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I have a bike with SRAM Apex hydraulic disc brakes. They do not have contact point adjustment, but I want the lever to firm up earlier in its travel. Can I just overfill my brakes with fluid to adjust contact point?

If so, what would be the best way to do it? I do not want to overdo it and be unable to fit the pads and rotor back in.

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No - that would lightly pressurise the system all the time.

From https://www.sram.com/avid/setup-guides/hydraulic-brake-setup

Note: The Contact-Point Adjustment DOES NOT move the pads.

Instead you want to try the reach adjust, and try tweaking the caliper mounting bolts so the caliper is aligned how you want it.

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  • Remember , NEVER squeeze the brake lever without a rotor between the pads,
    – Criggie
    Sep 15 '16 at 5:34
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No and yes. You could do this, but the brake basically doesn't have any room to give before rub is going to be an issue. If you're having problems with the lever bottoming and using the reach adjust doesn't help, you might try just bleeding the brake(s) if you haven't done so already, in case that helps. If it's easy to bottom out the lever, there's some kind of problem. If the lever isn't bottoming and you just don't like the amount of travel necessary to reach full power, yeah, that's kind of how these are.

If you really want to intentionally overfill a brake, I believe that bleeding it with the pistons extended more than usual would do it. I.e., sand some material off the plastic caliper block so it allows more protrusion. You could also try very carefully just pulling the lever with the wheel out and intentionally over-extending the pistons. This is definitely an at-your-own-risk plan though.

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  • This will work, but only until the pads wear and the contact point moves back to where it's designed to be.
    – alex
    Sep 15 '16 at 9:33
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No, overfilling the tank/hose will probably or not work because there is already enough fluid, or it will just cause the pistons to be further out and to make the pads rub against the rotor.

The best way is to adjust the levers from the adjustment screw next to them (normally a 2 or 3 mm Allen key hole fitting/screw, have a look if you have it. If you don't have it it means that your levers have been designed and produced only to have one position, and they believe is the best.

Never press the brakes when there is no wheel on because the pistons will start to come out, and eventually they'll be pushed out and also the oil; this way you'll loose the oil, have to quickly clean the caliper, and probably the pads will be now contaminated, and you'll have to change them.

The pads in fact soak in oil and stop to work/don't brake anymore, and the oil is highly corrosive.

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