I was reinstalling an ultegra triple crankset today after swapping the 39 tooth chainring for a 44 tooth chainring, I grabbed hold of the pedal to ratate the cranks whilst checking the front mech adjustment and it just came off in my hand.
After wiping off
I wasn't aware of anything untowards about the pedal the last time I rode that particular crankset. To my inexperienced eye it looks like it has unscrewed itself at the far end of the spindle.
Is this pedal salvageable? All the ball bearings etc are still in the spindle housing
I just don't see how it came off. Something has to come undone or stripped.
I agree. I stood there in shock for a good minute. I'll have a closer look at the weekend but they've had a couple of hard years and I have a pair of A520 in reserve.
Probably just come undone and may be a straight re assembly if the securing nut is still in the SPD (presumably) As you say its odd that you didn't have any notice of anything untowards but I'd be happy it was when at home rather than in action.
Option 2 is you just don't know your own strength best not shake anyones hand until you know which
I'd go for rebuild then fit spare set if bits are missing.
check that the end of the spindle has not been sheared off; it isn't unknown.
If the cone and locknut have come unscrewed then you may be able to repair the pedal without undue expense, but getting the outer bearing sleeve out of the pedal body will be kind of tricky; it is a push fit into the pedal body and there isn't a very simple way of making a puller to remove it once you get to the point you are at.
You can buy a new axle assy to replace a broken one, but I would suggest that you don't bother doing that until you have removed the old parts from the pedal body.
If the parts have simply come unscrewed, this is arguably symptomatic of a common issue with SPDs, to whit that the RH pedal bearing slackens and the LH pedal bearing precesses itself tighter. Some SPDs go on for years with no worries but most move a bit and some move a lot. I always service mine after a few hundred miles and I make sure the locknuts are properly tight.
A quick look tonight suggests that the best use of time and money is a replacement pair of M540. As Brucey said, I could'nt get the first sleeve to move let alone the one further in.
I had a similar incident recently with my cannondale coda RH SPD pedal. I went to unclip and the whole pedal came off the spindle still attached to my shoe. Fortunately these are sealed bearings so no balls to lose. The plastic locknut at the crank end of the bearing must have come loose allowing it to unscrew over time. I thought precession should have prevented this! Fortunately I was able to refit the pedal, tighten the plastic retaining nut by hand and complete the ride allowing me to sort it at home later.
Last edited by rjb on 7 Nov 2014, 4:05pm, edited 1 time in total.
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway X2, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840
update; 'Freeflow' had kindly let me examine the failed pedals and this is what I found;
Amazingly Freeflow had (somehow!) managed to start the broken axle into the cone again, even though it could have been sitting at any angle inside the pedal body.
The fracture in the spindle had occurred between the cone and the locknut.
A quick look under the microscope shows that the fracture is almost entirely brittle in nature with no real signs of obvious beach marks (fatigue) or anything. I am suspicious that the root cause is hydrogen cracking in the steel; this is likely to occur in certain (very hard) steels if they are not heat treated correctly and/or are chrome plated using the wrong parameters, and then see high static stress levels.
I managed to retrieve the locknut and the end of spindle from the pedal too, and I didn't have to manufacture a special puller either ( that the spindle was started into the cone was enough for that). The locknut is tight on the spindle end; they are usually held on with threadlock.
One possible cause of high stress may have been how tight the locknut was; I'll check the other one to see, but it may not tell me that much; in service the LH cone tightens (so loosens on the locknuts) and the RH cone backs off (so tightens against the locknut).
I don't think that high stress from the locknut can be the sole cause of failure, because these parts are in this region identical in design to M520 and M540 pedals, which don't break in the same way (that I know of). However it may be a contributing factor; IIRC these pedals seem to break on the RH side more than the LH side, and the RH side is where there may be a greater force between the locknut and the cone.
If anyone has the same failure then I suggest that all the balls are removed from the pedal, and then an attempt is made to start the spindle end back into the cone. [By peering inside the pedal with a torch, cleaning etc you should be able to see that the cone has nothing threaded up the middle of it, and that it is possible to do at all.] Once rethreaded, the pedal can then be disassembled in the usual way, although I had to use a little brute force to get the last few mm of the sleeve to come free, presumably because the ball bearings were not quite in the usual places.
Obviously if the spindle is broken so that the cone and locknut have come away in one lump you can't get a pull on the bearing sleeve in the same way. In this case a puller will be needed; the puller must go up a 9.5mm bore, and have a shallow end to it (there isn't much room in there if the cone and locknut are rattling around inside). I reckon it probably has to be an expanding puller of some kind in which case the expanding end should be no more than 1.5mm deep and no more than 10.9mm dia when expanded.
best not shake anyones hand until you know which 
