SRAM Guide RS Brakes - Lever slow to return

Discussion in 'Parts 'n Stuff' started by Jesterarts, Sep 16, 2016.

  1. Jesterarts

    Jesterarts Likes Dirt

    Hi, hoping to get some advice

    I've had Guide RS brakes on my bike for about a year, and in the last few months the levers have gotten a bit slow to return.

    Basically when I squeeze them, the lever doesn't spring back very quickly. Doesn't seem to impact the operation as they grab hard and there is no indication the pad is rubbing on the disc due to the slow return.

    They brakes are a bit spongey, so i will be bleeding them in the next couple weeks, but after some reading it doesn't sound like that will fix it.

    There have been a few posts around where people had something similar and SRAM fixed it under warranty, but I don't have this option as I bought them 2nd hand.

    I wash the bike after every wash and usually re-lub everything with JL69. So not sure if I should not be doing this, etc.

    Anyone else has similar issues/solutions?
     
  2. slimjim1

    slimjim1 Likes Dirt

    Sticky pistons?
     
  3. Jesterarts

    Jesterarts Likes Dirt

    Yeah. That's what it's looking like.

    Update since my post; I now have new internals coming... lol.

    So looks like later this month I will be doing some work on my brakes.
     
  4. Nambra

    Nambra Likes Dirt

    Can you confirm what the new internals are - is it the piston assembly in the master cylinder? Did SRAM come to the party or did you have to buy them yourself?

    I've got a similar symptom on my front Guide brake, and they have been bled recently - no effect on performance but the lever just isn't snappy in return.
     
  5. Jesterarts

    Jesterarts Likes Dirt

    So the internals kit is this:
    http://www.ebay.com.au/itm/322255340303?_trksid=p2060353.m2749.l2649&ssPageName=STRK:MEBIDX:IT

    They do not sell the piston by itself. I did find a video that basically walked you through the process of sanding the piston lightly as it seems to be the piston plastic rather than the o-rings that cause the issue.

    The key thing is to ensure you get the right kit for you variant, as R, RS and RSC all have different internals, but most importantly the piston is different.

    Didn't bother contacting SRAM as I can't see why they would come to the party from a warranty standpoint. The kit isn't that expensive and I see it as an opportunity to learn a bit more about bike servicing. :)

    Once everything comes in I will post up results. Depending how motivated I am feeling, might even go as far as a video of the process.
     
  6. Dozer

    Dozer Heavy machinery. Staff Member

    Can you link me to that video please? Keen to know the drill. ;)
     
  7. jarrod839

    jarrod839 Banned

    I had the same issue about 2 months ago and i had a bleed carried out and it fixed it for about a few runs then it returned but not as bad. You can fix it by just pumping the lever and it comes good for a bit then returns.

    Here's the bad news the guide rs and rsc levers suffer from the 12 month syndrome basically the piston flogs out and allows air to get into the line and trapping oil behind the piston so as why they don't return.

    Ive had mine for 12 months aswell and the only solution is upgrade to the sram ultimate lever as they rectified the issue in the ultimate lever.
    Don't waste time or money on the internal replacement it will only be more trouble than what its worth.
     
  8. Jesterarts

    Jesterarts Likes Dirt

    https://www.youtube.com/watch?v=pGfUXiMsl1s

    This guy does it on the "R" brakes but the process to take everything apart looks the same.

    He didn't actually show the sanding, but highlights the bits that need attention and the result he gets seems pretty good.

    A bit more on the issue and fix:
    http://www.pinkbike.com/forum/listcomments/?threadid=189827

    Anyway. Once I get everything apart I will see what is what i guess.

    Hmm... that sucks. But is it the piston or the o-rings? As my understanding is that the key issue is that contaminants get in and prevent a smooth action of the piston which doesn't itself hold back oil. Thus why giving it a sand seems to help.

    Anyway. I'll make sure when I take things apart I take pictures, etc to try and work out what is going on.
     
  9. JoelFitz

    JoelFitz Likes Dirt

    There is a big thread about this on MTB Forums. A lot of people are finding that they need to take a bit of material off the piston in the lever. Or there is now a kit with a revised piston? Worth checking out anyway.
    Mine did the same thing. SRAM warranted it. But now a year later it's happened again and out of warranty.
     
  10. Jesterarts

    Jesterarts Likes Dirt

    Sounds like they just replaced it with the same part and didn't actually resolve the issue.

    Well, I will have 2 spare pistons once my kit arrives so if it starts again in 12months... I have a set to muck around with.
     
  11. link1896

    link1896 Eats Squid

    My left lever (Guide R) is starting to exhibit the laziness, and I've just acquired a second set of brakes that also seem to have suffered this fate, so I will get them apart soon and will take a close look at the lever piston's dimensions. Thinking I might make some new lever pistons out of aluminium.

    Comparing Guide R to Guide RS in the 2016 SRAM spare parts catalog, the plastic piston assemblies are identical, but have different part numbers due to associated parts with different linkages from the lever.
     
  12. Jesterarts

    Jesterarts Likes Dirt

    Interesting. Maybe they changed the design. I am km my phone so can't do links, but there are a few pages where people have pulled apart their RS levers. Their piston's have a big, wide cylindrical part on the non-spring end.
    But the kits you can buy now don't have it. Maybe that was the problem in the design and the new kits have it resolved?
     
  13. link1896

    link1896 Eats Squid

    The part number is 11.5018.005.00, a google image search reveals there has been a redesign, part number hasn't changed but I see both variants. One with a lot of thickness behind the seal, the other had minimal thickness, just around the seals.
     
  14. rone

    rone Eats Squid

    It's the ghost of Avid.
     
  15. JoelFitz

    JoelFitz Likes Dirt

    I'm trying to decide if I send mine back under warranty again or bite the bullet and get some hope e4 brakes? Really dislike being without bike while waiting on warranty.

    Sent from my XT1092 using Tapatalk
     
  16. JTmofo

    JTmofo XC Enthusiast

    E4's will change your life............
     
  17. JoelFitz

    JoelFitz Likes Dirt

    Have the ultimate's fixed this problem or as level internals are the same it'll just happen to them too?
    Big outlay for the E4's, but Merlin have them for $360 at the moment.. Otherwise keep warranting the guides I guess. Seems no permanent fix though is there? - going to keep screwing up?
     
  18. link1896

    link1896 Eats Squid

    Quick disassembly this morning.

    I have v1, very stuck pistons. Took a lot of force with a small Allen key to move the piston out of the lever.

    I can see how to vacuum bleed :)

    Image1474497443.190957.jpg
     
  19. JTmofo

    JTmofo XC Enthusiast

    Ultimates will be more expensive than E4's? Surely?
     
  20. JoelFitz

    JoelFitz Likes Dirt

    Yeah true, the E4's actually pretty good priced.. Some say lacking power compared to the others?
     

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