[I Are Baboon]

I've got Magura Louise FR hydraulics. The rear brake seems to be rubbing just a bit on the rotor. How do I adjust the brake pads so they don't rub? I don't have the owner's manual so I haven't a clue.

This was easy with my Avid mechanicals....

 

[Dartman]

Put some card stock, like a business card, in between the rotors and pads. Give the levers a squeeze and release quickly.

Werks fer Haze.

Mike

 

[DownCycles_Stef]

The business card trick works well when first setting up brakes after a bleed. Once the pistons are extended it doesn't really work. What you need to do first is SLOWLY push the pistons back into the caliper, and I can't stress SLOWLY enough. If you push to fast or hard you may damage your reservoir or your seal/cap on your lever. Once the pistons are fully retracted, place a business card on either side of the rotor and place the pads/caliper over the rotor & cards.

Compress your lever until the pistons extend, then remove the cards and align & tighten your caliper. If your rotor only rubs in one spot as it's spinning, it's bent. You can straighten it with an adjustable wrench. Just protect the rotor from the wrench and then bend the rotor appropriately to get rid of any little whip it may have.

Finally with everything aligned and true, if there is still a slight rubbing on one side of the rotor, you may need to space out your adapter, or face off some material from your frame on your caliper mounts. If that's the case, you're better off bringing it to your LBS.

 

[I Are Baboon]

Thank you both of the advice.

Turns out my brakes were rubbing because my rotor was loose.

 

[dirtygirlmagnet]

I learned a cool trick when tuning Marta's in a hurry. If one piston is extended more than the other, without removing the wheel, grab the rotor on both sides of the caliper, and use it to push the pad back in gently. Since the pad/rotor clearance is so close, you wont have to move the rotor more than a few mm's. after a light push, squeeze the lever lightly, then push a little more, this will cause the pads to sort of even out.

 

[binary visions]

I simply do not understand in the slightest why this business card trick is supposed to work. It doesn't make any sense: the pads are self-adjusting, so as soon as the business cards are removed, they will adjust to be closer to the rotor.

Can someone please explain why they think it works? I've tried it numerous times and come up with the exact same result: as soon as I pump the brakes after I take out the business cards, the pads reset themselves to be closer to the rotor.

edit: incidentally, it came up in another thread and I questioned it, and got no response. Link.

 

[sanjuro]

I simply do not understand in the slightest why this business card trick is supposed to work. It doesn't make any sense: the pads are self-adjusting, so as soon as the business cards are removed, they will adjust to be closer to the rotor.

Can someone please explain why they think it works? I've tried it numerous times and come up with the exact same result: as soon as I pump the brakes after I take out the business cards, the pads reset themselves to be closer to the rotor.

edit: incidentally, it came up in another thread and I questioned it, and got no response. Link.

I use the business card trick to center the caliper, not to retract the pads. The assumption is that both pistons will move equally. I usually do not bother holding the brake lever either.

However, I noticed this not work all the time, and I often manually adjust the caliper. And if the pads are too close, we often let a drop of fluid out....

 

[binary visions]

I use the business card trick to center the caliper, not to retract the pads.

Well, you might do that, but everyone else thinks it spaces the pads out further.

Just out of curiosity, why do you need business cards to center the pads? What's the difference between that and just clamping the pads right up against the rotors?

 

[sanjuro]

Well, you might do that, but everyone else thinks it spaces the pads out further.

Just out of curiosity, why do you need business cards to center the pads? What's the difference between that and just clamping the pads right up against the rotors?

I tried to do it today and I still had to center the caliper manually.

 

[binary visions]

I tried to do it today and I still had to center the caliper manually.

You mean you tried to do it without the business cards? Hrm.

I always center my calipers manually, because I could never get the trick of loosening the caliper, clamping the breaks, and tightening everything down to work for me. It always rubbed. Maybe I should try it with the cards?

 

[sanjuro]

You mean you tried to do it without the business cards? Hrm.

I always center my calipers manually, because I could never get the trick of loosening the caliper, clamping the breaks, and tightening everything down to work for me. It always rubbed. Maybe I should try it with the cards?

I tried the business card trick first, then went to manual. then I tried to retracted the pistons. Finally, I got it just right.

 

[ultraNoob]

Borrowed a bike from my buddy and found out the hard way that I had no experience aligning Hydro's. Eventually retracted the pistons, loosened the caliper bolts slightly, "lightly" squeezed the levers, tightened the bolts. Worked like a charm.

If bike calipers work similar to vehicle calipers, when the pistons are pushed out due to actuation of the levers, they should also retract slightly (1-2mm) when the levers are released. Provided that you don't have any air in the system of course.

The business card trick seems to only work on mechanical calipers being that there is only one actively moving brake pad. The other pad is usually stationary and only adjustable when tools are available. With slightly loose caliper bolts, I place a business card between the rotor and the non-moving brake pad and "lightly" actuate the caliper manually. As for the active pad side, most of the adjustments are made with the cable.

 

[Boxxer]

A better business card trick:

I use the back of a white business card and hold it so I can sight down the rotor and clearly see the gap on either side. Then just adjust the caliper so its even, give the wheel a spin and call it a night.

 

[johnbryanpeters]

You mean you tried to do it without the business cards? Hrm.

I always center my calipers manually, because I could never get the trick of loosening the caliper, clamping the breaks, and tightening everything down to work for me. It always rubbed. Maybe I should try it with the cards?

For Hayes HFX, I put one card to each side of the disk, squeeze, tighten. For some reason it minimizes the tendency of the rotor to flex rather than moving the caliper body.

I used to use Maguras but dumped them because they required shims to center the calipers, a constant pain in the ass maintenance problem.

 

[GuettoBlaster]

here we go...loose up your brakes (both screws,the ones that hold the caliper in place) give the lever a squeeze and still holding the lever ,tide the screws up..this may help you center the pads,even if they're self adjusting!!!