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Brakes..too much fl...
 

[Closed] Brakes..too much fluid?

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[#11083338]

Just building a bitsa bike.

Shimano deore brake which doesn't rub on the disc and  pistons that retract but has no throw whatsoever.

Feels as if there is too much fluid in there. Have squirted a bit out but still feels the same.

Any ideas?


 
Posted : 10/03/2020 2:48 pm
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Letting fluid out of the reservoir won't make any difference to lever throw.

Edit. And letting fluid out the bottom is the same as letting fluid out the reservoir. The reservoir is at the top and will keep filling the system until the reservoir is empty.


 
Posted : 10/03/2020 3:20 pm
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I'd remove the reservoir cap and make sure the pistons are fully retracted, levering them back if required (leave the pads in and use something soft). Some pads are thicker than the OEM Shimano ones so that's something else to consider.

I used to over-fill my old XTRs as I like minimal lever throw. I'd do this by pumping the pistons out a little and then topping the system up.


 
Posted : 10/03/2020 3:29 pm
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I used to over-fill my old XTRs as I like minimal lever throw. I’d do this by pumping the pistons out a little and then topping the system up.

That should only last until the pads are incrementally worn though. It won't affect how much the caliper seals can move which is what sets the lever throw.


 
Posted : 10/03/2020 6:01 pm
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Aye, but when they are over-filled, the seals can't move the piston back so far.


 
Posted : 11/03/2020 1:39 am
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when they are over-filled, the seals can’t move the piston back so far.

Shimano deore brake which doesn’t rub on the disc and pistons that retract but has no throw whatsoever.

If the pistons are retracting and the pads aren't rubbing, then letting fluid out won't make any difference. You should be able to adjust the lever position, but hydro disk brakes aren't supposed to have much throw before engagement.


 
Posted : 11/03/2020 3:12 am
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The pistons were moving but not as much as they should.

Smeared brake fluid on them ,worked them a few times ,cleaned up and all seems well.


 
Posted : 11/03/2020 8:40 am