1. Hello Guest. You have limited privileges and you can't "SEARCH" the forums. Please "Log In" or "Sign Up" for additional functionality. Click HERE to proceed.

Master cylinder issue?

Discussion in 'XJ Technical Chat' started by weoxstan, Jul 30, 2008.

  1. weoxstan

    weoxstan Member

    Messages:
    118
    Likes Received:
    0
    Trophy Points:
    16
    Location:
    Central Michigan
    What is going on? My front brakes are fine in the morning. I ride to the office and it sets all day in partly shaded area and when I leave the front brakes are starting to grab. This is before I do anything; start it, move, apply brakes. I go about 3 miles to workout and leave it parked in the sun for a couple of hours. When I go to leave the front wheel has difficulty turning. It is hard to push forward. I have been carring a small wrench to crack open the bleeder so that pressure is released, when I do this it is fine all the way home and good until the next afternoon. It seams like the fluid is expanding under the heat of the day but the master cylinder is not letting the pressure off the caliper.

    I have cleaned out from under the seal on the caliper and the junk behing the piston twice. This was about week apart, the last time was about 2 weeks ago. First time there was a lot of nasty stuff back there but the second time I only found a very small amount, probibly stuff left in the line. The second time I flushed the lines, to make sure there was nothing left.

    Any ideas?
     
    weoxstan, Jul 30, 2008
    #1
  2. Robert

    Robert Active Member

    Messages:
    7,479
    Likes Received:
    8
    Trophy Points:
    38
    Location:
    Ventura CA
    Your brake master cylinder is probably polluted with particulate matter from the rotting of the rubber brake line components and/or moisture.
    The fix is to rebuild the master cylinder and make sure the return port is clear. Use a fine copper wire to push throught the hole. Odds are, with your symptoms, you will find the port blocked.
    I'd also suggest rebuilding your calipers and replacing your brake lines at this time (they are all well past life expectancy and are probably contributing to your problem). I just had to sink $400 into new parts for my 82 for similar reasons. Start saving up and contact Chacal.
     
    Robert, Jul 30, 2008
    #2
  3. low-1-5-0

    low-1-5-0 Member

    Messages:
    230
    Likes Received:
    0
    Trophy Points:
    16
    Location:
    Newfoundland
    I had the exact problem with the maxim... just letting it sit in the shed it would grab to the point I couldn't move the bike...cleaned out the master many times and even rebuilt it once but it still grabbed... I ended up buying a new master off ebay a couple weeks ago... and it works great... brake hasn't grabbed once since

    http://cgi.ebay.ca/Front-Brake-Master-c ... dZViewItem

    if you do buy one remember there is no mirror mount though... and make sure you get the brake micro switch (they forgot to send mine, but sent it to me within the week)... and you're going to need a fine thread banjo bolt
     
    low-1-5-0, Jul 30, 2008
    #3

Share This Page