Clear advice, nice one. My GRX brakes would not stop rubbing using all of the above techniques... I had to bleed the brakes to get the pistons to retract properly. I also find that flat mount bolts need to be tightened a tiny bit at time as going all-the-way tight one one and then the other can mis-align your carefully straightened calliper. So annoying!
Exactly this. Spend ages aligning the calliper only for it to become misaligned by tightening the mounting bolts back up to the correct torque setting.
Really clearly explained! Thank you! Just getting used to servicing my disc brakes. I solved a ticking rotor with a gentle bend using the tool. In future, I’ll keep these other possibilities in mind and follow these procedures as needed.
This is a wonderfully clear description of basic disc brake maintenance. I've tried the first method -loosen brake caliper bolts, apply brakes, and then tighten the bolts- and it works almost every time. Thanks for the tip about the tool, this seems like a must-have. (I've actually damaged pistons using screwdrivers, etc.) I'm more skeptical about your guidance regarding disc rotors. In my experience, if you're having brake problems, it's pretty much never a rotor issue. If you're not throwing your bike into your car every weekend, your rotors will probably be largely intact for a good 5-6 years. If you do have a bent rotor, trying to bend it back will probably make it worse; I've actually watched a bike mechanic destroy my disc rotor right in front of me by bending the **** out of it. If my rotors ever get bent, which will almost certainly never happen, I'll just avoid a world of bother and just replace them.
I had disks rubbing for a year and I couldn't figure out the cause. I don't know why it never occurred to me to reposition the the whole brake by loosening the connecting bolts, apply brake, check center, and tighten. Thank you very much for reminding me of this. Solved a long-running frustration and makes riding just that much less aggravating. It's the simple things most of the time.
Great explanation - wish I'd found it before I started sorting out my new rotors. Way better than the other vids on the subject that came up in my Ytube search!
Excellent video! I can only add that if you are resetting the calliper pistons by pushing them in when they are used (to fix rub or replace pads) then you can take the pads out and clean the sides of the protruding piston so it does not drag (brake dust) gunk back into the calliper. Also check the width of the rotor as part of the (truing) work - wearing thin can make it easier warp but also closer to end of life to replace
Very nice video! However I do use a few helpers along the way - I have an alignment tool which you put in between the pad and the rotor which makes adjusting the caliper a bit more reliable and instead of the proper tool I just use an adjustable monkey wrench to straighten out the disks. No issues there - I always managed to straighten out the disk pretty much completely. Another tip for aligning the rear caliper - take off the chain so that you don't have the freehub noise when you check for misalignment.
Two things - 1. dont worry too much if there is a bit of rub with a new break pad, they are precision engineered and you are on the limit of the range of movement until it wears slightly and stops rubbing. 2. My calipers were perfectly aligned but after 2 years, the wear for each pad is not parallel, and there is a bit of a squeek. The caliper can be misaligned by being slightly twisted it seems. I am going to try and align them with very thin feeler guages when I replace the pads and see if that works better.
Clear video and great job. I've used a alignment tool in the past for aligning the caliper with good results. Like a little shim for the rotor that inserts into the caliper. Was there a reason you didn't go that route? Some reason you shouldn't use?
Very comprehensive video, brilliant. Can you tell me the make of the rotor truing tool Jim used, as it seems more versatile than any other I have seen? Thanks
Maybe mtbers don’t care too much about their brakes dragging. But for road bike use, disc brakes need a redesign. Thicker rotors and more pad clearance.
Great video.................he's obviously in the UK but the bike is set up for LH Drive countries with the left hand operating the front brake..........why?
Good video. Surprised at the recommendation to use the ball end if the Allen key of the square end doesn't reach - shouldn't the advice be to get an appropriate tool? Especially after the emphasis on getting a disc brake tool, rather than getting by with pliers and tyre levers.
@@tombolo22 The ball end is usually viewed as inappropriate for high torque applications, because it runs a risk of stripping the head of the bolt. If there was no down side to ball ends, why would you ever have square ended tools?
@@tombolo22 I'd suggest that 5-8Nm is reasonably high torque for a 4mm hex bolt, I don't think they'd go much higher. In answer to your question, I never really "got" torx head bolts; in my experience of small torx bolts they have been more price to damage than hex bolts.
Before pushing the pistons back in, I would recommend actually removing the brake pads and cleaning the pistons as best as you can with alcohol. In my experience if you manually send the pistons back before attempting to clean them then the "sticky" piston problem only gets worse.
I‘m changing my wheelset from time to time, and often step 1 does not work. So I align it same as he does by looking down - but as soon as I thighten the bolts, it‘s not straight anymore… I also used different tools.
Trueing rotors is a drag... but more importantly: If you have one of the pistons not going back properly, even after cleaning them over and over, it might mean the seals have hardened. Means you need new calipers. I've once been fooling around with a brake for hours on end, because I didn't knew that those seals are made of some sort of rubber that becomes stiff after a few years.
Great vid Jim. Two other very important things to check for first: 1. The wheel is properly centred within the fork. Even a thru axle hub system can have some play. Before you torque up the thru axle place the bike on the floor, put some weight on it and then tighten up. If you do it on the stand the wheel might not 'settle' correctly. 2. The rotor has been seated properly on the hub. Sometimes they can be skewed - when they've be put back on over some grit.
I had to stop using disc brake cleaner on my rotors because it made them squeal like mad, same if the pads got cleaner on them too. They're quiet when they're dirty. Bit like the saying "squeaky clean"
