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Hydraulic disc Brakes too tight!
#1
Hello-

I bought a set of Tektro Auriga comp hydraulic disc brakes. I got them OEM online for less than half-price. They arrived in a couple of big ziploc bags inside of a Fedex envelope.
I've finally gotten around to trying to install them-

Unfortunately, there is not enough room between the pistons to fit the pads AND the Disc! I have this problem with both the front and the back. I have tried physically pushing in the pistons, and I have removed a small amount of brake fluid (mineral oil), but the pistons just won't move in. Does anybody know how I can fix this?

Thanks!
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#2
Yes I have an idea, see those are like the automobiles front brakes. On cars we have to compress the piston with a c-clamp then install everything and put them back on. In this case you will need this tool or something similar ... http://www.amazon.com/Park-Tool-BRAKE-PISTON-PRESS/dp/B002OMNI1K/ . Then if you do not have the owners manual which should have the instructions you can go here and download it. http://www.tektro.com/04support/manual.php . If you need further advice here is park tool's procedures ... http://www.parktool.com/repair/byregion.asp?catid=14&imageField2.x=26&imageField2.y=9 .

Good luck if none of this helps come back,
Bill Smile
Good maintenance to your Bike, can make it like the wheels are, true and smooth!
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#3
Here's what's happened:

Pretty much all hydraulic brakes have a build-in feature that adjusts the position of the pistons as the pads wear down, so in theory you never need to adjust them. If you however squeeze the lever without a disc present the pads move in, and consequently the disc doesn't fit.


You don't really need a special tool to reset the pistons, just a screwdriver. Place the screwdriver between a pad and piston and push on the back of one of the pads to force the other piston back in. Repeat on the other side, you may have to push them back in stages. Don't do this with the front of the pads as you can damage the pad surface and transfer contaminants to the pads, and don't use the screwdriver directly on the piston as you'll damage them.

This requires a reasonable amount of force, but if they still won't go in it might be worth talking to the shop, as they should go back with a bit of force.
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#4
You should be able to sort this by pushing the pistons back in, see my previous post in this topic for how to do it. I should add that you will almost certainly need to take the wheel off.
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#5
(03-31-2010, 03:39 AM)JonB Wrote:  Here's what's happened:

Pretty much all hydraulic brakes have a build-in feature that adjusts the position of the pistons as the pads wear down, so in theory you never need to adjust them. If you however squeeze the lever without a disc present the pads move in, and consequently the disc doesn't fit.


You don't really need a special tool to reset the pistons, just a screwdriver. Place the screwdriver between a pad and piston and push on the back of one of the pads to force the other piston back in. Repeat on the other side, you may have to push them back in stages. Don't do this with the front of the pads as you can damage the pad surface and transfer contaminants to the pads, and don't use the screwdriver directly on the piston as you'll damage them.

This requires a reasonable amount of force, but if they still won't go in it might be worth talking to the shop, as they should go back with a bit of force.

Good tip: Rather than a screw driver though I always use the flat end of a lolly stick, then if you slip you don't scratch anything... as I did when setting up my nice new Elixers a while back..
cycling since 4 years old and never looked back!
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#6
A trick I learned with hydro's: If your brake pad is touching the disc, shove a business car on either side of the disc in between the caliper and the disc. Squeeze the brakes several times, this should give you just enough wiggle room for the disc. You can repeat the process a few times if it doesn't come out far enough.
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#7
(08-06-2010, 01:01 PM)Jordan300 Wrote:  A trick I learned with hydro's: If your brake pad is touching the disc, shove a business car on either side of the disc in between the caliper and the disc. Squeeze the brakes several times, this should give you just enough wiggle room for the disc. You can repeat the process a few times if it doesn't come out far enough.

When you suggest using a business card, you mean put one between the brake pad and the disc to give extra room, right? I just have one pad touching and am going to try this, hopefully it'll help out.
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#8
yeah while its on your bike, shove some business cards in between the disc and the pads
  Reply
#9
(08-06-2010, 01:01 PM)Jordan300 Wrote:  A trick I learned with hydro's: If your brake pad is touching the disc, shove a business car on either side of the disc in between the caliper and the disc. Squeeze the brakes several times, this should give you just enough wiggle room for the disc. You can repeat the process a few times if it doesn't come out far enough.

This worked for me -- had to jam two cards in pretty good, but success. Thanks!!!
  Reply
#10
Pretty awesome. It's amazing how valuable these little tricks can become.
  Reply
#11
love the card trick, that's great thanks!
  Reply


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