A few weeks back, when trying to refit the v-brakes on my son's MTB after taking the wheel off, I shattered a threaded plastic washer on his Shimano brake & gear lever (ST EF500).

I call it a threaded washer, but I'm not sure of the part name. It is the black plastic item I've ringed in red in the picture of the non-damage brake lever:

Close up of brake lever with the part in question there

I can't identify the part to get a replacement. I know I can get a pair of replacement levers for about £25, but I'd rather not spend that when I just want the plastic washer thing. I've searched for 'Shimano plastic washer', but that returns part for fishing rods!

Can anyone tell me the name of the part, please?

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    You could also remove the cable (just align the slit in the bolt with the slit in the lever housing), remove the bolt, and take it to your local bike (work)shop. There's a chance they've got an old brake lever lying around with a matching lock ring they'll give for (almost) free. Apr 2 at 7:28
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    BTW most aren't plastic, which won't have helped your search, but also "washer" is rarely used to refer to threaded parts, even if very thin
    – Chris H
    Apr 2 at 8:03

2 Answers 2


I'd call it a lock ring.

It is possible to buy a "barrel adjuster" like this, which will replace the hollow bolt and the lock ring.

Do be aware there are at least two thread sizes where the adjuster threads into the brake lever. Yours looks like the larger 10mm of the two - the other size is M6 or 6mm and is noticeably skinnier, and won't interchange.

enter image description here

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    @GrandMasterFlush yep in this photo its just coloured silver, but has the same purpose, to prevent movement of the barrel adjuster (ie, the hollow bolt with a slot down the side) I don't think you'll find the washer by itself, though a home-garage machinist might be able to make one.
    – Criggie
    Apr 1 at 9:41
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    Thank you! That's made it a lot easier now I know what I'm searching for - and hopefully cheaper! Apr 1 at 9:44
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    It could also be called a "barrel adjuster lock nut" - but a whole barrel adjuster is probably easier to find. I have the same lever (or near enough) so might be able to confirm the thread later
    – Chris H
    Apr 1 at 11:39
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    Checked, definitely the big size (M10 - it measures just under 10mm as expected from the form of the thread)
    – Chris H
    Apr 1 at 18:48
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Just as a complement to Criggie's already valid answer, Shimano calls the "barrel adjuster" a brake cable adjusting bolt and nut. So specifically for the part you are asking for, that would be the nut of the brake cable adjusting bolt.

For your particular model of lever, the ST-EF500, the part number is Y8UM98010 which includes the bolt and the nut. The thread size is M10 and the bolt is 16 mm.

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    Excellent, thank you, that's very helpful. At £2.99, a lot cheaper than a whole lever system. Apr 2 at 16:47

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