rear break stopped working

[lilithharper 4]

little bit of back info was on a ride in the mountains going up was fine coming down well about half way down the rear break lost all pressure had to switch to using just the front break till i was off the mountain pulled over and after a few mins of just sitting the break seemed to start working again 

 

i have a nc700x dct 2014 if there just some like break kill switch that got triggered is it a heat thing like if it get to hot it kills the break the pads are allso a little tight since it started working again im just wondering why it stopped working in the first place 

[Tex 36,817]

It’s called brake fade. Much more common on drum brakes but it most certainly can happen with discs as well. I suspect you were ‘riding’ the back brake as you came down the mountain (maintaining a pressure on the pedal to keep your speed down) this will cause the symptoms you describe.

 

A far better approach is to select a lower gear and, keeping the throttle shut, that will slow your progress down the hills leaving the brakes free to be used when necessary.

 

When I had a DCT I would select ‘manual’ before steep downhills and then choose a low gear (second or third) for the descent.

 

It would be worth having the rear brake fluid changed and the pads examined and replaced if necessary.

 

 

Edited August 20, 2021 by Tex

[lilithharper 4]

8 minutes ago, Tex said:

It’s called brake fade. Much more common on drum brakes but it most certainly can happen with discs as well. I suspect you were ‘riding’ the back brake as you came down the mountain (maintaining a pressure on the pedal to keep your speed down) this will cause the symptoms you describe.

 

A far better approach is to select a lower gear and, keeping the throttle shut, that will slow your progress down the hills leaving the brakes free to be used when necessary.

 

When I had a DCT I would select ‘manual’ before steep downhills and then choose a low gear (second or third) for the descent.

 

It would be worth having the rear brake fluid changed and the pads examined and replaced if necessary.

 

 

i wasnt was just using the back break mostly for tighter terns but was mostly in 2nd or 3 gear and would come of the throttle before hitting the break the other times i was using the break was to make sure i was staying in lane when cars would pass 

[davebike 943]

Yes overheated brake Aka Brake fade 

Use more engine braking

Change brake fluid and I would expect pads 

I also on a DCT  I use manual and a low enough gear to get enough enging braking + try to slow   early enough that you use less brakes

 

I would definatly do a fluid change and check to pads  I burnt / dammaged pads getting the rear (OK not an NC ) over hot

[skorpion 946]

I would also upgrade to EBC HH pads in the rear BRAKE, less chance of fade, though could also be down to long overdue fluid change.

Edited August 21, 2021 by skorpion

[Andy m 23,707]

I would disagree on the definition of brake fad (disc and pad interface temperature hitting a point where expansion/heat has an effect on the lining interface ) but not the result. A modern disc will be cherry red and melting paint before it fades. This is fluid boiling off or air and the result is the same. The fluid needs changing now.

 

"Switching to the front brake" terrifies me. Lilith, are you by any chance American? Unless I misunderstood, you need some training. The front brake provides 51 to 100% of any controlled maximum deceleration and more than half of the available fluid cooling. You should be using it for every single moving brake application, it isn't a choice.

 

Andy

[MatBin 5,109]

I too was concerned about the "switching" comment, does sound like you were only using the rear brake, are we wrong?

Coming down the mountains and your signature (Lilith) points to American nationality and possibly over use of rear brake on a bike, Brits do have a tendency to assume most Americans practice this behaviour as from the web it does seem quite common and to us incorrect.

If you are using mainly the rear brake all the time then you need to revise your style and use more front brake. Of course there is also good advice that front brake on a loose downhill surface isn't good practice either, was this your situation?

Sorry if we have got this wrong.

In either case whatever definition you choose for brake fade, the result in your case was the same i.e. loss of brake due to overheating, fluid and pad change is now required.

Hope we have helped.

Edited August 21, 2021 by MatBin

[Andy m 23,707]

With functional ABS using the front brake does little harm on even a loose surface. If there is grip there is decel. If there is not there is ABS cycling (which is potentially off putting if not expected).

 

Andy

[Rev Ken 6,347]

1 hour ago, Andy m said:

I would disagree on the definition of brake fad (disc and pad interface temperature hitting a point where expansion/heat has an effect on the lining interface ) but not the result. A modern disc will be cherry red and melting paint before it fades. This is fluid boiling off or air and the result is the same. The fluid needs changing now.

 

"Switching to the front brake" terrifies me. Lilith, are you by any chance American? Unless I misunderstood, you need some training. The front brake provides 51 to 100% of any controlled maximum deceleration and more than half of the available fluid cooling. You should be using it for every single moving brake application, it isn't a choice.

 

Andy

As Andy says! The only time the rear brake should be used on its own is on extremely slippery surfaces or when slow riding about walking pace. I wonder if your 2014 bike has had a brake fluid change as after a while it deteriorates and its boiling point drops - hence your problem!

[lilithharper 4]

8 hours ago, Andy m said:

I would disagree on the definition of brake fad (disc and pad interface temperature hitting a point where expansion/heat has an effect on the lining interface ) but not the result. A modern disc will be cherry red and melting paint before it fades. This is fluid boiling off or air and the result is the same. The fluid needs changing now.

 

"Switching to the front brake" terrifies me. Lilith, are you by any chance American? Unless I misunderstood, you need some training. The front brake provides 51 to 100% of any controlled maximum deceleration and more than half of the available fluid cooling. You should be using it for every single moving brake application, it isn't a choice.

 

Andy

when i said i had to switch to using the front break i meant having to only use the front cuz where i was riding at the time is all terns hence why i was at low gearing and using the rear a good amount 

[lilithharper 4]

8 hours ago, MatBin said:

I too was concerned about the "switching" comment, does sound like you were only using the rear brake, are we wrong?

Coming down the mountains and your signature (Lilith) points to American nationality and possibly over use of rear brake on a bike, Brits do have a tendency to assume most Americans practice this behaviour as from the web it does seem quite common and to us incorrect.

If you are using mainly the rear brake all the time then you need to revise your style and use more front brake. Of course there is also good advice that front brake on a loose downhill surface isn't good practice either, was this your situation?

Sorry if we have got this wrong.

In either case whatever definition you choose for brake fade, the result in your case was the same i.e. loss of brake due to overheating, fluid and pad change is now required.

Hope we have helped.

ya the roads i was on at the time was very down hill and all corners where using allot of front break would not have bin great and lighter taps to the rear with very little front and lower gearing works the best if i was one straighter roads yes i always use both breaks in a controlled way and hope it doesnt have to be said but i will anyways letting off the throttle while breaking 

[lilithharper 4]

7 hours ago, Rev Ken said:

As Andy says! The only time the rear brake should be used on its own is on extremely slippery surfaces or when slow riding about walking pace. I wonder if your 2014 bike has had a brake fluid change as after a while it deteriorates and its boiling point drops - hence your problem!

had done the fluid a few months ago maybe 3 or 4 with bleed and everything but ya i could have just over heated it idk had never happened before in close to a year of having the bike