Rick Sanchez Posted August 16, 2015 Posted August 16, 2015 Hi Recently had my rear brake refitted and needed a new olive and banjo etc, and afterwards the brakes had ZERO stopping power and squeal very loudly. This is just the rear brake and the front brake still functions perfectly. I had no issues whatsoever with the brake before and I asked the mechanic about this and he said new resin pads would stop the squealing, as he said the current metallic pads look glazed over. Does anyone have any ideas? Will the new pads work and fix the braking power issue? Don't want to buy new pads if it won't necessarily fix the issue. Brakes are Shimano Deore M615.
Onegear Posted August 16, 2015 Posted August 16, 2015 Hi, before you buy new pads, maybe try the following: 1)Sand Rotor With about 800 grit. Sand pads also with about 800grit untill you have just removed a bit of the top layer of pads. 2)When you done that hold the pads over an open flame for a few seconds to dry decontaminate them. 3) Sand pads lightly again 4)Clean it all up with some thinners or I use sunlight liquid and water and then rinse again in wanter and let it all fully dry. 5) refitt everything, allign the caliper. 6)Find a long a hill, and brake HARD every few seconds to wear the brake pads in. It worked for me so I guess there is no harm in trying this before you spend money on a new set of pads.
Onegear Posted August 16, 2015 Posted August 16, 2015 And thats only if you sure the brake does not need to be bled.
Fisan Posted August 16, 2015 Posted August 16, 2015 6)Find a long a hill, and brake HARD every few seconds to wear the brake pads in. Haha hopefully you'll have some stopping power by this step...
Onegear Posted August 16, 2015 Posted August 16, 2015 Haha hopefully you'll have some stopping power by this step...He has the Front for backup haha
Rick Sanchez Posted August 16, 2015 Author Posted August 16, 2015 The mechanic cleaned everything with some kind of degreaser specifically used to clean mineral oil from the rotors and pads, so I don't think the pads are contaminated? But I will try sanding the rotor and pads.Otherwise I might put the bike on a treadmill to simulate a long downhill
Rick Sanchez Posted August 16, 2015 Author Posted August 16, 2015 I actually switched out the front and rear pads and the rear brake still did not work properly, but the squealing was gone. but the front brake then started squealing, despite functioning properly.
Rick Sanchez Posted August 16, 2015 Author Posted August 16, 2015 And thats only if you sure the brake does not need to be bled.Brake was bled and holds pressure. Lever also feels very firm, same as front brake
Onegear Posted August 16, 2015 Posted August 16, 2015 I actually switched out the front and rear pads and the rear brake still did not work properly, but the squealing was gone. but the front brake then started squealing, despite functioning properly.Then it definately means your rear pads were contaminated if it caused your front brakes to squeel too. Im not too sure though what would stop your rear brake from litteraly not working if it was bled at the shop. If you spin the wheel in mid air and press the back brake lever, will the wheel stop ?
Rick Sanchez Posted August 16, 2015 Author Posted August 16, 2015 Then it definately means your rear pads were contaminated if it caused your front brakes to squeel too. Im not too sure though what would stop your rear brake from litteraly not working if it was bled at the shop. If you spin the wheel in mid air and press the back brake lever, will the wheel stop ?Yes the wheel stops, but when riding, i can feel the pads touching the rotor when pulling the lever, but it has minimal braking power. I actually took the bike back because I saw it was leaking some fluid from where the hose meets the lever and the guy re-bled the brake, but I assume the pads are contaminated from the leaking fluid or from the first bleeding process. Will new pads fix this though? Or is the rotor also contaminated? In which case I assume your above mentioned method should sort it out?
Onegear Posted August 16, 2015 Posted August 16, 2015 The rotor can be contaminated but that literally needs cleaning with soapy water and then it's all sorted. So I do think you should try what I mentioned first. I'll send you a PM with some stuff which could maybe help.
Rick Sanchez Posted August 16, 2015 Author Posted August 16, 2015 The rotor can be contaminated but that literally needs cleaning with soapy water and then it's all sorted. So I do think you should try what I mentioned first. I'll send you a PM with some stuff which could maybe help.Thanks
Boerklong Posted August 17, 2015 Posted August 17, 2015 Put pads in frying on pan stove. It will smoke till its clean. Also think there is a leak of some sort.
BenReaper Posted August 17, 2015 Posted August 17, 2015 As already mentioned you can sand and clean the pads and rotor to make sure they are good(unless pads are contaminated).When the pads are fitted again loosen the two bolts on the mounting bracket of the brake caliper, pull the brake lever in and tighten up the caliper mounting bolts.I have had a similar problem before where the one pad had worn more than the other and it gave the effect of the caliper being off centre.Dont know if this is the correct way to do it,but this is how I did it and it worked for me.I do however believe that the bike shop should have fixed this for you,after all...that is what you paid for?
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