Tech Tuesday - Shimano Brake Pad Replacement

Nov 16, 2010 at 0:09
Nov 16, 2010
by Mike Levy  
 
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Any rider who hits the trails on a regular basis will have had to replace their brake pads at some point - the more you ride, the faster they wear out! If you haven't done the job yet, you're in luck. Today's Tech Tuesday takes a closer look at replacing the pads in a Shimano brake system.

Inside you'll find some pointers to make the job easier, as well as a video guiding you through the process.



Along with your drivetrain and tires, your bike's brake pads are considered to be a consumable item. That is, they wear out while doing their job and require replacement over time. If allowed to wear too thin or even completely out, you will not only end up with a bigger repair bill that could also include rotors, but you're also putting yourself in danger. Some riders put off replacing their brake pads so long that they end up using the backing plate as pad material, and once that happens it can take only a few minutes of use to completely destroy a rotor. I've personally witnessed rotors being worn so thin from this that they fail catastrophically, folding in half in the blink of an eye and instantly pitching the rider. Scared yet? Long story short, inspect your brake pads often and replace when necessary for better performance, to save yourself money in the long run, and to prevent injury. Keep reading to get the lowdown on how to do this repair job.

You'll need to remove the reservoir cover when installing the new pads, but you shouldn't have to perform a full bleed. Have a rag handy to catch any drips that happen while you work on your bike and be sure to not get any fluid on the new pads or rotor.
You'll need to remove the reservoir cover when installing the new pads, but you shouldn't have to perform a full bleed. Have a rag handy to catch any drips that happen while you work on your bike and be sure to not get any fluid on the new pads or rotor.


Some pointers before you begin...

• As mentioned above, don't do anything half-assed when working on your brakes. Take your time and do it right, and if you don't feel up to it, get your local shop to do the job for you.
• It is always recommended that you have a clean work area when doing any brake work. Accidentally putting your new pads face down onto a dirty counter can ruin them. Save yourself time and money by doing a quick clean of your bench before you start.
• Never ever use anything metal, such as a screwdriver or hex key, to push the pistons back into the caliper. Doing so can damage the pistons by scratching the sealing surface and you will have to replace them.
• Use a rag and some isopropyl alcohol to clean the caliper before, and especially after, you replace the pads. This will greatly lessen the chance of you contaminating the new pads.
• Once you have the threaded pin and snap ring removed, put them somewhere safe where they won't get knocked off the counter. A magnetic bowl may seem a bit extravagant, but it is perfect for keep small bits like these from going missing.
• Anytime I'm dealing with brake fluid, be it mineral oil as found in Shimano brakes or DOT fluid as some others use, I'm careful to keep it from getting on anything that it shouldn't be on. To that end I will be sure to put a clean rag over the rotor and caliper that I'm not working on, something that is especially important on a system that may overflow at the master cylinder when changing pads. It is also good practice to put the removed wheel in a safe spot, not leaned up on the repair stand under your bike...
• Some people like to leave the old pads in place while pushing the pistons back as it protects the pistons from damage. This is certainly an option, but there is a good chance that this will render those old pads completely useless. Why does that matter? I like to keep my old pads for spares just in case I'm on the road and find myself needing to use them.
• Inspect the old pads for signs of uneven wear. Pads that are worn on an angle are a sure sign of a misaligned caliper.


Looking for a bit of help? Check out the technical documents on Shimano's website for more information.


When do you replace your pads? Shimano recommends not letting the pad's braking material wear thinner than 0.9 mm, but it certainly doesn't hurt to replace them sooner than that. My personal rule is to not let the pads get any thinner than the thickness than a dime. You'll also know that they have worn much too thin once the silver pad spring starts making contact with the rotor. If that is happening you know that you should have replaced the pads awhile back!


You'll need a plastic tire lever, some hex keys, a small phillips screwdriver, a clean rag, and the red Shimano pad spacer.
You'll need a plastic tire lever, some hex keys, a small phillips screwdriver, a clean rag, and the red Shimano pad spacer.


What's needed: 3 mm hex key, plastic tire lever, small phillips screwdriver, clean rag, isopropyl alcohol, the red Shimano pad spacer, and of course your new pads as well.



Watch the video to see how to change the pads on your Shimano brakes:

Views: 40,470    Faves: 111    Comments: 12



While your bike's brakes can be intimidating to work on, reading the instructions and having the right tools will make the job easy. If you have any pointers that you'd like to share, put them down below!



Past Tech Tuesdays:

Technical Tuesday #1 - How to change a tube.
Technical Tuesday #2 - How to set up your SRAM rear derailleur
Technical Tuesday #3 - How to remove and install pedals
Technical Tuesday #4 - How To Bleed Your Avid Elixir Brakes
Technical Tuesday #5 - How To Check And Adjust Your Headset
Technical Tuesday #6 - How To Fix A Broken Chain
Technical Tuesday #7 - Tubeless Conversion
Technical Tuesday #8 - Chain Wear
Technical Tuesday #9 - SRAM Shift Cable Replacement
Technical Tuesday #10 - Removing And Installing a Headset
Technical Tuesday #11 - Chain Lube Explained
Technical Tuesday #12 - RockShox Totem and Lyric Mission Control Damper Mod
Technical Tuesday #13 - Shimano XT Crank and Bottom Bracket Installation
Technical Tuesday #14 - Straightening Your Derailleur Hanger
Technical Tuesday #15 - Setting Up Your Front Derailleur
Technical Tuesday #16 - Setting Up Your Cockpit
Technical Tuesday #17 - Suspension Basics
Technical Tuesday #18 - Adjusting The Fox DHX 5.0
Technical Tuesday # 19 - Adjusting The RockShox BoXXer World Cup
Technical Tuesday #20 - Servicing Your Fox Float Shock
Tech Tuesday #21 - Wheel Truing Basics

Visit Parktool.com to see their entire lineup of tools and lubes.
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50 Comments

  • + 6
 Here's an extra pro-tip that will help anyone using Shimano brakes: when replacing your pads, take a small amount of Shimano brake fluid and put it on the pistons before pushing them back into the caliper. This will help lubricate them and allow them to move more freely, avoiding what I call "SPS" or "Sticky Piston Syndrome." SPS is common in almost every Shimano hydraulic brake system. Just make sure you clean all of the brake fluid off the piston area before you install the new pads, or else you risk contamination.
  • + 3
 Great tech tuesday! I didn't know changing my brake pads required me to do all this, I certainly didn't when I changed my pads last time. Thanks! Btw, you have a really funny laughter. Big Grin
  • + 11
 Theres that funny face again!hahahahahah...
  • + 2
 or retarded laughter, whatever...
  • + 0
 Don't get bits on your bike kids... ESPECIALLY, and I cannot stress this enough, bits of ANYTHING!
  • + 1
 facial expression again haha! love it.
  • + 1
 Shit do a video on how to bleed them, my rear has got shit loads of air in it!
  • + 1
 Im pretty sure they already made a vid about bleeding
  • + 1
 Nah, just on Avid brakes. It's a different process for these brakes, but also alot easier when you first have done it once.
  • + 3
 This facial expression is a lot better than some in the past!
  • + 3
 "what is a bit of anything?"
"...oreo cookies" lol
  • + 2
 This was a great one today guys! I had no idea that you had to be so careful with the pads or with not using metal while pushing in the pistons. But if you did know, one would not know about these things. Please, please, Please have a Shimano bleeding process as your next one as I'm going to make that my winter project. Thanks Pink Bike
  • + 5
 A 5 min winter project? Razz
  • + 3
 Its still a project.
  • + 3
 sorry if this is an obvious question, but what is the purpose for removing the reservoir cover? I've changed the pads on both Shimano and Avid brakes many times and never had to do this.
  • + 1
 then you have to wait... most brakes these days don't get air to the system easily as long as someone "closed" it properly. The best chance to pick up some air to the system is a trip to a bikepark including a flight (temperature/ air pressure difference), then few days of heavy duty braking then flight back, and in-garage gearing adjustment few days after coming back home or anything that takes to flip the bike up so the built up bubbles make their way to the calipers - done! Smile


And well bleeding is a part of everyones life...
  • + 3
 i might be overlooking something critical here, but if it's a closed system, how would temperature/air pressure differences cause air to breach the seals? i'm assuming there is no air in the brake in the first place.
  • + 1
 well that was a pure assumption taken from own experience. a bit stupid maybe... but I thought that somehow the system must have sucked the air in.
  • + 2
 It is an open system
  • + 7
 the reason for opening the reservoir cover is because when the pads wear it also pushed the pistons out so that the brakes feel consistant no matter how much brake pads have been used. When the pistons are moved further out it creates a 'suction' in the reservoir creating a large enough vacuum to pull in unwanted air. Then when you push the pistons back out it pushes the brake fluid to the reservoir. Opening the reservoir cover allows the air to escape. Hope that helps.
  • + 1
 I haven't had to remove the reservoir cover on Shimano brakes either, but have definitely had to take out the bleed screws on a few Avids and Hayes brakes. I probably would skip that step unless the pistons don't press back easily.
  • + 1
 @Carlos - bare in mind the design of moutain bikes is to be as light as possible (no massive oil reservoirs), to be as cheap as possible to manufacture and as durible as possible (no delicate reservoir covers).
  • + 1
 I know the Shimano tech docs say to pop the cover off, but I can't say I've ever needed to do it. I'm pretty lazy and a bit of a hack, but still... Pull the pin, pull the old pads, clean, lube and cycle the pistons, push the pistons back, slide in the new pads and spring, put the pin back in and away you go. Justsayinknowwhatimsayin?
  • + 1
 i have a problem with my pads (or rotor), so i cleaned my disk brake with a degreaser but now my brakes stop like sh*t!, so i sanded the pads abit ant cleaned the pads and rotor with alcohol but after braking alot it still isent good as befor... how can i fix it?

and any tips on how to true the a rotor? it is just a lil bent nothing to much.

thanks Smile
  • + 2
 you should have/and still can use a brake cleaner, its specially meant for brakes, degreasers sometimes leave a film on the pads and rotor. and to true your rotor you can just bend it slightly by hand while its still on the wheel, its not the most high-tech way to do it but it works.
  • + 1
 i know the vid is for shimano but when i replace my avid pads all i do is get one syringe from the bleed kit, put it on the caliper and push back the pistons as needed and install new pads. that way you can just push some brake fluid back in to however close you like your pads and not lose your bleed.
  • + 2
 oh... have to try that with my XTs! I was just about to get into the bastard in coming days. Otherwise if SPS got too bad is it necessary to take the caliper apart and clean the pistons inside?
  • + 3
 Most Shimano calipers are one-piece units, so there's really nothing you can take apart, per se. However if you want to pop the pistons out and clean them, you can unhook your caliper, stick a compressor nozzle in where the hose would go, and blow the pistons out. Just be sure to pad the caliper heavily with a rag or towel so that brake fluid doesn't shoot everywhere when you use the compressor.
  • + 1
 ok! sounds good!
  • + 1
 Using latex gloves (that don't degrade) when doing brake work can help with contamination and keep fluid away from your skin, which is more important with DOT-based systems but still good practice with mineral-based brakes.
  • + 1
 Nice i was wondering how to do it...thanks.....

I have a question if the fluid is kind of black it means that it is time to replace the fluid???......do i have to do a full bleed???
  • + 2
 Wow! You definitely have to replace the fluid. You have to drain the whole system as much as possible, then bleed it. I would also rinse the system with brake fluid a couple of times after draining and before you start the bleeding.
  • + 1
 thanks..i will...as soon as posible
  • + 3
 Tech Tuesday is awesome. I always watch. My request is for a TT on height adjustable seat post servicing. Thanks
  • + 1
 That would be totally useless for 98% of the riders here on the forum.
  • + 1
 Staike- The same could have been said for how to fix a broken chain but theres still a TT on how to fix a broken chain, and lets not forget how to change a tube.... True many riders knowledge is far past others here on PB but lets not forget about the noobies who dont know these things.
  • + 3
 Most of the riders here actually have chains and tubes. Very few have a height adjustable seatpost.
  • + 1
 Thats a fair statement. But if you think about it, how many people are gonna have a Boxxer WC (Yes I know a lot of people do but I'm saying most people prolly dont) or Elixir brakes. I havnt seen one person while out riding the little bit of DH in my area with either of these parts. Any tips from people that know what they are doing such as PB are usefull when trying to set up any bike.
  • + 5
 How false is staike's statement 4 years on. It's 2014 and seems every motherfucker has a dropper post!
  • + 2
 I'm requesting an overview of necessary after-ride maintenance, or what to do before you store your bike for the winter.
  • + 8
 Here's what you do before you store your bike for the winter: you don't. Ride it!
  • + 1
 thats always my plan but last year there was too much snow and when there wasnt snow the trails were frozen solid......so what should i have done before i left the bike over the winter. Razz
  • + 1
 Wash it, lube the chain, gear down so the wires won't stretch and then store the bike somewhere inside your house. Beer
  • + 2
 aha - so that's why Sharon's brakes weren't working. I guess the backing material on brake pads isn't so good for braking
  • + 2
 only use a plastic tyre leaver to push back the pistons..........oh dear. Frown
  • + 3
 I wouldn't worry too much about that. I've always used a 10mm wrench. Might be hard to push evenly with most tire levers.
  • + 1
 or just do as he say and use something plastic, so you don't have to spend time and money on new pistons. use a plastic spoon or whatever, something stiff and with a big contact flat would do the job just perfect.
  • + 1
 wat kind of bars were those
  • + 0
 I never thought I'd see a how-to on installing brake pads...
  • + 0
 wait............ canada uses dimes?

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