I had poor performance from my SRAM Apex hydraulic disk brakes. This weekend, I bled them, and it seemed to solve the problem. However, on my next ride, I decided to test the newly bled brakes with a particularly hard stop. When I did so, I saw a puff of smoke. I assumed that it was oil on the hot rotor, so I looked closer. Sure enough, when I pump the front brake hard, a little oil runs down the disc. Also, the lever is almost as soft as before I bled the brakes. At least the rear brake seems fine.

At this point, I'm not sure what to do. I know the disc needs to be cleaned and the pads need to be replaced, but I do not know how to fix the leak. I don't even know where the leak is coming from, because the bleed port and cable are dry on the outside.

A couple of questions: First, where could it be leaking from? Could it be from around the pistons? If so, how would you fix it? Second, could this be fixed under warranty? I assume it would be SRAM warranty, not Planet X, right? The bike is almost brand new. If so, how would I go about that? Do I take it to my LBS? The bike was bought online. Please help.

I miss the cheap and simple mechanical discs from my last bike.

  • 1
    You mention oil coming out of your caliper. Was this a minor inaccuracy in writing? Sram road hydraulic brakes typically use DOT5.1 fluid rather than oil. Be careful there since DOT 5 (sans the .1), which silicone oil, is not compatible with DOT 5.1 fluid.
    – gschenk
    Sep 4, 2017 at 15:49

1 Answer 1


Sounds like a bad piston seal to me. Could also be any seal from around the calliper area, split line, cracked calliper.

Assuming these are newish and you've not bashed them up this should be a warranty claim. This will almost always have to go through the place you bought the bike, but there are exceptions.

You should email SRAM, the maker, and the shop to see who wants it back and see if the whole bike needs to be retuned or just the failed brake.

  • Thanks. It's not the answer I was hoping to hear, because I do not look forward to removing the brake or to shipping the whole bike overseas back to the seller. I'll have to ask the seller if this could be repaired under warranty through a local bike shop.
    – gman
    Sep 19, 2016 at 3:37
  • 2
    @gman Consider supporting your local bike shops in the future - yes things are cheaper on line, but this is where the savings erode. Also ask your authorised LBS if they will do a warranty repair - its worth a go, LBS charges the repair back to the distributor or whoever.
    – Criggie
    Sep 19, 2016 at 4:42
  • It's free to ask, some companies are super helpful in this regard, some are terrible.
    – alex
    Sep 19, 2016 at 5:07
  • @gman, where are you and where'd you buy? I have a lot of problems like this as I move around loads. I tend to buy my bikes in bits and that helps.
    – alex
    Sep 19, 2016 at 5:13
  • 2
    Also, double check the bleed port screw. Sep 19, 2016 at 8:21

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