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Hi all, having a bit of an issue with my M785 brakes.
There is only around 1cm lever travel before the brakes are locked on, I have unscrewed the lever travel screw from both levers and this has changed nothing.
I have had this issue before with old XTs and the slightly newer XT M775 brake, no matter how much I bled them and adjusted the oil level the lever only moved 1cm before being fully on. Really like the Avid Juicy 7s I had for a few years, yes they always needed to be bled but the lever adjust actually worked.
Is there something I'm missing here?
Not sure I understand why it's a problem, however have you tried the bite point adjustment screw?
Basically, I can only pull the lever around 1cm before the brakes are locked up. Adjusting the bit point adjustment screw (what I meant by lever travel screw) makes no difference what so ever.
I'd like more level movement, so I can use the brakes modulation rather than them being off or on.
Modulation you say? With M785s? LOL
Are the pistons fully retracted with brake 'off'?
Push them in fully if not.
Sounds like they don't have much distance to cover before contacting the disc.
Too much oil when you bled them?
BP +1, shimano do some very powerful brakes, but most are on or off with little modulation....
XTs are ace...if you don't like the power get X2's they have more modulation but less power, if you ride fast, especially downhill the XTs have good modulation.
Suffolk- think you're spot on, the piston wont fully retract after braking. If I push the pistons back in I get a decent amount of lever travel, but once the lever has been squeezed a couple of times the pistons are back to the usual position.
BP and others- Cheers guys, not after masses of modulation just want some leeway between off and going over the bars, rather than a minor twitch of the finger that it is now.
Sounds like too much oil in the system. When you bled them did you use the yellow bleed block or bleed them with the pads and disc in?
Best thing to do is with the pads out and the pistons in their normal slightly out position, attach a hose to the bleed nipple, open the nipple and then push the pistons fully in. This should have the effect of pushing the excess fluid out of the caliper into the hose. Then close the bleed nipple, remove the hose from the bleed nipple and refit the pads and it should be all good. If it's not then there may be something wrong with them that needs properly looking at.
Pridds is on to something here, however if it were me I would remove the reservoir cap and then push the pistons back in. Breaking the seal or having the system open at the highest point (the brake lever) will prevent you from introducing air into the system.
After that get a bleed block and bleed them again. If you don't have a bleed kit just try the brakes after refitting the pads and reservoir cap, you may have an air free brake and it may just be a case of too much air in the system.
Pridds is on to something here,
** cough **