Results 1 to 25 of 25
  1. #1
    Rep'n the 905
    Reputation:
    Join Date
    Jun 2012
    Posts
    265

    Mechanical Rear Disc Brake Consistant Failure....but why?

    I'm going to try and explain this as best I can without pictures, hopefully someone here can help me and understand what I'm saying!

    I have a few years old Specialized hardrock. It has mechanical disc brakes. This is my first real season of riding and I've gone out I'd say 2-3 times a week now for several months. My rear brake has been disastrous for me for the last month or so. I've taken it to my LBS once I noticed it wasnt as strong as at the start, all they did really was pull the cable, and move the little arm that applies the brakes up. That seemed to do the trick, until after another few rides it came loose again. So pull the little cable and move the arm again. Then one ride, as I'm going down, I apply the rear brake and I hear a click, and the rear brake is basically not working. I test it again, and same thing only this time it just completely gives out, no rear brake at all. I pull the brake lever and it makes a clicking sound (the sound is coming from the brake component not the lever) and just no stopping power at all. So I got back to my LBS store tell them I dont know what the problem is, but I'd like it fixed, they say sure. Takes the guy 10mins, says $15 for the labour and I'm good. In my head I dont feel like he fixed the problem, he just got it working again. It did work but the pressure in the lever was very minimal, as I could almost pull the lever to my handle bar. So it hasn't completely failed on me again but I'd say I get about 20% braking power from the back right now, its pretty much useless. And my LBS "fixed" my problem by pulling the cable back more and that little arm that raises now touches the rest of the braking component when I full engage the brake.

    I've been told its not the pads, there still is enough on them that I shouldnt have to replace them yet. I feel like the brake mech is broken internally or something, like something is slipping on the inside.

    Can anyone assist me or is what I said impossible to figure out without seeing it in person or pictures? I'd go back to my LBS store but I dont feel like they want to fix the problem fully.

  2. #2
    rebmem rbtm
    Reputation:
    Join Date
    Apr 2007
    Posts
    3,168
    What brand and model is the brake?

  3. #3
    mtbr member
    Reputation:
    Join Date
    May 2006
    Posts
    11,333
    You do know that mechanical brakes need the inside pad adjusted outwards as the pads wear????

    They are not self adjusting.

  4. #4
    Rep'n the 905
    Reputation:
    Join Date
    Jun 2012
    Posts
    265
    Quote Originally Posted by jeffscott View Post
    You do know that mechanical brakes need the inside pad adjusted outwards as the pads wear????

    They are not self adjusting.
    No I did not know that, but I would hope the 2 different bike shops I went to to fix this issue did. There the ones who did the maintenance on the brakes, not me. But thanks, now I do know that.


    And my brakes are the amazing Shimano Tektro IOX
    [img]http://shop.dolekop.com/product_images/898.jpg[/image]

  5. #5
    Merendon Junkie
    Reputation: abelfonseca's Avatar
    Join Date
    Dec 2011
    Posts
    510
    That exact same thing happened to me with the rear tektro novela on a spesh Hardrock I used to own. It is an internal problem with the caliper. The caliper uses 3 ballbearings that run on 3 ramps. When you press the lever the ramps move, and the bbs push outward against the shallow part of the ramps. For some reason, which I suspect has to do with to high tolerances in the manufactuting process, the bbs will sometimes "jump" into the next ramp and land and the deep part of it. Hence the click and total loss of braking power. It seems to happen when the bbs have worn a little and it doesnt happen in every caliper. My front novela never had this issue and its the one that gets used the most often and the hardest. I replaced the 3 bbs with new ones and put some new grease in. The issue was solved. About 8 months later it happen again with the new owner of the bike. I changed the bbs for a second time and the brake is stopping once more. I dont know how much it will last.

    As for your first issue, the answer is YES. Mech disk brakes require constant adjustments. I used to adjust mine almost after every ride if wanted to keep them working at their best.


    Saludos!

  6. #6
    Rep'n the 905
    Reputation:
    Join Date
    Jun 2012
    Posts
    265
    So whats my best way to fix this problem permanently?

  7. #7
    mtbr member
    Reputation:
    Join Date
    Aug 2008
    Posts
    3,550
    Get better brakes.
    BTW, Shimano doesn't make that brake. Tektro does.

  8. #8
    mtbr member
    Reputation:
    Join Date
    Oct 2009
    Posts
    228
    Quote Originally Posted by BigGK View Post
    So whats my best way to fix this problem permanently?
    Buy hydraulic brakes.

  9. #9
    mtbr member
    Reputation: cbell3186's Avatar
    Join Date
    Jul 2009
    Posts
    41
    If cost is a concern go with avid bb7s, extremely economical, good stopping power but if it's "about time for an upgrade" then hydraulics are the way to go....

  10. #10
    Rep'n the 905
    Reputation:
    Join Date
    Jun 2012
    Posts
    265
    Yea I figured as much, I'm trying to hold out for an entire new bike. So I didnt really wanna spend too much more on this bike, but i may have to look into a new setup. Thanks!

  11. #11
    mtbr member
    Reputation:
    Join Date
    Mar 2012
    Posts
    67
    Yeah, abelfonseca probably right, I have serviced those brakes a bunch of times and it usual ends up being a "step up bearing" issue, one of the bearings becomes worn, out of round, so no matter how much force you apply they won't hold because one of the "step up bearings" have become out of round. You can easily fix it by taking the caliper apart and replacing the bearings, some versions have (1) bearing, others have (2) bearings and then some have (3) bearings. But all of them are 1/4 bearings. The standard bearings are cheap ss/g100 bearings, so when you replace them use chrome stainless steel, with at least a grade 25, and then those calipers will last forever. But I would upgrade my brakes at least to BB7, as they never seem to "break"!

  12. #12
    mtbr member
    Reputation: cbell3186's Avatar
    Join Date
    Jul 2009
    Posts
    41
    Quote Originally Posted by BigGK View Post
    Yea I figured as much, I'm trying to hold out for an entire new bike. So I didnt really wanna spend too much more on this bike, but i may have to look into a new setup. Thanks!
    OK, if this direction, and same style bike for future, what if you upgrade to hydros, then when purchase time for new bike comes, either a) take off said hydros and retire old bike or b) swap newer not so great stock brakes with previously purchased, better hydros?

  13. #13
    mtbr member
    Reputation: Econoline's Avatar
    Join Date
    Mar 2004
    Posts
    375
    Quote Originally Posted by BigGK View Post
    So whats my best way to fix this problem permanently?
    Avid BB7 Mech Disc Brake Grey Fnt/Rer 2011 at Price Point

  14. #14
    Rep'n the 905
    Reputation:
    Join Date
    Jun 2012
    Posts
    265
    Thanks all, I'm thinkin about going budget for this time, BB7's. Unless a used set of hydro's comes up first.

  15. #15
    mtbr member
    Reputation: Econoline's Avatar
    Join Date
    Mar 2004
    Posts
    375
    Quote Originally Posted by BigGK View Post
    Thanks all, I'm thinkin about going budget for this time, BB7's. Unless a used set of hydro's comes up first.
    You could just replace the rear brake with a BB7 for now and see how you like it. No need to replace the front now if it's working well.

  16. #16
    gran jefe
    Reputation:
    Join Date
    Nov 2011
    Posts
    3,088
    Quote Originally Posted by BigGK View Post
    Thanks all, I'm thinkin about going budget for this time, BB7's. Unless a used set of hydro's comes up first.
    i'd much rather have bb7s than any used hydros at the same price.

  17. #17
    rebmem rbtm
    Reputation:
    Join Date
    Apr 2007
    Posts
    3,168
    Quote Originally Posted by Econoline View Post
    You could just replace the rear brake with a BB7 for now and see how you like it. No need to replace the front now if it's working well.
    If the OP was only going to replace one brake caliper with a BB7 it'd be better to put the current front brake on the rear and put a BB7 on the front.

  18. #18
    addicted to chunk
    Reputation: Shark's Avatar
    Join Date
    Feb 2006
    Posts
    5,235
    Yup, bb7's!
    Riding.....

  19. #19
    Always Learning
    Reputation: BruceBrown's Avatar
    Join Date
    Jan 2004
    Posts
    8,981
    Quote Originally Posted by BigGK View Post
    Thanks all, I'm thinkin about going budget for this time, BB7's. Unless a used set of hydro's comes up first.
    Comb eBay for used BB7's. You should be able to get a pair for a song.

  20. #20
    Rep'n the 905
    Reputation:
    Join Date
    Jun 2012
    Posts
    265
    There seems to be an overwhelming response for the BB7's, even when I go to websites that sell em new, theres tons of reviews and there pretty much all great. I think its the way to go, just hoping I can get one for cheap!

  21. #21
    Rep'n the 905
    Reputation:
    Join Date
    Jun 2012
    Posts
    265
    Quote Originally Posted by cobba View Post
    If the OP was only going to replace one brake caliper with a BB7 it'd be better to put the current front brake on the rear and put a BB7 on the front.
    Really? I'm prolly really inexperienced so what I do when riding is prolly not optimal but I seem to use the rear brake much more then the front, so I assumed I would want to have the better brake on the rear???

  22. #22
    mtbr member
    Reputation:
    Join Date
    Sep 2012
    Posts
    202
    shimano XT785's... Sounds like you ride a decent amount-- So why jack around with something your using (10xper min average on a 3hour ride=1800) 1800 times on a decent ride(hmmm that sounds high-- but you get the idea)... If you using anything that much-- you should find a way to get the part that makes that much use more enjoyable...so treat yourself to some hydraulic high stopping power low fade goodness..

  23. #23
    Rep'n the 905
    Reputation:
    Join Date
    Jun 2012
    Posts
    265
    Quote Originally Posted by SB Trails View Post
    shimano XT785's... Sounds like you ride a decent amount-- So why jack around with something your using (10xper min average on a 3hour ride=1800) 1800 times on a decent ride(hmmm that sounds high-- but you get the idea)... If you using anything that much-- you should find a way to get the part that makes that much use more enjoyable...so treat yourself to some hydraulic high stopping power low fade goodness..
    I agree completely, and I wouldnt even hesitate but I'm seriously planning on a new ride within the next month. Theres a bike show in my area in about a week that I'm holding out for, so I just need something to fill the gap.

  24. #24
    Owl
    Reputation:
    Join Date
    Oct 2012
    Posts
    33
    From my experiences, Tektro IOX are just horrible brakes. I've only had 1 encounter with them when they came on a low end XC bike. I had to readjust them after every ride, and eventually the actuation arm actually sheared off from the caliper unit. Being a cheap bike, I replaced them with with the hydraulic Tektro Auriga Pros (got em got a great deal on the takeoff wall from the LBS). BB7s are probably the only decent mechanical brakes I've ever used.

  25. #25
    mtbr member
    Reputation: tucoramirez's Avatar
    Join Date
    Aug 2012
    Posts
    94

    try BB7s and Avid levers

    Quote Originally Posted by BigGK View Post
    So whats my best way to fix this problem permanently?
    buy BB7s, Tektro is a horrible brand, sorry Avid BB7 Mech Disc Brake Grey Fnt/Rer 2011 at Price Point hope you are willing to install them since it is poor form to buy parts online and ask the LBS to install.They tend to be more difficult to install and maintain than a good hydra brake.I have had both since 2004,XT, SLX,LX and BB7s.BB7s are better than some poorly designed hydras...like low end Hayes poop.

Posting Permissions

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