Advertise on Bikeforums.net



User Tag List

Results 1 to 10 of 10
  1. #1
    Senior Member ApolloCVermouth's Avatar
    Join Date
    Jul 2005
    Location
    Toronto
    My Bikes
    homemade cyclocross, 2005 KHS Flite 100 frame + assorted parts
    Posts
    140
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Single pivot brake issues...

    I'm running nashar bulhorns, nashbar bar-end levers, and an old shimano 600 single pivot road brake as a front brake on my fixed gear. It won't spring back on its own anymore. The cable isn't that old. Ideally I would just buy a new dual pivot brake but this isn't an option at the moment. Part of the problem may be that the brake was designed for old style road brakes and that routing the cable along the inside of the bullhorn just produces too much friction. Maybe there is a better way of routing the cable. I have noticed that the brake stiffens up after it rains and some chain lube makes things better for a while. My question is this: Can I clean and rebuild this brake? What are the options I should try to get this brake to work properly? Thanks.

  2. #2
    Member
    Join Date
    Jul 2006
    Location
    Berkeley/Santa Cruz
    My Bikes
    HPL steel track, Marin Muirwoods, 1985 Aluminum Trek 2000(?)
    Posts
    47
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Can you describe the problem in more detail?
    Does one pad remain against the rim as you release the lever?
    Have you tried stressing the spring/replacing it?
    Did you lube the spring, pivots, cable?

    The cable routing you describe should not affect brake function.
    2003 Marin Muirwoods/Human Propulsion Laboratory custom track/2007 Trek 5000 (Ultegra and FSA)
    sR+++!% bR2HF rERTCP! raR5 ld+km so++ aC vP21/C16 c++ m++% bb+ rSH rRI rPR rFG rDE rTR rGL rWW rIHC i++

  3. #3
    cs1
    cs1 is offline
    Senior Member cs1's Avatar
    Join Date
    Feb 2004
    Location
    Clev Oh
    My Bikes
    Specialized, Schwinn
    Posts
    6,195
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Did you check to see if the brake springs aren't broken? Springs do get soft and loose some of their spring, for lack of a better term, over time. I'm not really sure if a dual pivot will help. You might want to take everything apart and do a thorough clean and lube. Good luck

    Tim
    1999 Waterford RSE-11, 1995 Waterford 1200, 1989 Specialized Rockhopper Comp
    1989 Raleigh Technium, 1989 Schwinn Traveler, 1986 Specialized Rockhopper
    1984 Specialized Stumpjumper, 1986 Specialized Stumpjumper and just way too many projects to list.

  4. #4
    Your mom
    Join Date
    Aug 2006
    Posts
    2,546
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    When you clean and lube, which you should, pull the two arms of the spring further apart. This will make the action of the spring more pronounced. Do the Nashbar levers have returns springs in them? If not, a set of levers with springs will help with lever return and more positive action.

  5. #5
    ride, paint, ride simplify's Avatar
    Join Date
    May 2005
    Location
    San Diego
    My Bikes
    Cannondale R300 Caad2
    Posts
    1,202
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by ApolloCVermouth
    My question is this: Can I clean and rebuild this brake? What are the options I should try to get this brake to work properly? Thanks.
    Yes you can! They're very simple to take completely apart, and you can then clean all the parts and reassemble. This may not be necessary though, if you just use the end nut to reduce the pressure being exerted on the arms, pinching them against each other at the pivot point. You want just enough pressure so there is no front-to-back play (when you grasp the brake pads, and move them front-to-back in opposite directions, you don't want to feel looseness or play). But if there's too much pressure, the arms can't move freely and they bind up, like yours are doing. Those old 600 single-pivots are very nice brakes, and the springs very seldom get too weak to function. I'd sure try the lube and adjust procedure, and if that doesn't work, take it apart and clean it thoroughly and try again, before giving up on it. Here's a link to the ParkTool description of this adjustment that I described (illustrations may help). Scroll down to below half way, to where it says "Sidepull Caliper Arm Adjustment".
    http://parktool.com/repair/readhowto.asp?id=22

  6. #6
    The Improbable Bulk Little Darwin's Avatar
    Join Date
    Jul 2005
    Location
    Wilkes-Barre, PA
    My Bikes
    Many
    Posts
    7,294
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Single pivot brakes are EASY to service.

    Once you get it off the bike, use a pair of pliers to release the spring, then take off the two nuts on the pivot (retainer nut and capped lock nut) and notice how things come apart. clean real well, and lube as you put it together. I use Triflow lube when I am assembling my brakes, and so far it does well. I don't ride in the rain, if I did I would probably use grease.

    I also remove the pads when doing the cleaning, lubing and assembly just to keep from accidentally lubing the pads.

    For the tension on the pivot nut during assembly, I tighten until it starts to bind, then back off very slightly (about 1/8 turn) then put on the lock nut. It may take a couple of tries to get free motion along with minimum flex. If you are too tight it binds, if you are too loose, you get excessive flex. You can detect the flex by taking an arm of the caliper in each hand, and applying a little twisting pressure. Play with it until you get free motion with a minimum of movement. (as the previous poster suggested... the same process works on or off the bike).

    Of course, with all this said... your first check should be to remove the cable and see if the brake binds. If not, then whether the cables are fairly new or not, there might be an issue related to the cable... look for burs at the ends where the housing was cut, or places where the cable may have been folded which caused a crimp.
    Slow Ride Cyclists of NEPA

    People do not seem to realize that their opinion of the world is also a confession of character.
    - Ralph Waldo Emerson

  7. #7
    biked well well biked's Avatar
    Join Date
    Jul 2005
    Posts
    6,796
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by lawkd
    Yes you can! They're very simple to take completely apart, and you can then clean all the parts and reassemble. This may not be necessary though, if you just use the end nut to reduce the pressure being exerted on the arms, pinching them against each other at the pivot point. You want just enough pressure so there is no front-to-back play (when you grasp the brake pads, and move them front-to-back in opposite directions, you don't want to feel looseness or play). But if there's too much pressure, the arms can't move freely and they bind up, like yours are doing. Those old 600 single-pivots are very nice brakes, and the springs very seldom get too weak to function. I'd sure try the lube and adjust procedure, and if that doesn't work, take it apart and clean it thoroughly and try again, before giving up on it. Here's a link to the ParkTool description of this adjustment that I described (illustrations may help). Scroll down to below half way, to where it says "Sidepull Caliper Arm Adjustment".
    http://parktool.com/repair/readhowto.asp?id=22
    +1.....lawkd has great advice here, definitely try the simplest thing first: try loosening the nut just a bit and see if it doesn't free up the spring action of the brake-

  8. #8
    me have long head tube TallRider's Avatar
    Join Date
    Oct 2005
    Location
    Chapel Hill, NC
    Posts
    4,097
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    older sidepull brakes like this Shimano 600 model (probably what you have?) actually have stronger return springs because they were designed to use with levers that don't have their own return springs.

    I doubt the problem is cable friction if you've taken good care of them - newer cable lined cable housing is smoother than what was available at the time these brakes were produced, anyway.

    If the spring is broken, new brakes would help. Dual-pivots don't have stronger return springs.

    But the advice of the last three posters is all good - you should service the brake, make sure that the pivot is clean and not too tight.

  9. #9
    Senior Member Retro Grouch's Avatar
    Join Date
    Feb 2004
    Location
    St Peters, Missouri
    My Bikes
    Rans Enduro Sport, Hase Kettweisel Tandem, Merin Bear Valley beater bike
    Posts
    23,728
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by ApolloCVermouth
    The cable isn't that old.
    How about the cable housing?

  10. #10
    Senior Member ApolloCVermouth's Avatar
    Join Date
    Jul 2005
    Location
    Toronto
    My Bikes
    homemade cyclocross, 2005 KHS Flite 100 frame + assorted parts
    Posts
    140
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thanks for all the advice. I've backed off the nut in front and the brake itself springs back well enough. I do think the problem is with the cable or housing. I will re-cable the brake paying more attentiong to getting as smoth a transition as possible. I may even run the cable out of the bar earlier rather than having it come out around near the stem.
    The bike has been out in the rain and that may have something to do with it. It's pretty damp here in Halifax.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •