HYDRAULIC BREAKS ( REAR TIRE)

SAM K

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My EBIKE hydraulic breaks are not working since I removed my rear Flat tire. When I move my bike without any power, it works perfectly but when I put the power on and move my tires to test the break, it does not work. What can be the reason? I already bleed the breaks and then it start working but my break disk became very hot to touch. I tried to fix it and run it but after the break does not work. Disk is cool now but the break does not work.
Thanks
 
My EBIKE hydraulic breaks are not working since I removed my rear Flat tire. When I move my bike without any power, it works perfectly but when I put the power on and move my tires to test the break, it does not work. What can be the reason? I already bleed the breaks and then it start working but my break disk became very hot to touch. I tried to fix it and run it but after the break does not work. Disk is cool now but the break does not work.
Thanks
You probably glazed the disc brake pads & rotor up from getting it hot. You can sand the rotor & pads to de-glaze them. But I recommend you buy new disc brake pads & rotor & replace them.
 
You probably glazed the disc brake pads & rotor up from getting it hot. You can sand the rotor & pads to de-glaze them. But I recommend you buy new disc brake pads & rotor & replace them.
I just cleaned the disc with alcohol. Nothing else. How to de-glaze break pads & rotor?
 
Sandpaper or coarse steel wool

BTW, your rotor will normally get hot with use. That’s by design. Friction stops you, friction makes heat.
Touch quick hot is ok, burn off your fingerprints or glow in the dark is a problem.
This is why you don’t want to continuously ride your brakes on a long downhill.
 
As an aside to the above — every time you use your brakes you are scrubbing off (wasting) energy that came from the battery or your pedals to get you up to speed.
If you can learn to manage your speed by looking ahead so you can avoid using your brakes your battery range will be further.
 
I already bleed the breaks and then it start working but my break disk became very hot to touch.
This line says a lot in terms of what is wrong. You are having contact with the rotor and the pads are superheating the system from the constant drag. That will cause what is known as brake 'fade' which translated is "brakes do not work". If you leave something like this be without fixing it, you can wear the pads down or possibly even boil the fluid, which will cause air bubbles that you have to bleed out... every time you ride.

So it sounds like you have two problems. The first is the contact, and the second is the damage caused from the contact. Possibly ruined pads that were worn down. Possibly fluid with air bubbles. Maybe both.

Here's a test: Put the bike's back wheel up off the ground. Hit the throttle on that back wheel and then lift off the throttle. What happens to the wheel spinning? Does it spin along forever until it slowly stops, or does it stop almost immediately? I'll bet its the latter, and the only reason you didn't catch on to this is you are throttling an ebike whose motor can overpower a misaligned caliper and rotor that has this problem. Also you will be able to hear the brakes rubbing on the rotor.

Don't bother refinishing the rotors or doing anything besides making sure the rotor is centered between the pads and the wheel spins freely. If you let something like this happen without recognizing the issue, maybe its a good idea to take the bike to a shop. There's no shame in this. People are good at different things and bicycle mechanics is not necessarily one of them. But really this is a problem that should have been easily caught and very quickly fixed, so maybe its time to hand the problem off to someone more familiar with the equipment.
 
No, It does run freely and no noise. After cleaning with Alcohol, i guess the pads are glazed. I will try to de-glaze it and will see the result. Misalignment can be issue too. How to make a little wider gap between break pads so that disk should not rub with the pads?
Thanks
 
No, It does run freely and no noise. After cleaning with Alcohol, i guess the pads are glazed. I will try to de-glaze it and will see the result. Misalignment can be issue too. How to make a little wider gap between break pads so that disk should not rub with the pads?
Thanks
They make a tool for adjusting your disc brake pads air gap. I use 2 pieces of cereal box to set my disc brake pads to rotor air gap.
 
What does "the brakes do not work" mean? You squeeze the lever and it makes contact but the wheel doesn't slow down? You squeeze the lever and nothing happens? What exactly?

What do the pads look like? How much pad material is on them? What do the rotors look like? If you have run out of pad material, then they'd look pretty nasty. Is there fluid residue on the rotors? They would show some streaking if so. If you squeeze the brake lever and get down to the wheel when you do it, do you see the pads try and clamp the rotor? You should be able to see movement. Also the interior of the calipers will show fluid once you remove the pads if the pistons are leaking. Pictures showing the rotors, the pads (removed) etc. would help with diagnosis. Its too early to be thinking the pads are glazed. Brakes with glazed pads will still work. Just not as well as they should. You're saying the brakes do not work.
 
What does "the brakes do not work" mean? You squeeze the lever and it makes contact but the wheel doesn't slow down? You squeeze the lever and nothing happens? What exactly?

What do the pads look like? How much pad material is on them? What do the rotors look like? If you have run out of pad material, then they'd look pretty nasty. Is there fluid residue on the rotors? They would show some streaking if so. If you squeeze the brake lever and get down to the wheel when you do it, do you see the pads try and clamp the rotor? You should be able to see movement. Also the interior of the calipers will show fluid once you remove the pads if the pistons are leaking. Pictures showing the rotors, the pads (removed) etc. would help with diagnosis. Its too early to be thinking the pads are glazed. Brakes with glazed pads will still work. Just not as well as they should. You're saying the brakes do not work.
Yes, I squeeze the lever but nothing happens. Bike ( ENGWE) is almost new. Only 150 miles on it. Since I changed the Rear flat tire, break stop working. I just installed Anti torque rotation on the rear wheel. Now I am getting break problems. What should I do?
 
If you squeeze the lever and nothing happens (and its truly "nothing") then that implies there is no fluid in the brake hose, or the brake hose is physically not connected to the caliper. You'd also have your brake lever sink all the way down to the handlebar. It would be just like running out of fluid in a car in terms of lever behavior.

If on the other hand "nothing" means the pads do contact the rotor, but the contact is minimal enough to not produce a meaningful result, then the standard checks would be 1)bleeding the lines to remove air bubbles - and you say you already did that. 2) would be checking that there is sufficient pad material on the pads. 1mm to 2mm thickness is considered "time to change the pads" with new ones. 3) would be to get out your calipers and measure the thickness of the rotor to see if it is below spec. Items 2 and 3 are wear items unlikely to be the cause on a bike with only 150 miles on it.

You said you bled the lines already. What happens when you do it again? More bubbles? If so, then either you did a bad job of bleeding or there's a break in the line. But a break in the line (or a leaky piston in the caliper) would mean brake fluid would be leaking out and you should be able to see that pretty plainly.

Since you describe "nothing" as the result, that seems to rule out pad glazing, where you'd still know the pads are in contact and the brakes would be working... just not very well. Besides, glazing comes from extreme use and not removing and then reattaching a rear wheel.

Its troubling to hear you just put the anti-torque washers on the wheels. They never should have been removed and the bike never should have been operated without them, as the motor can spin out and destroy the frame, with no way to fix it.

I'm going to repeat that it seems there is enough uncertainty here about what is happening, and enough lack of clarity, that a local bike shop or just finding someone who knows how to work on bikes should be the next step. These things just aren't very complicated so the solution should be obvious to someone familiar with the job who can lay eyes/hands directly on the bike.
 
Piston is not moving at all. Probably air in the system? How to bleed from near the brake pads?
Thanks
 
Piston is not moving at all. Probably air in the system? How to bleed from near the brake pads?
Thanks
There are many step by step tutorials out there. I wrote this one and it works for more than just Magura brand brakes.


This is a full bleed. You could also do a shortcut version that tops off the system, but from the sound of it you need to do a full bleed like what is described above.
 
There are many step by step tutorials out there. I wrote this one and it works for more than just Magura brand brakes.


This is a full bleed. You could also do a shortcut version that tops off the system, but from the sound of it you need to do a full bleed like what is described above.
OK. THANKS
 
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