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Chipped SLX piston ...
 

[Closed] Chipped SLX piston - can it be repaired?

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[#8329150]

Or am I just better off buying a new brake?

I got a new pair of SLX brakes in August and the rear has been a pain in the arse. Firstly, the bloody olive didn't go in properly when I shortened the hoses, so I had to bleed them from the off. Recently the pads needed replacing, but one of the pistons would not retract fully. I put new pads in anyway, with one pretty much constantly rubbing. Then the brakes were going spongy intermittently, so I tried to bleed them again. This time it was a nightmare, I couldn't get more than a drop of fluid to go up into the lever reservoir thingy without nearly bursting a blood vessel. The whole thing went tits up and when I put everything back together, the brake just bound onto the disc with the lever flopping about.

At this point I may have lost my temper.

Deciding that it must be the sticky piston I used a ring scanner and a not inconsiderable amount of force......and broke the edge off of the piston. Now, obviously, the brake is ****ed.

Is it worth trying to fix, or should I just buy a deore for £45?

I know I shouldn't have lost my rag, but I wouldn't expect a new brake to go so wrong within six months.


 
Posted : 03/02/2017 10:59 pm
 br
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https://www.merlincycles.com/shimano-m445-disc-brakes-91238.html

£17.50, use the caliper and hose keep your SLZ lever.


 
Posted : 03/02/2017 11:02 pm
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I had a similar incident although slightly more hamfisted and knackered the piston trying to push it back in with a screwdriver....
Bought a new SLX calliper from CRC and attached it to the existing hose in minutes, then bled it a further few minutes.
Far less painful than the previous effort and restored my faith in myself as an amateur bike mechanic


 
Posted : 04/02/2017 1:49 am
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I buggered my slx caliper riding 150 miles in Wales with no pad material. New caliper from tweaks and good as new. 😆


 
Posted : 04/02/2017 2:19 am
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know I shouldn't have lost my rag, but I wouldn't expect a new brake to go so wrong within six months.

Well if you take a spanner to a ceramic piston contrary to what the instructions advise, shit happens 😕

Just buy a new caliper.


 
Posted : 04/02/2017 2:44 am
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It may not necessarily be a stuck piston, I've seen plenty of sticky master cylinders at the lever. In fact that would be where money is if you can't bleed freely. I'd got all in and buy full the new brake and never look back!


 
Posted : 04/02/2017 7:25 am
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Get a new brake and sell me the broken one cheap 🙂


 
Posted : 04/02/2017 9:21 am
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Well if you take a spanner to a ceramic piston contrary to what the instructions advise, shit happens

Wow, thanks a million for that. The brake was, in fact, already going iffy well before my slight loss of composure. You rival Jonathan Pearce for 'not understanding the linear nature of time'.

I've take br's advice. In the meantime I've stuck an old Quad Stinger I have on. The hose is a bit long, but it'll do.


 
Posted : 04/02/2017 3:03 pm
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I still reckon it's not the caliper mind... Why would it be hard to bleed if a caliper piston was stuck? Its got to be the master cylinder at the lever


 
Posted : 04/02/2017 6:51 pm