Losing rear brake after a good bleed.

[patrickg450]

Yamaha North America gave me some really good info......

They wanted to have one of their guys check it out, but they did not have anyone (or money) to have it checked out. So the dealer becomes their eyes.....then they told me to work with the dealer. So they never looked at it after saying they needed to look at it .

 

[MikeinNZ]

I curious as to what method you are using to bleed the system? Vacuum bleeder?

Probably something you are aware of already, but when vacuum bleeding you will suck air from around the bleed nipple threads. Bubbles in the fluid don't necessarily mean air in the system in that case. It may only be coming from the loosened thread connection. This can still happen in pressure bleeding when you have a nose on the bleed nipple to watch for air in the fluid, but it's less common since the pressure tends to push fluid out around the threads.

Pretty much the standard response from Yamaha. It's normal to want local eyes on the problem before they start suggesting upper level solutions for what could be a minor issue.

I am pressure bleeding. I spent an hour doing the full procedure last night and got 500meters today with a good back brake then lost it again. I have a blister on my hand I’ve bled the thing that much.
I phoned my Yamaha dealer this morning and interestingly he had no information on his screen for any ABS unit sales to NZ or Australia. The only price he could find was an old price of $3,250 NZD. He is going to contact the NZ tech rep and see if Yamaha can come up with some ideas or a better price. At half the worth of the bike it’s a bit rich I think.

 

[EricV]

Most of the Yamaha ABS blocks I have replaced have been with used ones sourced from a wrecker or ebay. Hugely cheaper. No issues with those.

 

[patrickg450]

MIke I have something to say to you......this was said to me by another member here.


There is no happy ending here, the ABS pump is bad, bypass it or replace it. Yamaha wont do squat either, although they should.

 

[SilverBullet]

I just lost my rear brake also during my last long ride (2013 with 123,000 miles). I can pump up rear brake pedal 5 to 6 times very quickly and get brake back but release brake pedal and it's gone again. I typically cycle the ABS pump every other day or so while riding and only 2 months ago verified the ABS pump unit and compartment was clean and dry. I have yet to try bleeding but suspect I will have the same results as others have. Lucky for me though is I still have 14 months of YES remaining so it will be replaced brand new for free. Glad as I'm not ready to lose my ABS brakes, I can turn it off when desired but really like having it when touring on pavement. Just rode through some snow both in UT and CO last week.

Isn't it funny how the most common Tenere failure besides the CCT is a made in Germany part by Bosch. Probably the only German part on our bikes. Gives me some empathy towards those poor BMW owners.

 

[EricV]

After doing some searches for used ABS units, holy cow! Many are a couple of hundred dollars US, but the Super Ten ones are all north of $1k USD. At that price, I'd be going to the local hydraulic hose shop and getting short hoses made up to bypass the ABS unit. Sucks.

 

[SilverBullet]

After doing some searches for used ABS units, holy cow! Many are a couple of hundred dollars US, but the Super Ten ones are all north of $1k USD....

Used one for over $1,000 is crazy. You can buy a brand new one at RMATV for $919, maybe even cheaper elsewhere.

 

[MikeinNZ]

Thanks guys, the cheapest one I can find is at partzilla bit it will still be $2k NZD landed. I have just bought some 10mmx1 tube nuts and will bypass it till I win Lotto. I’ll make up some U pipes to connect to the manifold just forward of the ABS unit. I see others have double banjo bolted the hoses together but I’ll go down the made up pipes I think.
I’m going to pull the motor off the ABS block and see if the shaft seal can be changed or moved if the shaft is worn. It is peened in from manufacture but where there’s a will there’s a way to re-attach it if it is indeed repairable.

 

[patrickg450]

I just lost my rear brake also during my last long ride (2013 with 123,000 miles). I can pump up rear brake pedal 5 to 6 times very quickly and get brake back but release brake pedal and it's gone again. I typically cycle the ABS pump every other day or so while riding and only 2 months ago verified the ABS pump unit and compartment was clean and dry. I have yet to try bleeding but suspect I will have the same results as others have. Lucky for me though is I still have 14 months of YES remaining so it will be replaced brand new for free. Glad as I'm not ready to lose my ABS brakes, I can turn it off when desired but really like having it when touring on pavement. Just rode through some snow both in UT and CO last week.

Isn't it funny how the most common Tenere failure besides the CCT is a made in Germany part by Bosch. Probably the only German part on our bikes. Gives me some empathy towards those poor BMW owners.

Please file with NTSB, according to the FACTORY MANUAL. A ABS failure will not cause a brake failure, so going by their own document this is NOT suppose to happen.

 

[MikeinNZ]

My vacuum bleeder turned up today so I had another play.
I made up a pipe to bypass the rear side of the ABS unit. Sealed up the bleed nipple with some thread tape and sealed the rear reservoir cap and sucked the system down to 20 inHg. It held at 20 for a good 1/2 hr.
I then made up a blanking pipe and tried to suck the rear side of the ABS unit but it wouldn’t hold and settled at 2inHg.
Something inside the ABS unit is leaking air, my guess would be the seal on the shaft of the motor as everything else is sealed.
I made up another pipe to complete the rear side of the ABS,filled it with fluid and installed the pipe, bled the rear and went for a ride.
The rear brake feels fantastic, obviously no ABS but it’s so powerful it made me smile. Went down a gravel road and fired the front ABS several times and came home with no ABS faults.
I have had air introduced to the front brake twice now when using unified braking so I’ll either have to bypass it, fix it or replace it.
I’ll have a go at fixing it next time I’m feeling brave.

 

[MikeinNZ]

Please file with NTSB, according to the FACTORY MANUAL. A ABS failure will not cause a brake failure, so going by their own document this is NOT suppose to happen.

The worry with this fault is you get no ABS warning light until you are buried in the back of a car with no rear brake!

 

[Dogdaze]

That sucks, that you are having such a sh*t time with just getting the bike too.

 

[Nikolajsen]

Perfect trouble shooting

 

[MikeinNZ]

That sucks, that you are having such a sh*t time with just getting the bike too.

I think I found out why it was cheap... private sale so no comeback

 

[scott123007]

I like the idea of having no rear ABS, ever. I wonder if you can disable whatever tells the ABS pump to unify the braking, then only have front ABS? I say this because something tells it when to unify, because normally, if you apply your rear brakes first, they are not unified.

 

[Dogdaze]

I think I found out why it was cheap... private sale so no comeback

I didn't want to say it, but glad you thought of it as well.

 

[MikeinNZ]

I like the idea of having no rear ABS, ever. I wonder if you can disable whatever tells the ABS pump to unify the braking, then only have front ABS? I say this because something tells it when to unify, because normally, if you apply your rear brakes first, they are not unified.

I see on the wiring diagram the rear brake light switch has an input to the ABS ECU.
I wonder if permanently switching this and then re-wiring the switch and rear brake light would eliminate UBS?
I’m thinking it is UBS that is wearing out our ABS units as every time only the front is used the ABS motor runs to pump up the rear. Unlike a normal system where the only time the ABS motor runs is when it is skidding.
Since having the bike I have adapted my riding to use the rear first which is OK but a bit distracting.
The few times that I have managed to use UBS (ie straight after a bleed) it did feel good as the bike doesn’t dive as much as just front.

 

[patrickg450]

I have my rear brake bypassed right now. Front has ABS and I have ridden it that way for a bit but I will put in a new ABS pump.

To hell with Yamaha.

 

[Thetractorman]

Hi Mike.
I have a 2013 with 50k miles on it. Only just found your post unfortunately. Exactly same symptoms, a second hand rear master AND factory service kit later, I find it's the ABS unit!
The bike cost £6k 4 years ago when it only had 1.5k on the clock, so a new abs unit really isn't a realistic option.
Did your fix work long term?
Sounds like a really good and cost effective idea!
I love the the bike, having already changed the CCT. She's going well this problem aside.
I'm not an aircraft engineer or mechanic, but I'm game. Any more details or pictures would be most welcome.

Sent from my SM-G960F using Tapatalk

 

[MikeinNZ]

Hi Mike.
I have a 2013 with 50k miles on it. Only just found your post unfortunately. Exactly same symptoms, a second hand rear master AND factory service kit later, I find it's the ABS unit!
The bike cost £6k 4 years ago when it only had 1.5k on the clock, so a new abs unit really isn't a realistic option.
Did your fix work long term?
Sounds like a really good and cost effective idea!
I love the the bike, having already changed the CCT. She's going well this problem aside.
I'm not an aircraft engineer or mechanic, but I'm game. Any more details or pictures would be most welcome.

Hi,

The ABS unit repair worked but after 2 months of riding to work and back found the rear brake pedal got slightly worse. I was still using the rear brake first to avoid UBS much of the time.
I went on a big ride with a bunch of guys from work so decided to bypass both front and rear to avoid any issues, most of the ride was on gravel and I prefer no ABS.
That’s how it has stayed.. bypassed.
The machinist at work made the pistons diameter 0.0005” undersized. It doesn’t sound like much but I believe the worn seals need a finished size bigger than original. He has the old pistons and has agreed to make some 0.002” oversized. I will polish as required to get free movement. That was 6 months ago so I might need to shout him some beers and remind him.
For anyone wanting to have a go at fixing the ABS unit my advice would be to buy a new one. Brakes are important, the roller bearing that works the pistons is unobtainable and in my case corroded and worn. This over time will wear away the piston tops and eventually not give the desired throw the pistons need. We ride these machines because we love it and anything that takes away from the experience should be fixed.
In my case $2200 NZD is a fair chunk of money to find, I ride a lot of gravel and that’s why it is still bypassed.