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  1. #1
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    Do I really need to remove the lefty to replace my brakes?

    I just received a new set of XT hydraulic disc brakes to replace the brakes that came with my RZ 120. They are pre-bled and fully assembled. I'd like to avoid messing with the hoses, bleeding, etc. It appears that you can't fit either the caliper or brake lever through the space between the Lefty and the headtube.Do I really have to remove the Lefty to be able to remove the old brakes and install the new ones???

  2. #2
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    Probably have to, but the simplest way is to get a buddy to help you and remove the hose near the lever, be quick and with 2 pairs off hands you won't get much air in it or make a mess of things. If you do, don't start pumping the lever until the bike has sat, sometimes with shimano's you can wait and any air that enters the system can work its way to the resevoir when you pull the resevoir cap and lightly work the lever back and forth.

  3. #3
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    Thanks for the tip. I think that I'll give that a try. After looking at the lefty manual, I'd rather not get involved with taking it off if I don't have to.

  4. #4
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    Quote Originally Posted by rider70
    Thanks for the tip. I think that I'll give that a try. After looking at the lefty manual, I'd rather not get involved with taking it off if I don't have to.
    Have you looked into how much work it might take you to re bleed the brakes if you end up having a accident while doing that? I would review and see which one would be more difficult for you to perform, bleeding the brakes or removing the lefty. Of course if done correctly you wouldnt have to bleed the brakes at all, however if you mess up..you may be in a situation a lot worse then just dealing with a few bearings.

  5. #5
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    Just swapped out mechanicals to hydro's on mine, and went "moto" style, so no need to remove the lefty.

  6. #6
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    Removing the steerer tube is a pretty straightforward job. Way less work than re-bleeding hydros.

  7. #7
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    So I got the brakes installed, but I have not properly run the hoses between the Lefty and the head tube. I realized that I will need to trim the hose for the rear brake and I decided to wait until I was ready to do that so that I could limit the number of times I disconnected the hose from the brake lever.

    Shimano has a really cool bulletin that describes how to trim a hose without having to bleed the brake. They recommend removing the pads and extracting the pistons before disconnecting the hose from the brake lever. This way you can push any air back out of the hose when you push the pistons back into place when you are finished. I suppose that this will work equally well whether you are trimming the hose or just disconnecting it to thread it past the Lefty.

    I won't have time to mess around with trimming the hose until next week. I'll try the process described in the Shimano bulletin and let everyone know how it goes.

    But, the new XT brakes are functional and feel great. They are exactly the performance that I expected when I was getting my first hydraulic brakes on my new bike. Too bad that I had to spend the $$$ on the upgrade to get it.

    Thanks for everyone's input!
    Last edited by rider70; 07-22-2010 at 09:48 PM.

  8. #8
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    I run both of my Lefty equipped bikes with the hoses outside the headtube and upper. It's a personal preference and doesn't affect performance.
    2014 Cannondale F29 Carbon 3
    2009 GT Peace 9R SS
    2008 Cannondale Prophet 4, Lefty Max TPC

  9. #9
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    The way that I have done it for my bikes is to only slide the steerer (the Si Integrated) up past the bottom clamp. This should allow you to gently pull the bottom of the lefty out and slide either the lever or the caliper through. I just did it with a pair of XT's.

  10. #10
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    Years ago when I replaced the rear rim brake with a Maggie hydraulic disc (The Louise). I removed the Lefty because I didn't want got through the bleed process. And I had bought a bleed kit with it. It wasn't difficult and the Lefty really didn't have to be removed. I only had to remove the uppper "link arm".

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