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Too much travel on brake lever

danlightbulbdanlightbulb Posts: 658
edited October 2018 in MTB workshop & tech
Hi all,

I must have done this before but just checking. My brake levers have too much travel before they bite. I think as the pads have worn down a little the travel has got worse. Ive tried adjusting the reach screws on the lever which helped but then it puts the lever a bit too far out.

I just need to firm up the lever a bit. Im sure new pads would do it but there is still life left in these ones. Is it a case of dripping some extra fluid in?

The brakes are Sram guide r.

Thanks

Posts

  • They may need a bleed. I've just bled some 7 year old Tektros and they are now about as good as they ever were. (Which never was very good!)
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  • Also, if you do add fluid, don't just put in the DOT4 brake fluid you got for your car. Most MTB brakes use mineral oil. Brake fluid will possibly kill the seals.
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  • sniper68sniper68 Posts: 2,899
    kirkymtb wrote:
    Also, if you do add fluid, don't just put in the DOT4 brake fluid you got for your car. Most MTB brakes use mineral oil. Brake fluid will possibly kill the seals.
    SRAM Guide use Dot 5.1 fluid.If they’re like all other Avid brakes you can’t just pour a bit in you need to use syringes from the bleed kit.Epic bleeds do a good kit far cheaper than Avid/SRAM.
    I thought it was only Shimano who use mineral oil?
    Hope,Avid,SRAM,Formula all use DOT fluid.
  • billycoolbillycool Posts: 833
    When my (Shimano) brakes did much the same thing I did 3 things:

    Full system bleed (The Epic kits are very good)
    New pads
    New rotors

    Turns out my rotors were quite worn and that really affected the bite point. Changing them had a very positive result.

    Not saying this is your solution but all of the above sorted mine out.

    As above - make sure you use DOT 5.1 fluid - (my Shimanos use mineral oil)
    "Ride, crash, replace"
  • steve_sordysteve_sordy Posts: 1,986
    What happens when you repeatedly pump the brake lever?

    If the problem goes away, and the brakes get firmer, you need a bleed.
    If not, not.
  • Pumping the lever makes no difference. They arent spongy at all, so i dont think its an air issue. Its the bite point of the lever, pulling too close to the handlebars. Bike is only couple months old. i thought the brakes were meant to self adjust for pad wear.
  • billycoolbillycool Posts: 833
    It's not rotor wear then! (assuming it's brand new)

    I'd go back to where you bought it from (if possible). Ask them to have a look. A lot of places will do a free aftersales `service`.

    Or buy Shimano - that's just my personal preference.
    "Ride, crash, replace"
  • figbatfigbat Posts: 680
    billycool wrote:
    As above - make sure you use DOT 5.1 fluid

    Why DOT 5.1 rather than DOT 4?
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  • JBAJBA Posts: 2,623
    SRAM recommend DOT 5.1 and that is what their brakes come filled with.
    Formula recommend DOT 4.

    Shimano are more sensible and use mineral oil.
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    And it all promised so so much”

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  • veronese68veronese68 Posts: 22,788 Lives Here
    figbat wrote:
    billycool wrote:
    As above - make sure you use DOT 5.1 fluid
    Why DOT 5.1 rather than DOT 4?
    DOT 5.1 has a higher boiling point than DOT4 which has a higher boiling point than DOT3. As the boiling point goes up it also becomes more hygroscpic, not normally a problem in bicycle systems as they are sealed. DOT fluids also strip paint so be careful when using them. They can be mixed, but may alter the feel of the system.
    Do not confuse DOT5 with DOT 5.1. 5 is silicone fluid and is incompatible with the others.
    Mineral as used by Shimano is comparatively inert, isn't hygroscopic, but cannot be used with DOT fluids.
  • danlightbulbdanlightbulb Posts: 658
    edited October 2018
    I have the right fluid and have bled brakes before, but as I said it doesn't feel like an air issue, just a bite point issue. These brakes don't have bite point adjust. I have the bleed kits so if its just a case of pushing a touch more fluid in to firm them up I can try that, but bleeding brakes is a bit of a finiky job so hence avoid if I can. Maybe a better way of describing it is too much lever throw.

    I don't really want to have the hassle of transporting the bike to where I bought it from, for such a minor issue anyway.
  • sniper68sniper68 Posts: 2,899
    If you put more fluid in on worn pads then you might find they rub/lock on when you fit new pads.Make sure you push the pads fully back and wedge something between them.
  • The RookieThe Rookie Posts: 27,747
    I have the right fluid and have bled brakes before, but as I said it doesn't feel like an air issue, just a bite point issue. These brakes don't have bite point adjust.
    Do you have a high pad to rotor clearance, so that a lot of lever travel is used up just getting the pads onto the disc?

    If so look up 'advancing the pads'.
  • 02GF7402GF74 Posts: 1,294
    Just for completeness, magura use what's called blood, basically green coloured mineral oil. Probably same stuff as shimano, well I've used it without problems
  • You can always remove the caliper from the disc.
    Press the brake lever a little bit, this will allow the pads to come closer together and when put back on the disc there is less distance for them to travel before they come in to contact, which means less lever travel.

    I done it on a set of SLX brakes for a friend and they move only 5mm before being solid.
  • I agree with the Rookie. It’s not a bleed issue, you need to advance the pads.

    I generally need to advance the pads on all of 3 my bikes with both Shimano and Avid brakes a couple of times during the life of the pads. More so if I’ve had the wheels in and out a few times.
  • AvoneerAvoneer Posts: 525
    Pump the brakes fast and hard several times.

    Pull the lever tight to the bar and then clamp it in place with a toe strap etc.

    Leave it over night.

    As mentioned, it's about advancing the pistons. Leaving them clamped "on" overnight allows the piston seals to settle in the more advanced position rather than trying to roll the piston back into the caliper body.
    "Campagnolo has soul, Shimano has ruthless efficiency and SRAM has yet to acquire mystique. Differentiating between them is a matter of taste"
  • steve_sordysteve_sordy Posts: 1,986
    I have not heard of advancing the pads before, so I Googled it. Hmmm, not easy to find. Eventually after quite a few attempts, I found this from SRAM

    https://www.sram.com/sites/default/file ... date_0.pdf

    For those that know all about this procedure, does this fit the bill?
  • AvoneerAvoneer Posts: 525
    Yes - it all achieves the same thing.

    The brakes need to be left "on" for a few hours though to let the seals settle.

    Pat.
    "Campagnolo has soul, Shimano has ruthless efficiency and SRAM has yet to acquire mystique. Differentiating between them is a matter of taste"
  • sniper68sniper68 Posts: 2,899
    I have not heard of advancing the pads before, so I Googled it. Hmmm, not easy to find. Eventually after quite a few attempts, I found this from SRAM

    https://www.sram.com/sites/default/file ... date_0.pdf

    For those that know all about this procedure, does this fit the bill?
    When I bought my Juicy 5s(2005/6?)advancing the pads was part of the fix and set up instructions.It was also featured in the manual for the Juicy Ultimate(7) that came on my 2008 Enduro.As things have gone more online/downloads etc this type of info tends to get lost :roll:
    AFAIK know you only need to do it with Avid/SRAM systems?I've never had to do it with Formula or Hope systems.
  • steve_sordysteve_sordy Posts: 1,986
    sniper68 wrote:
    ..................
    AFAIK know you only need to do it with Avid/SRAM systems?I've never had to do it with Formula or Hope systems.

    All except my last two bikes were Shimano and I had never heard of advancing the pads. I had no problems.
    My current and previous bike were SRAM Guide. The bikes did not come with any brake specific instructions, although I thought the first few rides were lacking in grip, despite bedding them in. Maybe I should have "advanced the pads"? :)
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