Quantcast

Frankenbrakes and brake improvement discussion

Discussion in 'Downhill & Freeride' started by Udi, Sep 2, 2015.

  1. Sandwich

    Sandwich just shake your rump
    Staff Member

    Rep/Likes:
    50 / 444
    Joined:
    May 23, 2002
    Messages:
    14,546
    Location:
    01776
    From people that say things, it sounds like the brakes only last a couple of seasons before seals wear out and your brakes start sucking air. udi rants about a plastic bit in the master cylinder and kidwoo talks about a leaking, no-replaceable piston seal, so the choice is yours as to why the brakes start sucking. I have a pair of XTs that are good but the first few initial squeezes always have that pump up.

    As for replacing them, I'd say you'd have a hard time finding a cheaper and better lever set than the SLX/zee levers for $24 from jenson that are always brought up. I wouldn't recommend the levers from magura but you might be able to score some sort of apparatus off of ebay. Formula makes mineral oil levers now, but it might be a challenge to get them and to make them work with the large piston surface area of your zee calipers.

    It might be wiser to think about a complete set of brakes, and move on to something that people hate the least.
     

    Please register to disable this ad.

  2. StiHacka

    StiHacka Compensating for something

    Rep/Likes:
    262 / 2,114
    Joined:
    Jan 4, 2013
    Messages:
    7,414
    Location:
    i͓̽t͓̽ i͓̽s͓̽ fu͓̽l͓̽l͓̽ o͓̽f s͓̽t͓̽a͓̽r͓̽s͓̽
    I solved my sucky Shimano and Magura brakes by mating Shimano (Saint) levers to Magura (MTS) calipers. MT-8 could not be salvaged by any sorcery as both the levers and the calipers are flexy. I believe doing the alternative (Mag levers, Shi calipers) brings the worst of both worlds together in a tightly confined space and might cause our universe to assplode.
     
    • Useful Useful x 1
  3. KAZHA

    KAZHA Chimp

    Rep/Likes:
    4 / 3
    Joined:
    Feb 20, 2015
    Messages:
    18
    Location:
    Flat AF
    What about newer gen XT/SLX levers, are they any good, or same shit in different colour?
     
  4. Udi

    Udi RM Chief Ornithologist: “I Brake for Birds”

    Rep/Likes:
    70 / 559
    Joined:
    Mar 14, 2005
    Messages:
    4,368
    The second thing you said.
    They changed the lever/MC but the problems remain.

    Just buy new Zee levers.
    My buddy rides Zee brakes and buys a brand new set of levers every season. It seems to keep them working decent.

    Shimano's 4-pot calipers are less prone to seal problems than the 2-pot ones (I don't know why - Shimano probably doesn't either), so Saint and Zee problems are usually at the lever end.

    Definitely don't buy Magura levers, they have plasticky rubbish build quality and the ergonomics are poor.
     
  5. KAZHA

    KAZHA Chimp

    Rep/Likes:
    4 / 3
    Joined:
    Feb 20, 2015
    Messages:
    18
    Location:
    Flat AF
    Thanks for information and new ZEE lever it is then.
    Although maybe I have discovered something that fixes the "spongy first pull" lever issue - I put a small brass washer between the lever cap(3) and seperator(4) unit (http://si.shimano.com/pdfs/ev/EV-BL-M640-3431.pdf), then purged the system from caliper and the lever seems fine for a couple of days. But maybe I just got lucky
     
    #485 -   Dec 10, 2017 at 1:18 PM
    Last edited: Dec 10, 2017 at 1:25 PM
  6. Udi

    Udi RM Chief Ornithologist: “I Brake for Birds”

    Rep/Likes:
    70 / 559
    Joined:
    Mar 14, 2005
    Messages:
    4,368
    Yes, I don't think that's a good idea because it's likely increasing the sealing force of the reservoir cap / bladder - which would allow more fluid to stay in the system (the bladder seal is designed to allow excess to leak out easily, it's a very low-pressure seal) which increases the risk of operating as a closed-system (i.e. no longer volume compensated under temperature-driven fluid / seal expansions).

    The improved sealing may be fixing whatever issue was causing the spongy first pull, but I think on Shimano when problems start it's safest to install new lever assemblies. If it is within your budget, after 4-5 seasons I would be replacing both L/R, but up to you obviously.
     
  7. KAZHA

    KAZHA Chimp

    Rep/Likes:
    4 / 3
    Joined:
    Feb 20, 2015
    Messages:
    18
    Location:
    Flat AF
    Yeah,I was just curious, because there would be a constant drops of oil under the rubber boot thing,that covers the hose entering the lever.
    Anyway,new levers for new season is must!