Loss of rear brake on 2021 T7 ?

[NeilW]

Please no one respond with " stop riding the rear brake" 

What did you tell the dealer when you brought it to them?

What did the dealer do?

If your dealer did something please advise the dealer name and location.

 

Thanks for staying on topic on this one.

[Lewie]

So it’s a 21 plate with a non working back brake? - would you not just tell them that and surly it’s covered under warranty 

[NeilW]

1 minute ago, Lewie said:

So it’s a 21 plate with a non working back brake? - would you not just tell them that and surly it’s covered under warranty 

It has only happened 5x in 5000 miles and 13 months. Works when pressed and then next time it isn't there.  Yamaha dealer will be happy to do a two hour diagnostic at my expense, if they don't discover it. Since it has only happened 5x in 14 months, the likely hood is remote. I asked the service write to bring it up to the Yamaha Rep to note that there is at least one complaint.  It will be warranty when the acknowledge it.

[Ray Ride4life]

The rear brake failed 5 times in 5000 miles, on other words it fails every 1000 miles in the warranty period.
I would say to the dealer fix it and fight it with Yamaha and otherwise give me in writing that you refuse to fix the problem within the warranty period so i or my family can sue you when something goes wrong because of this problem.

 

Mine also seems to loose pressure sometimes but i suspect an air bubbel in my case because if i let go and press again it;s back.
I do want to change the fluid for the racing one because i lost it also one time on the Lyssevegen serpentine. The same problem i also had on my Crosstourer (with the Dot 5.1) and solved it that way too.
Didn't do it yet because i'm not sure what i want to do, change the hose for braided or a rear ABS delete but probably both.

[NeilW]

44 minutes ago, Ray Ride4life said:

The rear brake failed 5 times in 5000 miles, on other words it fails every 1000 miles in the warranty period.
I would say to the dealer fix it and fight it with Yamaha and otherwise give me in writing that you refuse to fix the problem within the warranty period so i or my family can sue you when something goes wrong because of this problem.

 

Mine also seems to loose pressure sometimes but i suspect an air bubbel in my case because if i let go and press again it;s back.
I do want to change the fluid for the racing one because i lost it also one time on the Lyssevegen serpentine. The same problem i also had on my Crosstourer (with the Dot 5.1) and solved it that way too.
Didn't do it yet because i'm not sure what i want to do, change the hose for braided or a rear ABS delete but probably both.

Unless an issue is a known warranty issue, if they can't see it, they can't fix it. It is not 1x every 1000 miles, it is 5x in 5000 miles . I just did 1400 miles and it did it one time but hasn't done it since April.

Others will chime in on their service experience with this issue. I know it is not an air bubble because the rotor is too hot to touch and I wasn't pressing the pedal.

[williestreet]

My guess would be debris/swarf in the master.  Several others have taken their masters apart and found debris.  

 

I would be suggest they pull the piston out of the master to confirm.

If they are not willing to do it I would be ordering a rebuild kit and doing it myself.

Have not checked price on rebuild kit, but usually they are not very expensive.

 

 

[NeilW]

1 minute ago, williestreet said:

My guess would be debris/swarf in the master.  Several others have taken their masters apart and found debris.  

 

I would be suggest they pull the piston out of the master to confirm.

If they are not willing to do it I would be ordering a rebuild kit and doing it myself.

Have not checked price on rebuild kit, but usually they are not very expensive.

 

 

Serious question. Debris causing only 5 failures in 14 months ?

[Jesse]

I know you want it covered but if it can't be duplicated easily and its not a common problem then I'd replace the rear pads with Sintered  pads and  change rear the brake fluid and bleed the brakes on your own. The Sintered pads made the rear brake feel way better. Plus its cheap and all in for maybe 50 bucks. 

 

[DT675]

Personally I don’t trust factory fluid and changed mine front and rear in the 1st year of ownership. Haven’t had any problems in 6k miles anyway.

[NeilW]

16 minutes ago, DT675 said:

Personally I don’t trust factory fluid and changed mine front and rear in the 1st year of ownership. Haven’t had any problems in 6k miles anyway.

About 5or 6 people in all the t7 forums have brought it up. Not many. But all with the same exact complaint out of all the t7’s. 

[Tenerider]

9 hours ago, Hogan said:

Does the brake pedal travel a long way and you get no brakes?

 

What were the riding conditions when all these failures happened?

Would also be interested in this. I guess you realized it in harder braking situations, or when using the rear brake only?

[DT675]

Are you a heavy rear brake user? Could you just be boiling the rear brake fluid and then loosing it? 

 

If not I guess IMO I would still flush the whole rear brake system.  Its cheap and pretty easy to do.  Maybe you will flush out a foreign particle that is causing a random seal problem.  Otherwise as stated, getting warranty coverage on a issue this random is very unlikely, at some point you will probably have to address it yourself.  I would probably be looking at rebuilding the master or replacing it. 

 

Good luck with this. 

[NeilW]

18 hours ago, Hogan said:

Does the brake pedal travel a long way and you get no brakes?

 

What were the riding conditions when all these failures happened?

4x was off road, flat gravel roads- several hours of forest scenery. I always stand. I use the front brake even on steep rocky down hills. maybe 3 or four times during the hours of beautiful scenery I used the rear brake. Then the "next" time I press it, it doesn't grab, so I then consciously press it again to see if it will, and it goes all the way to full extension of my ankle, with zero braking.  The first two times I stopped to find out what happened - ie leak etc and the rotor was burning hot. Waited about 10 minutes - stopped for a water break- and it came back and stayed solid for however long the time was left in the ride, plus riding home - 2-4 hours. Happened 2x on one ride. 

fyi in my natural standing position, the toe of my boot is behind the brake pedal and slightly out side of it.  It has always happened while standing except for the last time:

This last time, on Saturday, I was riding on 50 MPH highways, sitting, with my feet up on my HIGHWAY pegs  for at least 30 minutes- yes I love my  comfort :-). We came up to a small town with a 25MPH  speed limit, so I moved my foot from the highway peg back to the regular peg and pressed on the rear brake, and it was GONE.  I told my riding buddy through our Sena Mesh intercom about it and he told me that Yamaha needs to be put on notice that this is happening because this is a safety issue- so I am trying to gain evidence of others with the same issue. 

[Hibobb]

22 hours ago, NeilW said:

Please no one respond with...

 

I say adjust the pedal 1" lower for six months as a test. Ya it awkward, but usable.

What do you have to lose?

[NeilW]

1 minute ago, Hibobb said:

I say adjust the pedal 1" lower for six months as a test. Ya it awkward, but usable.

What do you have to lose?

Nothing to lose but you have to understand I am not accidentally riding the brake. The last time it happened, on Saturday, I had my boots up on highway pegs for at least 30 minutes. 

[Tenerider]

If the rotor was hot, it means that the pads were in contact with the disk - probably too much pressure in the system (heat?), or another reason,  so they don't return to their open position. The disk might also be slightly bent.

 

Not sure about the brake pad material on the T7, but I know from my own bicycle experience that disk brake pads can overheat and get "glassy" (at least that's how it's called in Germany). They have almost zero braking power (friction) left, but can recover somehow if the glassy surface is scraped off (for example by heavy braking) again.

 

[NeilW]

Just now, Tenerider said:

If the rotor was hot, it means that the pads were in contact with the disk - probably too much pressure in the system (heat?), or another reason,  so they don't return to their open position. The disk might also be slightly bent.

 

Not sure about the brake pad material on the T7, but I know from my own bicycle experience that disk brake pads can overheat and get "glassy" (at least that's how it's called in Germany). They have almost zero braking power (friction) left, but can recover somehow if the glassy surface is scraped off (for example by heavy braking) again.

 

Remember this is 5x in 14 months and 5000 miles. not every ride. My minimum ride is 4 hours, so if it was a bent rotor it would happen on every ride. I was riding 1400 miles, Wednesday though Saturday. It happened ONE time and Wednesday was 4 hours of riding, Thursday was 10 hours of riding, Friday was heavy off road and heavy use of the rear brake due to conditions and 9 hours of riding and Saturday was 10 hours of highway riding and with my feet on the highway pegs, it happened one time. I didn't stop and when I checked it again in about 10 minutes, it was back, but I never stopped. If the rotor was warped, it would have stayed hot...

 

[Hibobb]

Newton's First Law of Motion states that a body at rest will remain at rest unless an outside force acts on it.

Now you just have to find the culprit!

[NeilW]

1 minute ago, Hibobb said:

Newton's First Law of Motion states that a body at rest will remain at rest unless an outside force acts on it.

Now you just have to find the culprit!

Yup. But I am not the only one with this issue in the world. I have seen posts on other T7 forums with the same issue. - but not many. 

[Dougie]

Either way Neil, I’d strip and clean the caliper too. First. A build up of shite may stop it releasing. Also as others have said maybe then strip and clean the system. Bleeding correctly. Preferably with a pressure system. 
put the back wheel up first and action the pedal whilst watching and feeling the caliper. See if it’s free or binding. Clean and retest first though before moving on. As I keep telling my guys bringing me seized equipment. 

[PNGL]

I had a similar issue, but mine was developing slowly. It got very mushy like there was air in the lines. Also, when this was going on, I developed an issue where the ABS light would start flashing to indicate an issue, whether the ABS was on or off. Never lost any brake fluid and never had the ABS activate more than a quick buzz here and there to remind me I hadn't put it in offroad mode when I got to the dirt I was seeking. I point that out because I've read that over-use can apparently cause the ABS pump to overheat and throw up that same light.
After a couple weeks of that ongoing nonsense, I had a mechanic buddy change my tires for me and the rear brake was suddenly completely non-existent. As in, the pedal could be pushed all the way down until it stopped and the brake wouldn't activate at all. I found this out when I picked up the bike and went on the first ride with the new tires and somehow spun the rear on the rim with 36PSI, ripping the valve stem halfway off! He picked me up with a trailer and took my bike back to his house and put my old stock tube back into the new tire. After that, the brakes were/have been perfectly fine. Well, as fine as those abysmally vague stock pads can be. I've had no ABS warning lights, no mushy pedal, and no other problems for the last 2200 miles.
My suggestion is to mess with your caliper and see if maybe pushing the piston back in somehow clears up, or at least helps, your issue. It apparently did with mine. Soon, I'll be putting in the Galfer pads I got from Camel. If messing with the caliper again changes anything, I'll find this post and leave an update.
Good luck.

Edit: After reading through some other comments, I'll point out that mine wasn't the fluid boiling due to a sticking caliper. When mine was completely not working, I rode up Rob's driveway (60ft or so) and at the top pushed the pedal all the way to the stop with no slowing. I figured maybe I just needed to pump the piston back out, so as I was riding down his street I was pumping the pedal all the way down and back up. It never changed. I rode about 15 miles of street and dirt, before ripping off the valve stem and then him coming to get me and switch the tube; some how making the brakes work again.

Edited September 28, 2022 by PNGL

[NeilW]

10 minutes ago, PNGL said:

I had a similar issue, but mine was developing slowly. It got very mushy like there was air in the lines. Also, when this was going on, I developed an issue where the ABS light would start flashing to indicate an issue, whether the ABS was on or off. Never lost any brake fluid, and never had the ABS activate more than a quick buzz here and there to remind me I hadn't put it in offroad mode when I got to the dirt I was seeking. I point that out, because I've read that over-use, can apparently cause the ABS pump to overheat and throw up that same light.
After a couple weeks of that ongoing nonsense, I had a mechanic buddy change my tires for me and the rear brake was suddenly completely non-existent. As in, the pedal could be pushed all the way down until it stopped and the brake wouldn't activate at all. I found this out when I picked up the bike and went on the first ride with the new tires and somehow spun the rear on the rim with 36PSI, ripping the valve stem halfway off! He picked me up with a trailer and took my bike back to his house, and put my old stock tube back into the new tire. After that, the brakes were/have been perfectly fine. Well, as fine as those abysmally vague stock pads can be. I've had no ABS warning lights, no mushy pedal, and no other problems for the last 2200 miles.
My suggestion is to mess with your caliper and see if maybe pushing the piston back in somehow clears up, or at least helps, your issue. It apparently did with mine. Soon, I'll be putting in the Galfer pads I got from Camel. If messing with the caliper again changes anything, I'll find this post and leave an update.
Good luck.

Interesting. The rear stock tire was changed out to MT 21 and then to Shinko ( I write reviews) Has happened with all three tires.  And you will like the galfer pads. Only takes  few minutes to replace them. Just go out to the garage now and do it. Just watch for the flat plate spring

[Hibobb]

There are some "ports" in the master cylinder that seal up during the stroke, then open up "vent" on retraction.

It is possible there is something floating around that occasionally seal up the port and make the pads drag after use. As someone else said, you can try cleaning it. A new rear master cylinder is maybe $130 if all else fails.

 

[Happy700]

An often overlooked component of a brake system is the master cylinder vent port of the lid/cap. It should be checked and ruled out as it can cause the brakes to remain partially on. 

[RIDER GUIDER]

I've had an issue, I boiled the fluid on a spirited set of twisties.  Just riding my T7 like I used to ride a Supersport bike.  Has happened a couple of times, eased off and it cooled down and my brakes came back.  It shouldn't happen to be fair, in my opinion, if they can make an R1 cope with a spirited ride, why not a T7 when it's as important as a braking system?   In this instance I just upped the grade of the fluid to a higher temperature rating.  I'll investigate a pad upgrade next and 'the fix' once I've been convinced it's better, and tried it on a mates bike.  I'm a big user of the rear, especially off road when I'm out on the gravel or similar.  To be fair I don't ride that hard often these days, smelling the roses is pleasant and I like my shoulder blades.   Yours does sound like a different issue though, they're just not returning, got to be some crap the in works if your disk is hot. 

 

Edited February 16, 2023 by RIDER GUIDER