/ no pressure in hydraulic breaks

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sebastien - on 26 Jun 2013
Hello,

a technical question re. hydraulic breaks Hayes Sole1: the handles almost reach the grips before actually breaking.

I have already change pads, done a bleeding, put the break pads as close as possible of the rotor. But no real change.

What did have an impact was to screw in the little screw in the break handle, which, I presume, pushes in the piston in teh fluid cable. But I had to screw in very far before it improves things. I don t thing I could go much further.

So could you tell me if/what is wrong with my breaks?

Thanks for your help!

Sébastien
Frank4short - on 26 Jun 2013
In reply to sebastien: Sounds like somewhere along the way, probably during your bleed, you got air in the lines. Go back and bleed them again and hopefully it should fix it.
sebastien - on 26 Jun 2013
In reply to Frank4short: I can try again but the problem was already there before teh bleeding.
Roadie_in_denial - on 26 Jun 2013
In reply to sebastien:

'pump' the brake lever several times in rapid succession. If the brake feels progressively firmer and with a braking point which requires less lever travel then you need to get your brakes re-bled as you have air in the system somewhere.
jkarran - on 26 Jun 2013
In reply to sebastien:

If they're 'soft' and generally ineffective but gain power progressively as you pull the handle further in, the handle gives some and increasing resistance from start of the pull to all-in against the bar then you have trapped air or a bulging pipe (probably not an issue with mountain bike brakes). Alternatively, much less likely the caliper could be flexing. Re-bleed them in line with the instructions is likely to fix them given mountain bike hoses seem to be semi-solid so are unlikely to be the problem.

If the handle pulls in most of the way with minimal resistance then goes hard allowing you to modulate brake power with lever force rather than lever position it's not the fluid/pipe/caliper, it's likely the pads are retracting too far between applications (possibly a warped or installed with run-out disk tapping them back). They then have to be pushed out each time before they contact the disk. Alternatively the screw that sets the lever-master cylinder interaction point just needs setting up properly, that's one of those personal preference set-up things you may just have to play with to get right.

All that holds true for car and motorcycle brakes, whether there are idiosyncrasies particular to mountain bike brakes I'm not aware of I don't know.
jk
sebastien - on 26 Jun 2013
Thanks a lot for the answers!
LastBoyScout on 26 Jun 2013
In reply to sebastien:

Your problem is they are spelt wrong.
benlatham07 - on 26 Jun 2013
In reply to sebastien: don't bleed them ' burp ' them first, it might just be air in the system. Have a look on you tube to find out how.
MHutch - on 27 Jun 2013
In reply to sebastien:

Hayes Sole 1 - single piston brakes, I think? Have you adjusted the the position of the pad opposite the piston? I think there's an allen key slot on the caliper?

Other possibilities - the piston is sticky, you can push it out a little way with the lever and clean it up/lubricate it to see if that improves the travel (take pads out first).

Otherwise it's probably re-bleed time, as you've missed some air somewhere. When you have the piston pushed out a bit it's worth checking to see if there is any hydraulic fluid around - ie dodgy seals.

samreddevilz - on 27 Jun 2013
In reply to sebastien: more like "a ship without sailor"
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SI - profile removed on 27 Jun 2013
In reply to sebastien: Hello, Sounds like you've got air in the lines. Having bleed my brakes a few times now I've think I've discovered the trick to getting them tight. Apply pressure on the brake lever before opening the valve, slowly open the valve until the fluid just about starts to seep through then close it again before you finish the full stroke on the lever. Much easier if you can get a friend to keep topping the reservoir up while you're pumping the fluid through.

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