Idling in Neutral while coasting...then...no rear brake

RollieFree

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Oct 5, 2016
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Was slowly idling down a grade yesterday in neutral (coasting) and when I went for a little rear brake, there was none. So, yes I was moving. Yes I was in neutral. Yes the engine was running at idle.

After a pump or two, they came back like a failing master cylinder will act but the next time, again zero pedal. However, once I put it in gear and returned to regular operation, the bakes came back in full, normal operation and remained that way the rest of the day.

Anybody know what caused that?

Thanks,
RF
 

Squibb

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I believe you have a Gen1 2012 bike, flashed by Anthony, but I'm not sure of the mileage, back story or service history.

With the engine idling in neutral when coasting on a downgrade, I would have expected full brake function to be retained.

Personally I would question the linked ABS system & the rear brake master & slave, but ..........

- Are any codes showing?
- When was the brake fluid last changed & the ABS pump/module bled?
- Does ABS actually work normally in an emergency stop situation?

I seem to remember a lengthy thread on this subject, probably a couple of year back now, so it may be worth a quick search.
 

gunslinger_006

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My understanding is that short of the abs controller malfunctioning, there is nothing on or in the bike that could cause that, other than your rear master cylinder failing.

Even fully powered off, the brakes should and must work. The implications of losing brakes while in motion are too dire to allow a brake system to be beholden to the engine functioning normally.
 

14kmtnman

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At least we don't have the electric/servo powered abs brakes like what BMW had in the early 2000's that totally disengaged going over seams or bumps in the road. Talk about pucker power.... I know my 2013 brakes work without the engine running in or out of gear.
 

RollieFree

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Agree across the board. Brakes work fine engine off. Work fine in fear and under power. Work fine coasting with clutch in while in gear. In neutral....different story.
RF
 

Kyle_E

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Don't think it is this, but something I would look at first....

What's the fluid level in the reservoir?
 

Squibb

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Here we go. As ever, search is your friend ................. https://www.yamahasupertenere.com/index.php?threads/losing-rear-brake-after-a-good-bleed.25103/

Once you have checked this out, could I persuade you to look at the 3 questions I posed in #3 above. It would be nice to find it is the rear master, but past findings relating to a disappearing pedal point us towards the ABS module & the pump in particular. In your case, the conditions are strange, but the fact remains that your bike is unsafe to ride currently, so this needs to be tied down.
 

RollieFree

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I did search and read that yesterday and again this morning. I will bleed and cycle the pump, etc., as soon as I have the time. I will say that since that single conditional event, I have had zero sign of it. Checked this morning even engine off coasting and full brakes. I cannot repeat the condition. It really seems as if it got electronically confused somehow by the fact that I was in neutral, engine at idle and coasting for such a long time at slow speed. I am going to visit the service shop at the local dealer and see what they have to say after I do the bleed / cycle process. I know anything is possible and it happened for a reason, however I also feel that if it were a pump issue, or any other mechanical issue, once broken, it wouldn't suddenly repair itself and become flawless. especially with brakes. I'll get to the bottom of it and post up when I do.
RF
 

Skytower

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At least we don't have the electric/servo powered abs brakes like what BMW had in the early 2000's that totally disengaged going over seams or bumps in the road. Talk about pucker power.... I know my 2013 brakes work without the engine running in or out of gear.
Sold my 03 K1200RS and got the S10. It had the servo system, but the brakes still worked with the engine off. Operated like a car with power brakes. Had to use more effort than usual to stop.

As to the rear brake issue... If the relief valve/solenoid for the rear ABS loop is sticking open, you wouldn't have rear brake. Each wheel has independent ABS.
It could also be that the rear master is failing, though I suspect that isn't the case since it's back to normal. Masters usually slowly degrade, and once they start to fail they don't usually recover normal operation.
Either way, I wouldn't ride it till it's fixed.

:steps up on rickety soapbox:
It should also be noted that coasting in neutral is a poor practice. It leaves you vulnerable. You lose precious time putting it back in gear, if there's a need to change speed. It's kind of like carrying a gun without a round in the chamber. Sure, you can, and some do, but there's a time penalty when you need to use it. It could cost you your life.
Please forgive me, as I don't like to read about the loss of another rider due to something they could have controlled.
OK, I'm off my soapbox... as you were...
 

WJBertrand

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A good flushing, bleeding fluid replacement sounds like the best idea. The fact that the issue disappeared makes me think about random contaminates in the fluid that perhaps momentarily worked into a place that interfered with normal function somehow.


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RollieFree

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A good flushing, bleeding fluid replacement sounds like the best idea. The fact that the issue disappeared makes me think about random contaminates in the fluid that perhaps momentarily worked into a place that interfered with normal function somehow.


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Very possible and I will do just that this weekend. The bike has less than 10K on it but it is 8 years old. I talked to the service dept at the local dealer who I have found to be extremely helpful in the past. He said since it returned to normal, it was most likely an electronic glitch of some kind but even a single pinhead size air bubble could cause it.
RF
 

Squibb

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Very possible and I will do just that this weekend. The bike has less than 10K on it but it is 8 years old. I talked to the service dept at the local dealer who I have found to be extremely helpful in the past. He said since it returned to normal, it was most likely an electronic glitch of some kind but even a single pinhead size air bubble could cause it.
RF
Personally I don't find the dealer speak reassuring, so I suggest strongly that you don't get drawn into any 'dolittle' plan.

This could be the first sign of a dangerous condition developing - get the fluid changed, the system bled & the ABS pump cycled. Then let's hope that cures the problem.

BTW, you still haven't answered the questions posed in #3 - we are all trying to offer help, but we aren't clairvoyant.
 

jbrown

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...
This could be the first sign of a dangerous condition developing - get the fluid changed, the system bled & the ABS pump cycled. Then let's hope that cures the problem.
...
I *think* this was a one time event, so it will be pretty hard to know if any change cures the problem.
 

RollieFree

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Personally I don't find the dealer speak reassuring, so I suggest strongly that you don't get drawn into any 'dolittle' plan.

This could be the first sign of a dangerous condition developing - get the fluid changed, the system bled & the ABS pump cycled. Then let's hope that cures the problem.

BTW, you still haven't answered the questions posed in #3 - we are all trying to offer help, but we aren't clairvoyant.
Yes. It works normally.
I will get to the bottom of it.
I am not worried about it. I am not riding the bike until it is addressed.
I am competent. I simply asked if anyone had ever encountered this.
I do not get sucked into dolittle plans.
I have built dozens of motorcycles in my life and traveled somewhere in the neighborhood of a half million miles on them.
I get it.
RF
 
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