Forum home Mountain biking forum MTB workshop & tech

Shimano and their leaky brakes

firealno9firealno9 Posts: 7
edited 14 October in MTB workshop & tech
Hi, I work in a bike shop and recently I've been looking to get myself some new hydraulic brakes for my MTB as both of my old SLX M675 calipers developed leaks from the piston seals, and I've had Deores before them that also did this. Anyway, recently I've ordered 2 sets of the new SLX M7100s from our supplier Madison, a couple of months apart, and both times when I have received the brakes and taken the pads out of the caliper straight out of the box, the pads have oil on the back on them. What is going on with Shimano? I know this is a widespread issue but has anybody else seen this on brand new brakes before that haven't even been used yet?

I guess this post can also serve as a warning. If you buy new Shimano hydraulic brakes, check the backs of the pads before you fit them to your bike and start using them, because if my experience is anything to go by it seems like there's a good chance you will need to return them straight away.

Posts

  • gomezzgomezz Posts: 66
    Could it not be something like Copper Slip anti seize grease ?
    I put this on the back of my pads in my motor bike days.
  • firealno9firealno9 Posts: 7
    edited 14 October
    gomezz said:

    Could it not be something like Copper Slip anti seize grease ?
    I put this on the back of my pads in my motor bike days.

    No, because they don't put that on their pads. Also, the first set of these M7100's I got, I wiped the oil off the back as thought possibly it may have come from somewhere else and fitted them anyway. A day or 2 later and the pads had become contaminated and started squealing, so I took them out and the oil was there again.
  • reaperactualreaperactual Posts: 620
    edited 15 October
    Had lots of sets of Shimano brakes from entry level and up in the past, currently have SLX M7000's and although I had a sticky pistons issue recently after two years of use never had a problem with leaks at connections or piston seals on any set I've used. Same with most riders I know that use Shimano brakes including M675's.

    Could be a bad batch? Maybe quality isn't what it used to be on the M7100 and heard of a few leaky pistons on newer models but not when brand new, possibly teething troubles or poor factory assembly?

    Hear other brake brands that have various issues of their own such as Sram with lever piston jamming in cold weather etc.

    Still reckon Shimano brakes are the best in the price range overall, cheap to replace units, easy to work on/bleed and wouldn't buy any other brand when it comes to brakes.
  • mully79mully79 Posts: 89
    i wont be getting shimano brakes again.
    Next time i will buy some nice Hopes and just transfer them every time I change bikes.
    Thats the beauty of fully rebuildable brakes where the spares are easily available.
  • david37david37 Posts: 417
    firealno9 said:

    Hi, I work in a bike shop and recently I've been looking to get myself some new hydraulic brakes for my MTB as both of my old SLX M675 calipers developed leaks from the piston seals, and I've had Deores before them that also did this. Anyway, recently I've ordered 2 sets of the new SLX M7100s from our supplier Madison, a couple of months apart, and both times when I have received the brakes and taken the pads out of the caliper straight out of the box, the pads have oil on the back on them. What is going on with Shimano? I know this is a widespread issue but has anybody else seen this on brand new brakes before that haven't even been used yet?

    I guess this post can also serve as a warning. If you buy new Shimano hydraulic brakes, check the backs of the pads before you fit them to your bike and start using them, because if my experience is anything to go by it seems like there's a good chance you will need to return them straight away.

    I work as a mechanic too and to my mind the leaky callipers is a complete pia. Of course my view may be jaundiced by the fact that no one brings good brakes in and asks me to solve a squeal. :).
  • lesfirthlesfirth Posts: 1,086

    firealno9 said:

    Hi, I work in a bike shop and recently I've been looking to get myself some new hydraulic brakes for my MTB as both of my old SLX M675 calipers developed leaks from the piston seals, and I've had Deores before them that also did this. Anyway, recently I've ordered 2 sets of the new SLX M7100s from our supplier Madison, a couple of months apart, and both times when I have received the brakes and taken the pads out of the caliper straight out of the box, the pads have oil on the back on them. What is going on with Shimano? I know this is a widespread issue but has anybody else seen this on brand new brakes before that haven't even been used yet?

    I guess this post can also serve as a warning. If you buy new Shimano hydraulic brakes, check the backs of the pads before you fit them to your bike and start using them, because if my experience is anything to go by it seems like there's a good chance you will need to return them straight away.

    I do not think that Shimano fill new calipers with hydraulic fluid to test them before they ship them out of the factory. Certainly not to the extent that the fluid has leaked past the piston seals. Is that what you think has happened?
  • lesfirth said:


    firealno9 said:

    Hi, I work in a bike shop and recently I've been looking to get myself some new hydraulic brakes for my MTB as both of my old SLX M675 calipers developed leaks from the piston seals, and I've had Deores before them that also did this. Anyway, recently I've ordered 2 sets of the new SLX M7100s from our supplier Madison, a couple of months apart, and both times when I have received the brakes and taken the pads out of the caliper straight out of the box, the pads have oil on the back on them. What is going on with Shimano? I know this is a widespread issue but has anybody else seen this on brand new brakes before that haven't even been used yet?

    I guess this post can also serve as a warning. If you buy new Shimano hydraulic brakes, check the backs of the pads before you fit them to your bike and start using them, because if my experience is anything to go by it seems like there's a good chance you will need to return them straight away.

    I do not think that Shimano fill new calipers with hydraulic fluid to test them before they ship them out of the factory. Certainly not to the extent that the fluid has leaked past the piston seals. Is that what you think has happened?
    Shimano fill their pre-bled systems that have faulty seals with fluid in the factory. The 2 pairs of brakes I got were pre-bled J kit ones which are already filled with fluid, and both of them had already leaked oil onto the back of the pads from the piston seals before they'd even been used.
  • lesfirth said:


    firealno9 said:

    Hi, I work in a bike shop and recently I've been looking to get myself some new hydraulic brakes for my MTB as both of my old SLX M675 calipers developed leaks from the piston seals, and I've had Deores before them that also did this. Anyway, recently I've ordered 2 sets of the new SLX M7100s from our supplier Madison, a couple of months apart, and both times when I have received the brakes and taken the pads out of the caliper straight out of the box, the pads have oil on the back on them. What is going on with Shimano? I know this is a widespread issue but has anybody else seen this on brand new brakes before that haven't even been used yet?

    I guess this post can also serve as a warning. If you buy new Shimano hydraulic brakes, check the backs of the pads before you fit them to your bike and start using them, because if my experience is anything to go by it seems like there's a good chance you will need to return them straight away.

    I do not think that Shimano fill new calipers with hydraulic fluid to test them before they ship them out of the factory. Certainly not to the extent that the fluid has leaked past the piston seals. Is that what you think has happened?
    Shimano fill their faulty pre-bled brake systems with fluid in the factory. Both pairs I got were the pre-bled J kit brakes which means the system is already filled with fluid, and on both of them the oil had seeped through the piston seals onto the rear of the pads before they'd even been used, fresh out of the box.
  • On all 8 pads from both pairs of brakes, there was a ring of oil on the rear of the pads from where the edge of the piston contacts them.
Sign In or Register to comment.