Soft Front Brake Pull

Discussion in 'Wheels' started by glider., Apr 27, 2008.

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Post what brake fluid you use

  1. DOT 5.1

    0 vote(s)
    0.0%
  2. DOT 5

    58 vote(s)
    57.4%
  3. DOT 4

    41 vote(s)
    40.6%
  4. DOT 3

    2 vote(s)
    2.0%
  1. glider.

    glider. BOT Machine

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    Many people here have been complaining about a softer than normal front brake pull on their bikes.

    Let's all weigh in here and see what brake fluid you are running if it is all DOT 5 or if some are having this problem using DOT 4 also.

    Also a few other choices as well.

    Feel free to leave any comments also.
     
    Last edited by a moderator: Nov 12, 2013
  2. Fisher

    Fisher Account Removed

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    Many times when I see this it's dirty caliper/pistons causing the pistons to cock in the bore and not releasing properly.A good cleaning with an old toothbrush and brake fluid usually restores the feel/action.Do not use brake cleaner,that stuff's murder on seals.The new Brembo calipers won't have that problem as much.Yay!:D
     
  3. ProF

    ProF Junior Member

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    On my recently acquired 03 RG, the lever moves about half way to the bar before it starts braking. Once reaching that point, the braking is fine. The total travel isn't too great; I cannot get all the way down to the bar even if I squeeze hard. There is no spongy feeling like air, nor does pumping the lever change anything. The reservoir is full as well. I'm using DOT 5. On my 86 FXRS, the lever moves about an eighth of an inch before braking begins. ????
     
  4. glider

    glider Veteran Member

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    The DOT 5 will compress more than others and the reason for the change back to DOT 4 on the newer bikes with ABS brake systems. The DOT 4 will give you a better brake feel at the lever.
     
  5. Fisher

    Fisher Account Removed

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    DOT 5 aerates too easily when pulsed at speeds the ABS is capable of.Brembo required the switch to DOT 4.
     
  6. krikket

    krikket Active Member

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    There could be a number of contributing factors to that. However, brake fluid itself shouldn't be the culprit unless there is air in the system because no matter what kind of liquid it is, it cannot be compressed. Gas (air) compresses, but not liquids.

    Some other factors could be in the caliper design. Caliper pistons retract because of the seal design. If the seal design has the piston(s) pull back a little further, that might give you a softer feel. Also, brake hoses flex. My Night Train has I think a 30" hose to the front caliper. Just some observations from an ex-auto mechanic.
     
  7. deucedog

    deucedog Active Member

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    DOT 4

    I had to replace my rear caliper last year due to a lock up at hiway speeds.

    I just couldn't get it to bleed properly so I went to Harbor Freight and got the small vacumm brake bleeder kit. It's just a couple of lengths of hose, a small container and a hand vacuum pump. I hooked it up to the caliper,put a small bit of vacuum on it and slowly opened the bleeder. I did this about 4 times, until new fluid came out of the bleeder. My rear brake is now almost immediate and has no softness or spongy feel to it. I'm replacing the front caliper shortly and will bleed it the same way.

    http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92474
     
  8. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    I'll bite...what is Dot 5.1 and referenced to HD? Guess I haven't been paying attention...
     
  9. glider

    glider Veteran Member

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  10. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    So DOT5.1 is compatible with Etylene-Glycol DOT 3 & 4 Fluids...where do you get it, is it color coded or by virtue it is not purple it is amber colored to imply it is "mixable". Do I take 5.1 implies that it has even higher boiling point than DOT4, but is not Silicone based like straight DOT5 "Purple"? When using DOT 4 I would use Castrol in the big bottle, as it was used on my truck & car, to flush all the systems every 3 years.