Front brakes not working

[SilverBullet]

2013 Tenere bought new end of January, 3,000 miles on it at time of incident.

Last month on my last day of riding dirt in MS my front brakes went out completely. I had just passed through some slippery mud and after the first or second application the front brake failed. Figured a sensor got mucked over with mud or something and my buddy said continue to ride it will clear out. Well it didn't and the front brake lever continued to pull all the way to the throttle grip with zero resistance. Back brake operates normally at all times. If I turn off the ignition I can pump front brake lever and get seemingly normal front brakes back. Turn on the bike, ABS light on and still normal. Ride the bike 5 ft. ABS light goes off and front brake bottoms out again. So I pull the ABS fuse, ABS light stays on, but lever still bottoms out after a few feet.

Rode another 100 miles of dirt that day using rear brake only and the following day rode the 600 miles home. Thorough washing of the bike removing all traces of mud and still the same thing. Have rode just a few times after washing, approx 200 miles and still the same. So today finally my scheduled appointment with the dealer came. I waited on the bike thinking the diagnostics machine would identify the cause. After approx 1 hour the service writer comes to me and says they found the problem, a dented and out of true front rotor. So I go back to the service bay and look at my bike. Sure enough I see a decent little dent on the rotor and we spin the front wheel and I think I see a little wobble coming from it. Ok an issue I say but I can't tie that to the brake failure. The service writer starts into an explanation that the rotor being bent generates too much friction and heats up the brake fluid creating brake loss. I snicker and say is that why when bike sits overnight and I pump lever back up to get front brake and then roll 5 ft until ABS light goes out thats why brake fails. That 5 ft creates enough heat to disable brake? So song and dance after that but sticks by the mechanics diagnosis that nothing is wrong with the ABS system or hydraulics and my brake problem is caused by the rotor dent. And of course since damage was caused by myself it is not covered by the Yamaha warranty. After riding home 25 miles on the freeway doing 75 mph both front rotors were cool to the touch and no difference in temperature between the two. Rotor is not in stock and only one available in the US (Wisconsin) so a week away with shipping so I don't leave the bike and don't order part or agree to repair work. Plus I'm still strongly doubting their findings and making it clear to them as well and advise I will find another Tenere to swap front wheels with to verify if their diagnosis is correct. Swapping wheels the problem should follow to the other bike and mine should be corrected. Then I ask the other service writer what if the rotor is not the cause? Will I get the evaluation charge returned? Service writer said without directly answering me that the mechanic has been with them for 17 years and is seldom if ever wrong, the best guy they have.

Here are the photos. What does the collective think? Anyone in the Houston TX area that I can bribe with beer or anything else to do a front wheel swap over and then quickly swap back again after verification? I'm starting to worry that this will drag on and impact my Romney trip plans.





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[yz454]

None of that has any thing to do with the brakes . They work key on or off . Bleed the system .

 

[tubebender]

If the disc was bent it could push the piston back and initial application of the brake could cause the lever to pull all the way back to the grip.
But you should be able to pump it 1 - 2 times and have brakes.

If the fluid boiled (which I doubt), it could cause 'spongy' brakes.

Not to mention these are linked brakes, so it should have applied some rear brake.

I agree with yz454, bleed the system first.

Oh, and go back and ask the mechanic what the run-out numbers were. I'll bet he'll have a blank look on his face.

 

[EricV]

I agree with the previous two replies, and I'd want to check the wheel bearings too, just to be on the safe side. ABS on, off or failed should not impact lever feel. But a wow in the rotor will continually push the piston into the caliper, but also will show up as heat and usually heat affected areas on the rotor.

That this appeared to come on suddenly is interesting. If something caused the brakes to drag during your mud riding, it could have simply boiled the fluid. It happens. First step is always flush and bleed the brake system.

 

[SilverBullet]

Thanks guys, replies have been helpful.

No heat whatsoever on the brake components, 25 miles at 75 mph+ and both rotors and calipers were cool to the touch. And it was 85 degrees today. Fluid level is fine and no air in the lines. If I pump the brake it isn't a gradual pump up like with air in the lines and then finally a hard lever. It is 2-3 pumps with absolutely nothing and then normal brake lever with no spongy feel. Now that you guys mentioned the bump in rotor pushing the piston back it makes sense to me. Just like when I remove a wheel and spread the brake pad gap to make re-install of wheel easier. Zero brake feel and then bingo full brake back. So now thinking maybe the ABS light and ignition switch on are a red herring. Could be the same distance to turn off ABS light is also enough to rotate wheel to bump in rotor causing lever to bottom out. Tomorrow I will do some more testing (pushing and braking) with key off to test it out.

Any hope that I could straighten out the rotor or is that just a waste of time? Are Yamaha rotors at $180 the preferred or any better options out there?

What still is a mystery is what caused the hit to the rotor. Bike never went down, riding was all tame dirt roads and nothing rocky the entire ride. Front wheel wasn't even close to that depth in the mud. Or maybe some foreign object buried in the mud got kicked up by the wheel?

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[scott123007]

It sounded like his diagnosis was correct until he said it was heat related. If you have a bent disk (and it would be noticeable when you spun the wheel) your lever would get hard after a couple of pumps, but only when you were stopped. As soon as you move again the bent disk would push the pads back and you would lose your brakes. You would not get brakes again until you were stopped. Disk runout would probably have to be in excess of .030" though, which would be very noticeable when you spun your wheel.

 

[jbrown]

A warped or bent rotor can certainly push the piston back into the caliper and create a "lever to the bar" situation. If you pump it up to get the brake back, then just let it sit for a minute with the lever released and no wheel movement, does it still feel normal when you pull the lever again? Does it go back to "lever to the bar" if you just spin the wheel while on the center stand without the engine running?

 

[limey]

It's the ABS unit I had the same problem two years ago. You can bleed the snot out of it and it will only last a few miles .I had it replaced at the Ouray get together and lost two and a half days riding trying to convince Yamaha canada and USA.

 

[offcamber]

It would seem the best course of action at this point is to replace the rotor (which needs to be done anyway) and bleed the system. Once you eliminate those two things and the problem still persists you can go back to the dealer. There is enough evidence it could be the rotor, but just as likely the ABS system.

Good Luck

 

[Checkswrecks]

You can put some marker (not paint) on the rivets and radial lines out from the hub of the rotors., turn the wheel, and see if you rub it off in a local spot.

Starting on page 8-97 of the service manual is a trouble-shooting flow chart and process for the ABS system. I'd start there.

 

[Dogdaze]

Silly question, but if you just bought the bike in Jan, albeit a 2013, surely it's still covered under warranty? Take the thing back to the dealer and let it be their problem, unless they gave to the 'Rose and Crown' warranty (pub at the end of the road, warranty expires when you reach it)?

 

[SilverBullet]

Silly question, but if you just bought the bike in Jan, albeit a 2013, surely it's still covered under warranty? Take the thing back to the dealer and let it be their problem, unless they gave to the 'Rose and Crown' warranty (pub at the end of the road, warranty expires when you reach it)?

I did take it to the dealer for a warranty repair. They informed me that rotor damage was not covered by warranty (I agree) and that was the sole cause of my problem (didn't agree at the time due to their heat and fluid boil explanation). My out of pocket repair estimate to fix was over $500. If that didn't fix it then they would proceed with warranty inspection and repair.

I will test a couple things on the bike as soon as I can get to my storage garage this morning. Need to check it out with front wheel up, key off and bike static. I'm thinking rotor is the answer now and the dealer just gave me the wrong reason why making me doubt their diagnosis. I'll have an update post in a couple hours.

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[Dogdaze]

Agree rotor damage is not a warranty claim, if that is the issue then needs a fix, but did something make impact to cause the damage? rock or similar?

 

[dcstrom]

Complete BS about the rotor - would have to have a very visible warp to do anything like what you're describing. Even then I doubt it.

BUT you probably have to replace the rotor before they will look any further. Can you borrow a wheel from somebody to try? I'm 110% confident that this won't fix the problem, and the other person with your wheel won't inherit a problem. THEN go back and say, it's not the rotor... now please replace my ABS unit (you stupid motherf%*#kers) (ok you don't have to say that last bit...).

Or just take it to another dealer, with your rotor still on it. They may not notice it, or they may not be idiots and will know it's not the problem.

 

[SilverBullet]

Well after some testing I believe it is definitely the rotor now. Dealer was right but just for the wrong reason. I jacked up the front wheel, pumped the brake up to normal lever pull and spun the front wheel. Less than one complete rotation and the brake lever sunk to the grip. I repeated this in small increments and lever stayed normal until caliper passed the area on rotor that was visibly impacted. I then got a straight edge out and compared different spots on the rotor for flatness. Nothing super accurate but still showed a big run out at that impact point on rotor. Gives new meaning to the term wave rotor. Pictures are not the best but give you an idea. Both photos had the same light shining up from the ground although first photo you can't tell because the straight edge is so tight against the rotor.

So looks like a new rotor will be ordered. I am thinking to take it off today and see if I can't beat it some with a soft faced hammer enough to get front brake functional again. At least that way I can ride for the week or so it takes to receive the new rotor. Riding this bike with rear brake only you really need to be careful, stay a gear low, downshift excessively and plan your stops in advance. It is really not safe to ride without front brakes.




What I hit to cause this I have no idea. Must have been something buried in the mud I guess.



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[Dogdaze]

I would probably not risk riding it, just get a new disc then ride. In the first instance the feeling of a warped disc would drive you nuts...........

 

[Derekj]

Here is what I'd do. I would put the bike on the center stand and disable the ABS, then go for a little ride to see if the brakes work. If they do then obviously its the abs. I would also take the rotor off after my test and lay it on a flat bench and beat it with a rubber mallet to straighten it for more testing purposes, while you wait for a new one.

 

[Koinz]

Here is what I'd do. I would put the bike on the center stand and disable the ABS, then go for a little ride to see if the brakes work. If they do then obviously its the abs. I would also take the rotor off after my test and lay it on a flat bench and beat it with a rubber mallet to straighten it for more testing purposes, while you wait for a new one.

I don't know if disabling the ABS would help, but I would definitely try to straighten the rotor out with a hammer. I would even go so far as leaving it on the bike and finding the bend and gently tapping it until runs relatively true. A dial indicator would be most useful in this situation if you have one.

 

[dcstrom]

Ok so I was right! you DO have a very visible warp. Still surprised that it would cause you to lose ALL braking though - I've ridden bikes with warped discs and the worst thing is feeling a pulsing at the lever. It's hard to imagine the warp being so bad that when the disc pushes the pad back, the pressure at the lever doesn't recover almost instantaneously. And you said that when you lose the brakes, even when you pump it, it doesn't recover?How could that be anything to do with the rotor? I hope it is the rotor, means it's a easy fix, but I still have my doubts...

 

[SuperTenSteve]

I have not checked but an aftermarket rotor might be less expensive or the same.