Originally Posted by
davidad
Yours probably need to be taken apart and cleaned. The axle acts as the cone and is likely pitted. If so it's best to replace the pedals.
I run shimano SPD pedals and evey 2500 to 5000 miles pull the cartridge out and clean the housing. I then fill it with grease and install the cartridge pushing out the old grease in the cartridge.
I did this with my original Shimano XT-grade PD-M737 pedals. They lasted 15 years before the clip mechanism broke apart. The bearings were still good.
In the OP's case, it's probably not worth it to overhaul the pedals. Replace 'em.