fluid leak after brake pad change

Discussion in 'GS Boxers' started by Tslepebull, Oct 7, 2011.

  1. Tslepebull

    Tslepebull Snakecharmer

    Joined:
    Jan 15, 2006
    Oddometer:
    272
    Location:
    Tyler Texas
    I replaced the rear brake pads on my 05 GS today. They really needed it so the pistons were extended all the way out. After I pushed them back and replaced the pads I noticed what looked like brake fluid dripping out from under the tank and transmission. I had wrapped a rag around the brake fluid reservoir in case it leaked but this is not where it came from. The brakes with the new pads seem to work fine, I get no brake fault signal and there is no wet place on or underneath the ABS unit. Where was the fluid coming from and do I have a problem?

    This is one of the servo brake models so things are a bit more complicated.
    #1
  2. Mudcat

    Mudcat Unregistered

    Joined:
    Jul 22, 2004
    Oddometer:
    4,472
    Location:
    Bay Area
    The brake fluid was coming from your ABS servo unit. It had been over filled at some point, nothing to worry about. Just don’t let the fluid get on painted surfaces.
    Also, it sounds like you need a new rear rotor. I bet it is out of spec, that is why your caliper pistons are extending so far.
    #2
  3. Tslepebull

    Tslepebull Snakecharmer

    Joined:
    Jan 15, 2006
    Oddometer:
    272
    Location:
    Tyler Texas
    Thanks Mudcat. I made the same conclusion that the fluid was because I had pushed the pistons back in (the pads were completely gone). I can't find any evidence of wetness on the ABS unit but the drip was definately under it. My question is where did the fluid get out? I was concerned that if fluid could get out, air or water could get in. If there is a problem will I get an ABS fault?

    BTY I measured the rotor and it is still in spec; the pads were really really worn. The observation holes in the front were worn through. It has been nearly 40 K miles since I replaced the first set and I wouldn't have wanted to drive 100 more miles on them or I would have scored the rotors. I got lucky.

    I checked the front pads also and with nearly 60K miles they still look fine.
    #3
  4. Mudcat

    Mudcat Unregistered

    Joined:
    Jul 22, 2004
    Oddometer:
    4,472
    Location:
    Bay Area
    It came out the drains at the top of the ABS servo unit, they are just below the filler caps. They converge into one line going down the right side of the unit. Where it ends I could never tell.
    BTW overfilling the unit is not a problem, under filling it is.
    #4
  5. Tslepebull

    Tslepebull Snakecharmer

    Joined:
    Jan 15, 2006
    Oddometer:
    272
    Location:
    Tyler Texas
    Thanks again Mudcat. I had just found a post by JVB using the search function that referred to the overflow tube and this is exactly what I was seeing. I will go relax and drink a homebrew now. :freaky

    BTY Mudcat or (bullhead catfish) is also known as Ameiurus natalis for the yellow bullhead or Ameiurus melas for the black bullhead -- both common here in Texas. Not that most of the world beyond the American Fisheries Society cares.
    #5
  6. Mudcat

    Mudcat Unregistered

    Joined:
    Jul 22, 2004
    Oddometer:
    4,472
    Location:
    Bay Area
    Yes, overflow tube is a much better description then what I posted. JimVonBaden is very good.
    When you compress the caliper pistons this raises the fluid level in the ABS servo unit. If the unit had been overfilled some fluid will likely be expelled. This is relatively harmless.
    An indicator of low brake fluid in the ABS servo unit is a shut down of the ABS servo unit under hard braking. :eek1 Very unsettling and very dangerous.
    If you should ever drop your bike, especially on the right side, there is a substantial chance you have lost fluid from the servo.
    #6