Hydraulic brake problem
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Hydraulic brake problem
My wife’s tourer has Shimano Hydraulic brakes which work well most of the time. However, if comes down a steep hill with them on a lot (she’s not brave), they bind for a while once at the bottom. They can be pushed back and even seem to unbind themselves slowly. Any ideas?
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Re: Hydraulic brake problem
It sounds like they’re being allowed to over heat by not being modulated effectively enough. If they’re being pushed, by steep descents / fast riding, I’d hazard a guess that the modulation technique needs to be refined a bit.
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Re: Hydraulic brake problem
Mmm. I’ve never had that problem myself, even while using brakes heavily.
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Re: Hydraulic brake problem
Should probably that these are normal descents, not very fast and no load. Only seems to be a recent thing too.
Re: Hydraulic brake problem
Sounds like heating and cooling of the mineral oil to me. Depends on what type of system you have, what you can try. But if this is a new problem, then a bleed to get any air out would help.
Re: Hydraulic brake problem
What model of brake?
If they are a closed system, the hydraulic fluid can expand with the heat from the brake, pushing the brake on.
It can also happen with open systems if you don't fully release the brake lever to open the reservoir port.
The continuous braking of a timid rider on a steep hill is just about the worst thing you can do for generating heat.
Intermittent plummet and stop braking gives fewer problems - not only do the brakes get a chance to cool during the plummet phase, air resistance does a lot of the braking for you, so there's less total heat going in to the brakes.
One thing that can help with a timid rider is alternating use of the front and rear brakes, which gives the cooling periods, if not the air braking.
Air in the system, or water in the brake fluid, can cause loss of braking.
If they are a closed system, the hydraulic fluid can expand with the heat from the brake, pushing the brake on.
It can also happen with open systems if you don't fully release the brake lever to open the reservoir port.
The continuous braking of a timid rider on a steep hill is just about the worst thing you can do for generating heat.
Intermittent plummet and stop braking gives fewer problems - not only do the brakes get a chance to cool during the plummet phase, air resistance does a lot of the braking for you, so there's less total heat going in to the brakes.
One thing that can help with a timid rider is alternating use of the front and rear brakes, which gives the cooling periods, if not the air braking.
Air in the system, or water in the brake fluid, can cause loss of braking.
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Re: Hydraulic brake problem
The brakes are Shimano MT200.
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Re: Hydraulic brake problem
Thanks for replies.
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Re: Hydraulic brake problem
Update.
Had the brakes bled and rotors cleaned. Problem is still there. I decided to try the bike myself and got the problem too. Not a lot of braking. 25m of dragging the brakes followed by pulling to a stop made the brakes rub enough that the wheel was reluctant to turn. I’ve been using hydraulic brakes for years and never had this problem. Anything else I could try.
Had the brakes bled and rotors cleaned. Problem is still there. I decided to try the bike myself and got the problem too. Not a lot of braking. 25m of dragging the brakes followed by pulling to a stop made the brakes rub enough that the wheel was reluctant to turn. I’ve been using hydraulic brakes for years and never had this problem. Anything else I could try.
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Re: Hydraulic brake problem
Is the caliper centred on the rotor? If not then the braking can be poor and generate a bit of extra heat from nearest pad rubbing first before furthest pad starts clamping.
Re: Hydraulic brake problem
If you haven't already, try cleaning the seals as it could be sticking pistons
https://www.youtube.com/watch?v=vQXFFgRButo
https://www.youtube.com/watch?v=vQXFFgRButo
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Re: Hydraulic brake problem
I realigned them too.wirral_cyclist wrote: ↑29 May 2021, 1:08pm Is the caliper centred on the rotor? If not then the braking can be poor and generate a bit of extra heat from nearest pad rubbing first before furthest pad starts clamping.
Re: Hydraulic brake problem
Great video. I don't have any bikes with hydraulic brakes, but if I ever do, now I know.PH wrote: ↑29 May 2021, 1:33pm If you haven't already, try cleaning the seals as it could be sticking pistons
https://www.youtube.com/watch?v=vQXFFgRButo
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Re: Hydraulic brake problem
I’ll give the seal clean a go.