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Shimano hose shortening

.blitz.blitz Posts: 6,588
edited March 2014 in MTB workshop & tech
Afternoon all. So I've read how to do it and I have the olives/yellow block thing & tools.

Is it really possible to cut the hose, insert a new olive and re-attach the hose to the caliper without introducing air into the system?

Am a bit paranoid about limp brakes any advice is most welcome.

Posts

  • rhextrhext Posts: 1,639
    Don't know the answer to your question, but why not just try it? It's not a particularly big deal to bleed the brakes afterwards.
  • supersonicsupersonic Posts: 82,708 Lives Here
    Is usually fine if you follow the instuctions. A above, a bleed afterwards is easy anyway. Make sure you use good cutters.
  • gilesjukgilesjuk Posts: 340
    I'd recommend to replace the hoses and fittings with Goodridge stuff.

    Why? firstly the hoses are better, less flex when braking. Secondly the fittings are reusable. You undo them with a spanner and you can shorten the hose then reuse the connector.

    You still need to bleed the brakes of course.
  • jairajjairaj Posts: 3,009
    This is my thinking:

    If you remove the hose at the lever end, shorten then re-attach.
    There is less chance of air getting into the calliper and should be easier to bleed as any air should float up to the lever and out of the reservoir.

    Does that make any sense and is my thinking correct?
  • 101_North101_North Posts: 607
    I shortened the hose on my new XT's but bled them afterwards. I reckon it would be easy enough to do without bleeding though.

    When I removed the levers I lost no fluid from them so the key would be keeping the hose perfectly upright for cutting and inserting the new olive. The new olive was very tight and needed to be tapped in with a rubber mallet so you need to have the yellow blocks as close to the cutting point as possible to minimise movement.

    The bleeding process was so easy though I'd recommend just bleeding them. Caliper up seemed to work best and took about 5 mins per end.

    101
  • nicklousenicklouse Posts: 81,520 Lives Here
    .blitz wrote:
    Afternoon all. So I've read how to do it and I have the olives/yellow block thing & tools.

    Is it really possible to cut the hose, insert a new olive and re-attach the hose to the caliper without introducing air into the system?

    Am a bit paranoid about limp brakes any advice is most welcome.

    some times it works fine some times not. as Sonic says a bleed is not hard.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
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  • mister pmister p Posts: 405
    I have done quite a few brakes without needing to rebleed them. The trick is to make sure you have all tools close to hand so you minimise the movement of the hose once it is detatched from the lever.

    101North, the bit that needs tapping in is the insert, the olive is the round bit that goes over the hose.
  • 101_North101_North Posts: 607
    mister p wrote:
    I have done quite a few brakes without needing to rebleed them. The trick is to make sure you have all tools close to hand so you minimise the movement of the hose once it is detatched from the lever.

    101North, the bit that needs tapping in is the insert, the olive is the round bit that goes over the hose.

    Of course it is. Not concentrating when I was typing. I reckon it's fairly obvious which bit I meant though :wink:

    101
  • dan1502dan1502 Posts: 568
    I did mine yesterday. I needn't have bled them afterwards but did a full bleed of the rear and just a master cylinder bleed of the front. Doing the full bleed I introduced a bit of air early on through my fumbling so can't comment on that but when I did the front a small amount of bubbles came out.

    Do tell me how to do these 5 min bleeds though. I followed the shimano instructions with syringe, bag, top cup etc.
    Santa Cruz Tallboy
  • rhextrhext Posts: 1,639
    dan1502 wrote:
    I did mine yesterday. I needn't have bled them afterwards but did a full bleed of the rear and just a master cylinder bleed of the front. Doing the full bleed I introduced a bit of air early on through my fumbling so can't comment on that but when I did the front a small amount of bubbles came out.

    Do tell me how to do these 5 min bleeds though. I followed the shimano instructions with syringe, bag, top cup etc.

    Don't know about 5 minutes, and I await with trepidation the experts coming on to tell me this is not a good way to do it, but I didn't bother with the bag, top cup etc. I used two syringes: attach first one to caliper and suck the old fluid out, remove, attach second one to caliper and push the new fluid back in. Simple, straightforward, probably took 10 to 15 minutes, but I suspect with practice I'd get it down to less than 10.
  • 101_North101_North Posts: 607
    I guess it was me who introduced this 5 minute thing! I was referring to the quick bleed needed after shortening the hose - maybe that wasn't clear. As any air introduced to the system will be at the lever end (provided the lever isn't pulled first) all that is needed is to connect a syringe to the caliper end and push some fluid through to the reservoir and then top up the system. Not a full bleed and takes a matter of minutes.

    101
  • hounslowhounslow Posts: 153
    if it helps, i shortened the hose of the replacement slx madison sent me, and in the process it turned it from a spongey, flexy mess into a spot on brake, no bleed needed.
  • dan1502dan1502 Posts: 568
    101_North wrote:
    I guess it was me who introduced this 5 minute thing! I was referring to the quick bleed needed after shortening the hose - maybe that wasn't clear. As any air introduced to the system will be at the lever end (provided the lever isn't pulled first) all that is needed is to connect a syringe to the caliper end and push some fluid through to the reservoir and then top up the system. Not a full bleed and takes a matter of minutes.

    101

    Understood. I did that with the front but with the rear (probably stupidly) did a full bleed.
    Santa Cruz Tallboy
  • rubezrubez Posts: 323
    I'll just jack this thread, if I may.

    For shortening the hoses, where can I find the little yellow thing that comes apart in half, that looks like a pencil sharpener?

    14.jpg

    It is referred to here as a 'Shimano hose tool', what is the real name of them? Can you buy these anywhere?

    Cheers.
  • Pesky JonesPesky Jones Posts: 2,986
    Only way I know how to get them is to buy a shimano brake, but im sure they are sold seperately somewhere
    :D:lol::)cooldad :shock: :? :cry:
  • rubezrubez Posts: 323
    Hmm... well it says you can do it without them, just try it that way I suppose.

    What I don't get is why (when you cut the hose) brake fluid doesn't come flying out? - It even says you can hold the hose vertically or HORIZONTALLY while cutting... surely horizontally would have brake fluid come out, with the forces of gravity at play?!

    Is it safe as long as I keep the calliper lower than the top of the hose?

    Is the entire hose filled with fluid? I'm under the impression that the cut away section of hose (top part) will contain fluid... no?
  • raldatraldat Posts: 242
    I did mine a few months back. I worked just fine (sort of). No fluid came out except from the bit I cut off. When put back together the brakes worked well and felt good.

    BUT, when I turned the bike upside down on the trail to repair a flat tyre air in the reservoir crept into the lines and I had to pump the brakes to get them to work again. They were then fine until turned upside down again. No big issue but after a while I got tired of it and bought a bleed kit and bled them. Since then they feel exactly the same, but I can turn it upside down and they work right away after.

    So my experience, yes it works but there is a compromise. Bleeding is dead easy and worth the effort.
  • cooldadcooldad Posts: 32,904
    rubez wrote:
    Hmm... well it says you can do it without them, just try it that way I suppose.

    What I don't get is why (when you cut the hose) brake fluid doesn't come flying out? - It even says you can hold the hose vertically or HORIZONTALLY while cutting... surely horizontally would have brake fluid come out, with the forces of gravity at play?!

    Is it safe as long as I keep the calliper lower than the top of the hose?

    Is the entire hose filled with fluid? I'm under the impression that the cut away section of hose (top part) will contain fluid... no?
    Why should it, it's not under pressure.
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  • bikaholicbikaholic Posts: 350
    rubez wrote:
    Hmm... well it says you can do it without them, just try it that way I suppose.

    What I don't get is why (when you cut the hose) brake fluid doesn't come flying out? - It even says you can hold the hose vertically or HORIZONTALLY while cutting... surely horizontally would have brake fluid come out, with the forces of gravity at play?!

    Is it safe as long as I keep the calliper lower than the top of the hose?

    Is the entire hose filled with fluid? I'm under the impression that the cut away section of hose (top part) will contain fluid... no?


    You can easily make the hose clamp blocks - all you need to do is cut a v-channel into two small blocks of wood with a stanley blade.

    Atmospheric pressure is what's keeping the fluid inside the hose and the lever. Remember the trick that your science teacher did with the upturned glass of water? Well, the narrower the glass, the less likely is it for the water to pour out - the same applies when you put your finger over a drinking straw in a glass of liquid.

    The Shimano hose shortening method compensates for any little spillages when cutting the hose - that is the point of pumping out the pistons before cutting.
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