LoFarkas,

Shimano lists the 540s as sealed cartridge bearings, and I'm under the impression that they are not servicable.. other than putting in new cartridges. Though, I haven't been able to find a service guide online.

The Wellgo pedal in the picture started experiencing outer bearing failure while i was grinding up a hill on my commute.. Within 2km, the remains of the bearing ate the nut at the end of the axle, allowing it to slide out. I was able to ride it home by keeping inward pressure on the pedal body.

When my first set of M540s started making snapping sounds in a similar manner, I was sure to get them back to the bike shop right away..

Now that my second set is doing it, I'm starting to have doubts about the quality of the product.
I'm going to have to go back to the shop and see if they can do anything about these pedals.