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Contaminated rear brake AGAIN!


persistant_itch

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Hey all,

So basically as the title says my rear pads are F***ked again. This is now the third time in a month. They are the same pads mind you.

Ive boiled the pads and the rotor, cleaned the crap out of them, cleaned the brake itself quite well, and they work fine for a few rides and then they start to slip again, this time it came out of nowhere and sent me off a wall onto my arse!ha

My plan was to get new pads and give the brakes a bleed maybe 3 weeks before radfest, so they'd be bedded in by the time i got there, but it looks like i'm gonna have to do that sooner.

Has anyone any idea whats causing the contamination? when i rub the rotor its got a black oily film on it, but it seems to come on quite quickly which makes me think theres a leak?could there be a seal gone somewhere?I dont want to buy new pads and have them ruined straight away you no? Just in case its relevant the brakes are hope tech trials, and the pads are hope standards (the darker ones then the pros?).

Any help is appreciated

Bernard

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Hmmm...I never had this issue before I sold you the bike.

What did you use to clean the rotor/pads apart from water?

Around the calipers there may be black dust but that is just pad material. Not too sure about a leak but re-bleeding the brakes will most likely improve their performance.

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You need new pads. Sounds like the contaminant has soaked right down into the material.

Each time you boil and clean them only the top layer is actually getting cleaned. Once you've ridden on them and worn off the layer your just exposing contaminated pad below.

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Hmmm...I never had this issue before I sold you the bike.

What did you use to clean the rotor/pads apart from water?

Around the calipers there may be black dust but that is just pad material. Not too sure about a leak but re-bleeding the brakes will most likely improve their performance.

Just used boiled water, soaked them, then a tiny bit of sandpaper to clean the surface, soaked in boiling water again and then dried and put back on. Its only the back brake, the front is working really well.

You need new pads. Sounds like the contaminant has soaked right down into the material.

Each time you boil and clean them only the top layer is actually getting cleaned. Once you've ridden on them and worn off the layer your just exposing contaminated pad below.

Yeah i was thinking id need new pads

What causes contamination, is it literally just dirt from riding?

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So basically as the title says my rear pads are F***ked again. This is now the third time in a month. They are the same pads mind you.

That's the issue unfortunately - once contaminated, always contaminated. New pads and rotor is the only 100% fix.

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Nope, nothing to do with water/mud etc. Its only really oil or lubricants which will trouble discs

It can come from a leak in the brake, or if you ever managed to mistakenly get any oil or spray onto the brake

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Could be from the piston or it could be that the bleed nipple or shroud nut aren't done up tight enough.

You'd know if it was leaking though, as there would always be some oil at the caliper and you'd be needing to re-bleed semi-regularly

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And how can I know if there is a leak? and where would it likely be?

pull your brake lever with a ziptie over night,if it leaks on the caliper pistons youll see oil/dot stuff at the back of your pads plate after that

replace pads and in the best case the rotor,too if it doesnt leak,safe way to kill every possible reason for shitty brakes

Edited by FamilyBiker
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pull your brake lever with a ziptie over night,if it leaks on the caliper pistons youll see oil/dot stuff at the back of your pads plate after that

replace pads and in the best case the rotor,too if it doesnt leak,safe way to kill every possible reason for shitty brakes

And if its leaking at the piston is it an expensive fix?

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