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I have an old Magura Julie disk brake. It seams that new pads are too thick for the brake. I already tried 2 different types. But when I insert the new pads the gap between the pads is completely closed. There's no gap left for the disk.

Re-inserting the old pads is no problem.

Are there brake pads with different thicknesses?

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  • After all I ended up replacing the break. I got a brand new one for 60 CHF. That's just twice the price of new pads. Not XTR of course. But good enough to replace the ~10 years old julie.
    – BetaRide
    Aug 17, 2015 at 20:38

6 Answers 6

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Did you push the pistons back into the callipers?

Hydraulic brakes automatically adjust for pad wear and the home position of the pistons moves slightly out. When you change pads you need to gently push the pistons back in gently with something like a plastic tire lever to return the fluid to the reservoir, then pump the lever to set the correct level of adjustment for the new pads.

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  • Yes I did. I even dismanteled the whole brake shoe, emptied the whole fluid and put it together and refilled the system. But there's no change. The pads still do not fit.
    – BetaRide
    Aug 17, 2015 at 14:26
  • Can you add some pictures to your question?
    – alex
    Aug 17, 2015 at 14:45
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I solved this by inserting the new brake pads even though they were pressed together tightly, then twisting a flathead screwdriver between the metal outer edges of the pads, forcing them apart a bit. Then I used the small gap between the pads to wedge a big flathead screwdriver between them (carefully), which completely pushed them apart and reset the calipers. This was the only way I could get enough leverage to reset the calipers with limited tools, even though the screwdriver does slightly damage the resin on the pad. Wasn't an issue for me.

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  • I had the same problem with my former pads. They were close to impossible to get in and they took some beating before I was finished. The ones I changes last weekend were much easier. They are of different brands (i cannot remember which) Next time they are so very hard I intend to file a sharper edge on the disc in one of the places it is wider. Not Sharp but so sharp I can get it between the pads.
    – LosManos
    Aug 27, 2018 at 19:41
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    Welcome to the site. If you're spreading pads using a tool like this, you could always pop the old pads back in to lever against. If you're throwing them away it's less of a trouble if they get damaged instead.
    – Swifty
    Aug 27, 2018 at 20:42
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Are there brake pads with different thicknesses?

No. You need to reset your pistons before installing the new pads.

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  • The problem is indeed that it's no longer possible to fully reset the pistons. Even dismantling everything, cleaning and refilling the brake system didn't solve the problem. It seams that something prevented the pistons from completely resetting. After investing several hours I decided to give up and spend 60 CHF for new brakes.
    – BetaRide
    Aug 18, 2015 at 6:02
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Use one of the old worn pads as a spacer between the new ones. Push them in between the caliper and pull the brake lever a few times they will adjust and you can drop the assembly back on.

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When you replace the pads, the pistons are self adjusted to the thin worn pads. The new thicker pads will not fit before you push the pistons back.

I use flat scewdriver to push the pads back before removing them (slightly rotating). This damages the pads but who cares about the worn already pads we will trash immediately after removal?

There is also a special "piston pusher" tool for this.

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  • Another popular choice is a plastic tyre lever.
    – Criggie
    Apr 8, 2023 at 21:13
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One possibility where this can happen is if someone has bled the brakes without inserting a bleeding block between the pistons. With new pads and disk between the pistons, in theory you could bleed the system without the bleeding block. However, if you bleed the system with old pads and disk between the pistons, the system becomes overfilled with brake fluid, and you are never able to install a new set of pads anymore, unless you untighten the bleed port screw on the levers, and push the pistons in with the bleed port screw removed.

Warning: pushing the pistons in with the bleed port screw removed will be messy, brake fluid will leak out from the levers.

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