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One of my Shimano SP-M520 pedals has gotten quite stiff on the spindle (i.e. the pedal doesn't spin easily anymore). Servicing the bearings requires first removing this nylon nut:

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And the correct way to do that is with a Shimano TL-PD40 wrench adapter:

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However, I'm in an area where it's hard to get bike maintenance parts and I don't own a TL-PD40. So I'm wondering is there any other way to get this nylon nut off that won't just shred it to pieces? I thought I read somewhere that you can use vice-grips (locking plyers/ mole-grips). Are there any other better options I should consider?

Thanks.

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  • Even some mechanic advice videos on YT state "use a mole grip if all else fails". If you are concerned about trashing the nut in the process, what if you cover it in tape and then use the mole grip? That's no pro advice.
    – DoNuT
    Aug 28, 2023 at 11:21
  • Do you have access to a grinder and an old socket of suitable size?
    – Criggie
    Aug 28, 2023 at 12:37
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    @Criggie No access to a grinder unfortunately. I did notice the reverse threading - that's actually marked on the nylon collar on the pedal as well. I might have a line on the proper tool from through a local WhatsApp MTB group. TBD.
    – SSilk
    Aug 28, 2023 at 13:29
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    @Criggie it's the opposite thread to the pedal attachment thread, so left hand on the right and right on the left. I've just serviced mine for the first time. I used mole grips (self locking pliers). They caused cosmetic damage but those pedals look pretty knackered anyway. And so long as I tightened everything properly I shouldn't need to open them very often. I've probably used them for 30 000km and they weren't new when I got them
    – Chris H
    Aug 30, 2023 at 5:41
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    BTW mine were surprisingly clean inside given the conditions I ride in, but it wouldn't surprise me if stiffness meant dirt in there. If you need to strip it right down, be sure to keep track of all the tiny balls. Also note that you can grease them (at both ends) by just loosening the cone a lot, but that can let the balls out and make sure the other end seats nicely back together - it doesn't really want to.
    – Chris H
    Aug 30, 2023 at 5:46

2 Answers 2

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It is possible to remove it using vice grips or slip joint pliers, but I wouldn’t recommend planning to do that over and over. The plastic will get chewed up very quickly. As a last resort, sure, but if your pedals are just a little stiff, I’d recommend holding off on that approach and trying to source a workable tool.

If you have access to a 3D printer or printing service, you could try fabricating a suitable tool. Alternatively, there are lots of TL-PD40 knockoffs available on the internet. I’m currently using a beautifully machined aluminum socket version that I got for like $4 shipped.

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I've had good luck using a 19 or 20mm, 12 point socket to loosen the lock bushing (the plastic part in question)on Shimano pedals. The TL-PD40 is quite inexpensive (it, too, is plastic)--just a couple USD--so when you're able it's a pretty cheap investment. Locking pliers will work as well, but as others have mentioned, continued use of those will deform the bushing in short order.

It's helpful to insert the appropriate sized Allen wrench (6 or 8mm, depending) in the end of the pedal then secure the wrench in a vise. This will hold the pedal secure and also allow you to work on the bushing with both hands. On Shimano pedals, the lock bushing is left hand threaded on the right pedal. To loosen the lock bushing on the right pedal you would turn the bushing clockwise. Conversely, the left pedal lock bushing is conventional right hand threaded, so loosening it requires counter-clockwise rotation of the bushing. There's at least 30mm of fine threads on a lock bushing so it takes a lot of turns to free the axle assembly from the pedal body.

Once the axle assembly is free, you can clean it up to better view the bearings and their situation. At the end of the assembly are the 10mm cone nut and 7mm lock nut. You'll need to secure the cone nut while you loosen the lock nut. With the lock nut loose you can then turn the cone nut to set the bearing preload. You state your pedal is too tight, so loosening the cone nut would be the action necessary (if there are no problems with the bearing balls--missing or deformed typically). It's likely that the cone nut will need a 1/2 turn or less to get a better adjustment on the preload. There's a very fine window between too loose and too tight. Again, the threading for the cone nut/lock nut is RIGHT pedal--left hand thread & LEFT pedal--right hand thread.

Cleaned and greased the pedal should run smooth again.

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  • Regarding cone nut threading direction: bicycles.stackexchange.com/questions/72067/…
    – MaplePanda
    Sep 4, 2023 at 18:40
  • I answered the question you posed in that link. A look-up of the M540 pedal on the Shimano tech doc site would only give me the Exploded View and a Shop Instructions. Neither was helpful in regard to threading. The shop instructions simply refer you to a mechanic or dealer should you have problems with the rotating mechanism. In the EV, there are separate part numbers for the left and right lock bushing, but that's not definitive. In my answer here, I made an assumption based on my flat pedal experience and the info in the Dealer Manual for PD-M8140 et al.
    – Jeff
    Sep 6, 2023 at 1:03

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