Shimano Brakes - Piston Guides Cracked Plastic - ServoWave

M8000 lever? If so I’ll have a look.

Can’t say I’ve heard of that happening before. Internet/forums tend to give an exaggerated impression of issues.

never heard of it either, but then some people 3d print an entire master cylinder dust shield cover for another problem that much of pinkbike suggests doesn't exist.

goddamit, my kids slx brake on his dirtjumper have exactly this.
He took a huge crash on it though when it was freshly built.

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Happened to my five year old M7000 lever about this time last year after the bike toppled over sideways - carried on using it until August this year....still usable but annoyingly clicky at times. Intend taking it apart over the winter for a look. Was thinking a big wodge of Sugru might be enough.

Tried Superglue already, however getting the cracked part in with the free stroke adjustment just caused it to crack again. After supergluing it again, I removed the free stroke adjustment and put it back in - lasted a few rides before it cracked open again.

Depending on where yours has cracked (looks to be a similar place to mine) and you may have better luck.

It only about a 2min task to remove the lever and link to allow access to the 2 plastic guide tracks (there is one on the top and bottom)

@sillyoldman- Yes M8000 right hand lever - Although looks to be the same part as used in a few Shimano Brakes - Deore and below don't have the hooks for the free stroke adjustment which is about the only difference I think.

Still used today on the 7100/8100/9100 series.

I've got a set hung on the wall with the same issue. They were on my lads bike, small lie down and it broke in the same place.

Pretty sure I'll have some of these in the box full of dead shimano levers. I've never broken one of thos platic guides, they always fail at the pistons/seals for me. 

Happy to post em out if anyone wants one. Drop me a message, should have some from M8000 and some cheaper deore levers too.

You can replace the piston seals with aftermarket jobs off eBay.

Oh, I've got one that's gone clicky, doesn't stop it working and not that noticeable when riding so I'd not looked into it yet. 

Maybe that's what's causing it 

@sillyoldman yeah, I realised that fairly recently. I've moved to M4100 levers now. More reliable, really good modulation,  no wandering bite point, loads of power, cheap to buy and they fit my shovel hands really well and they put the gear shifter in a usable spot with Ispec ev mounts too. A bit big and clunky looking, but then, so am I! They seem to last ages, haven't had to replace any yet.

I could probably get the seals, fix the levers and sell them on but hardly seems worth it.

@peanutcracknell 👍

Also messaged you, ta.

Hi @StuF - If when the lever is pulled and it doesn't move smoothly throughout the pull - then Yes it is likely that one (or both) of the plastic guides has broken. The clicking you are likely hearing is the push rod lever pivot guides moving out of the guide track slightly (due to the breakage).

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Turns out both my plastic guides had cracked; one side held in situ, lost half the other. Very grateful to peanutcracknell for coming through. Worth noting CRC's mental sale prices have 4100 levers (with 401 caliper and hose!) for less than £20 atm.

Looks at Hope brake lever...

Smiles 🙂

Looks at empty wallet and bank balance ….😜

hehe

The Tech 4 look awesome, just out of my budget

The Tech 4 look awesome, just out of my budget

I got a bikes worth of tech4 V4's for 320 in the CRC sale.

You can get a bikes worth of T4E4 for £300 One brake from CRC(black) then price match from Tredz. Viola pair of T4 E4's for 100 quid less that standard retail

Big thanks to @peanutcracknell for taking the time and effort to ship out some spare plastic guides.

unfortunately they are different and don’t fit in my M8000 level (right hand).

if someone else can make use of them I can pass them on to you, picture below for reference (M8000 is on the bottom)

M8000 guides on the bottom (Not sure which model the top ones are I'm afraid)

That's annoying that they didn't fit. The ones I sent you were out of an M785 lever (right hand)

Good luck with the search for the right parts, but I wouldn't have thought it should be too hard, must a few others with failed seals lying around somewhere. 

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Cheers, mate! I might beef these up with Sugru when I rebuild the lever.

Easy job, working lever again. I kind of understand why Shimano don't make some spares available for safety critical items like brakes, to prevent halfwits tinkering, spannering themselves then taking legal action. It does seem a pity, though, that cheap and easily replaced components like these piston guides aren't available. If this breaking problem is widespread (I hadn't been aware of it) I'm surprised nobody has monetised it by knocking out replacements - anodised CNC piston guide, anyone?

Great stuff, glad to hear you've got it back together and working.

Glad you managed to get your back up and running 👍 big thanks to community members like @peanutcracknell for helping out.

I’m still after some right hand guides if anyone reads down this far ,,, hehe

Even if Shimano didn’t sell to the public at least allow your LBS to have some and they could get a few ££ for the repairs, win/win

I have seen people selling 3D printed ones, but with this being some random at home,  I don’t think I trust my front teeth to try though.

As to why no CNC milled parts (like the replacement pistons) I think you answered that yourself  (I hadn’t been aware of it)  😜