Author [NL] [FR] [ES] [DE] [SE] [IT] Topic: why does one front caliper have 2 brake lines but not the other?  (Read 1329 times)

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  • Offline pohm66

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    Offline pohm66

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    • Bike: 2014 TTSE
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    why does one front caliper have 2 brake lines but not the other?
    on: Jul 23, 2020, 03.19 am
    Jul 23, 2020, 03.19 am
    Asking as the small pistons on the 2 line side aren't working and giving me a brake shudder very similar to the brake rotor symptoms.

    Trying to diagnose if it is a brake line issue or if BOTH small pistons happen to be seized. The large pistons work fine.

    Thanks......
    Paul
    Currently 2014 Pacific Blue TTSE & 1994 Speed Triple
    Previous Trumpy's
       95 Speed Triple
       69 Trophy Custom in rigid frame (built not bought)

  • Offline bobv07662

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    Offline bobv07662

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    Re: why does one front caliper have 2 brake lines but not the other?
    Reply #1 on: Jul 23, 2020, 03.46 am
    Jul 23, 2020, 03.46 am
    They are hooked up to your rear brake hydraulics. Part of the linked brake system.
    1978 Bonneville    1973 Trophy Trail TR5T
    2012 Thruxton      1976 Hodaka ED250
    2014 Trophy SE    1950 Vincent Rapide
    1976 Yamaha RD400C 1969 Rickman 8 valve
    1978 Yamaha DT400E

  • Online Coconut   gb

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    Re: why does one front caliper have 2 brake lines but not the other?
    Reply #2 on: Jul 23, 2020, 07.39 am
    Jul 23, 2020, 07.39 am
    When you say "not working" - Check again when pressing the Rear brake pedal,
    to activate the Linked system mentioned below by bobv07662.

    Service Manual description of Linked Brake system :

    Linked Braking system

    This motorcycle is equipped with the Triumph Linked Brake System,
    combined with the Anti-Lock Brake System ( ABS ).

    In this system the rear brake is linked to the two lower pistons
    in the front right hand brake caliper.

    Operating the rear brake pedal will partially operate the front brake,
    allowing for balanced braking under all riding conditions.

    Operating the front brakes via the front brake lever will NOT operate the rear brakes.

    The rear brake circuit contains a proportional control valve
    ( located under the left control plate ) which limits the pressure
    to the rear brake once weight transfer to the front wheel begins.

    The linked front brake circuit contains a pressure delay valve which
    delays the application of the front brake  during initial application.


    Cheers  :821:


  • Offline pohm66

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    Offline pohm66

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    Re: why does one front caliper have 2 brake lines but not the other?
    Reply #3 on: Jul 23, 2020, 09.59 am
    Jul 23, 2020, 09.59 am
    Has always Coconut you are a walking encyclopedia on all things Trophy.... amongst other things I am sure  :028:.

    I'll have another check probably tomorrow... rear break is feel long a tad spongy so maybe time for a bleed.

    Thanks.......
    Paul
    Currently 2014 Pacific Blue TTSE & 1994 Speed Triple
    Previous Trumpy's
       95 Speed Triple
       69 Trophy Custom in rigid frame (built not bought)

  • Online Coconut   gb

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    Re: why does one front caliper have 2 brake lines but not the other?
    Reply #4 on: Jul 23, 2020, 09.05 pm
    Jul 23, 2020, 09.05 pm
    A couple more things ......

    Bleeding the Brakes isn't a straightforward operation, due to the ABS system.

    To fully bleed the brake system, the ABS Pump valves need to be opened while bleeding.
    This can be done by a Dealer using their equipment - plugged into the Diagnostics connector,
    or by use of an after market device such as "DealerTool".

    With regards to the "shudder" you describe, other than the Calipers and Discs,
    also check the condition of the front tyre for any cupping,
    and the condition of the front wheel bearings, both of which could be the culprits.

    Cheers  :821:


  • Offline pohm66

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    Offline pohm66

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    Re: why does one front caliper have 2 brake lines but not the other?
    Reply #5 on: Jul 26, 2020, 06.04 pm
    Jul 26, 2020, 06.04 pm
    Shudder seems to be tyre scalloping aka cupping... my old faithful tyre gauge seems to have been running a few PSI low so now have out of shape tyres.
    Paul
    Currently 2014 Pacific Blue TTSE & 1994 Speed Triple
    Previous Trumpy's
       95 Speed Triple
       69 Trophy Custom in rigid frame (built not bought)

  • Offline 1675   gb

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    Offline 1675

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    Re: why does one front caliper have 2 brake lines but not the other?
    Reply #6 on: Jul 26, 2020, 06.09 pm
    Jul 26, 2020, 06.09 pm
    If you have excessive rear pedal travel, also check that the pistons in the rear caliper and right lower caliper are operating freely. Also check the rear caliper is free to move on its pins.

     



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