine at 1.5mm or coarse at 2mm using a 14.5 or 14mm drill respectively, allways assuming the crankshaft is not to hard to cut.
About the 12.5 drill, this is the size of the hole drilled in the crankshaft before the thread is cut, the tapping size of ISO metric threads is easily calculated by simply subtracting the pitch from the diameter.
Dave

David W · Post by **David W** » 11 Jan 2003, 18:34

For your interest...
Finally knocked/picked out the remains of the bolt after drilling it out as far as I dare.
Ran a M14x1.5 tap down the thread once and tried a new oiled bolt.
Managed to take it up to the correct torque without it feeling like stripping.
To be honest the thread in the crank nose doesn't look as good as you would wish but I will put the bolt back with Loc-tite and as long as it lasts 10 miles I don't see why it shouldn't last 50,000 to the next timing belt change point.
By that time the car will have done about 200,000mls and be 12 years old...worth about £500 or less I guess.
If I'm still looking after it then at least I'll be aware that there just could be further trouble.
Thanks for your input.
David (bit happier now!)

David W · Post by **David W** » 26 Nov 2003, 13:14

Another question on the forum has prompted me to update this.
Thankfully after over 12,000 miles this crank bolt is still holding. In the end I used a "bearing fit" type fluid and took the torque to about 80% of the book figure (it felt so tight I was so worried about that last 20% causing the crank threads to strip out.
The car has just celebrated its 10th birthday and covered almost 160K. Frankly it might as well be run until the timing belt breaks (if it gets that far) rather than risking disturbing this "bodge" to do the next routine change at 190K.
David

rg · Post by rg » 26 Nov 2003, 17:18

All,
FWIW,
A similar "bodge" on an XUD on a Pug 405 (to solve a worn keyway, in this instance) lasted at least 50K.
rg

ghostrider · Post by **ghostrider** » 29 Nov 2003, 04:32

Can anyone tell me why these bolts are done up so tight? I'm about to do my Xantia 1.9TD and last time I did my BX I had an awful job doing it wondered about using some sort of Impact socket but I cant remember the size
Pete
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