stuck cranks

[craiga]

I've broken the bottom bracket on my 97 Proflex XPX - well it has done 11 years!
Now can't get the crank off. Using the crank extractor that I've used on campag crank, it screws in tight, but then just drops out when I get pressure on it.
Might it be a different size crank with it being a Girven?
Could I use PTFE or something to make it fit tighter - I don't want to break it.

[jeffhop]

sounds to me like the threads have gone, looks like localised heat is the answer or some brute force, but i would go with the heat option and be careful of the frame.

[Colin]

On my XP-X, I just use a "standard" crank extractor that came with a Bike Tool Kit.
Seems to work OK on all of my bikes.
The threads are a bit fine, so could easily get stripped if you cross thread or use "Gorilla" strength.

Yep, try some penetrating oil and if no joy, then heat the cranks.

Col.

[craiga]

Thanks very much, I was maybe being impatient. They have not been off in 11 years.

SO WD40, Heat & Patience.

Thanks chaps

[jeffhop]

wd-40 isnt really up to that job what you need is a good penetrating oil something like this

http://www.lawson-his.co.uk/scripts/details.php?cat=Penetrating%20Oils&product=30700

let it stand overnight then try with the crank pulley and maybe it will come out, if not get a blowtorch and a really big hammer  and please be careful of the paint.

[Colin]

wd-40 isnt really up to that job what you need is a good penetrating oil something like this

http://www.lawson-his.co.uk/scripts/details.php?cat=Penetrating%20Oils&product=30700

let it stand overnight then try with the crank pulley and maybe it will come out, if not get a blowtorch and a really big hammer  and please be careful of the paint.

Correct! WD-40 is not a decent lubricant or a proper penetrating oil, it is primarily a Water Dispersant product. (reputedly developed for the US ICBM/Space program). One of their claims is that it can remove grease and indeed, I do use it as a cleaner but don't go spraying it into greased components! (I also keep it away from the Carbon parts as it is petroleum based and maybe could damage the thermoplastic....?)

Col.

[Luke]

OK back to those cranks.
You’ve stripped the dustcap thread, which is also the extractor thread.
More details please; I’ve pretty much seen all the crank/BB possibilities now.
Which side?
What’s broken or What’s left of the axle/crank etc.?
Can you get the BB out to work on it on a bench?
Can you get at least one of the cups out?

I presume you’ve got one crank off, stripping both really is bad luck.

If it’s the LHS or you can get the spider off on the RHS then your local garage is the place to go. They’ll have a steering/suspension knuckle extractor which consists of a sort of  “open spoon” that goes behind the crank, and a threaded bar that pushes on the axle where the crank extractor pushes. I bought one for my Iveco and have used it more often on my Specialised.
Just be careful though; if your axle is not contained in a vice or in the frame it will become a projectile and ping across the garage possibly causing all sorts of damage (I learnt the hard way).

On the RHS a (very very very solid) bearing puller with 2 or 3 arms could be persuaded to fit around the spider, if you have sharp enough edges between the back of the crank and the spider. If it’s rounded it’s not even worth trying.
If not I hope it’s an old style cup/ball bearing BB, in which case you take out the LHS cup enabling you to push the RH crank against the RH cup.
The RH cup is now your anvil with a hole in it, and you hit the axle with a very big hammer (via a punch) Watch out for flying axles in this case too, because when it frees it will go far.

Your worst situation is the Shimano (or equivalent) BB all attached to the RH cup, with the RH crank stuck on. If the bike’s still rideable take the crank bolt out and ride around your neighbourhood hopping all the curbs you can find...
Or stick a big crow bar between cup and crank on each side of the axle (the effort has to be symmetric) and try to lever it off.

If all that hasn’t worked it’s made a right mess of your crank and now you don’t feel so bad about taking a hacksaw to it ;-)

Do tell us how you got on.
Luke

[jeffhop]

ive just had a thought, if your replaceing the chainset and the bb angle grind it off, quicker and easier than a hacksaw and safer on the frame than either a lump hammer or a crow bar.  by the way i have a bb and chainset for sale if you need one thats been fitted to an xpx as well 

[purple gerbil]

in the past i have used the 3 legged flywheel pulley as per luke and it work's... and also take out your b/b bolt and spray with wd-40 around the axle and go for a 15 minute ride.. but go steady cos some time's it will just go.. so no standing up or the family jewel's will need kissing better

[craiga]

Success!
Many Thanks for all your help, tonight was my first chance for ages, so I thought I'd try the easiest first. Soaked with the penetrating oil & off for a ride with the misses with crank bolts off. 5 mins & off comes the chain side crank. Great, slaps it back on & bolts it up, but not too tight, rushing to get back for the football.
BUGGER - rushing - instead of one crank being at 12 and the other at 6, I'd got one at 9 & one at 6.
Would it come off? NO. Luckily I have toe clips on, but it took a crazy frog pedal motion for 20 mins before it came off again. What a relief, cramp in my thigh. The other side came off after 40 mins.
BB straight off, not tight at all, just a bit tighter than finger tight.
It's a UN51, 1.37X24 68, but no length. Measured it & it's only a 110 - even stood it next to a Campag one to make sure - definitely a 110.
What should I replace it with?
UN54  68X110  1.37X24 

[Colin]

Great, glad to hear it's sorted!

UN54  68X110  is the correct original BB size.
Mine has got a 68 x 113 on it at the mo', no real noticeable difference in Q factor, just the front derailleur needed adjusting to suit.

Mate of mine broke his chain while we were out last Thursday in the p1ss1ng rain and he conscientiously did a great repair on the chain, only to find that he hadn't threaded it through the front derailleur! <GRIN> back to square one!

Col.

[purple gerbil]

sorted!!!  glad that little trick worked.. make sure you put some copper grease on your b/b shaft/pedal arm  that help's with the creaking