Bad ABS hydraulic unit/module 2007A, per Yamaha dealer

I have a 2007A with 40K on it. A few months ago the front brake lever started requiring it to be pumped 2 or 3 times before it would build up pressure. After approx 30 seconds pressure would drop and the bike could be rolled while still having the lever fully applied.

I checked the fluid level and it was full. I bled the system, the problem was still present. I took the bike to my local Yahama dealer. After a few days they said the front master cylinder needed to be replaced. I paid $89 for a diagnosis and I got the bike back from the dealership and ordered a new OEM master cylinder and installed it myself. To my surprise the problem occurred exactly as it did with the old master cylinder.

I took my bike back to the same dealership. After having the bike for over a month and having to bring in a "Yamaha rep", I got a call today saying that I needed a new ABS hydraulic module (3P6-85930-0900).

I was quoted the following:

$500 to put the bike back together as it sits

$900 to install and program a ABS module purchased and provided by me, either new or used. However if that part does not work or fix the problem I still have to pay them

$2300 for them to get the part $1550, program, and put the bike back together

My confidence in the dealer is not too high because I already replaced the master cylinder, which was not the issue. Their own mechanics could not figure out what was wrong with the brakes and had to bring someone from Yamaha in. I would like a second opinion, but then I have to pay $500 for them to put the bike back together and then pay for someone else to diagnosis it.

Long story short, I was not expecting this. KBB trade in is $4500 and retail is $6600. I am not sure if I should shell out the money and have them fix it, see how much they will give me for the bike as it sets, or etc?

Any suggestions? Anyone else had this issue?

I'm guessing that it isn't the ABS module. Failure of the module usually just results in a lack of functional ABS, not a brake lever that goes to the bar without effect. My bet is on an air bubble somewhere in the system. In the ABS block or at the "tee" where it splits left and right. These can be difficult to bleed completely. Sometimes it helps to bungee the brake lever to the bar overnight. Alternatively, a Mityvac may be able to get enough flow velocity to move bubbles along.

I have never heard of this issue with a Gen II FJR.

Have a really good look at the brake lines as well. If you had a leak, it would be immediately obvious but if a line were bulging under pressure, it could show a similar effect.

RossKean said:

I'm guessing that it isn't the ABS module. Failure of the module usually just results in a lack of functional ABS, not a brake lever that goes to the bar without effect. My bet is on an air bubble somewhere in the system. In the ABS block or at the "tee" where it splits left and right. These can be difficult to bleed completely. Sometimes it helps to bungee the brake lever to the bar overnight. Alternatively, a Mityvac may be able to get enough flow velocity to move bubbles along.
I have never heard of this issue with a Gen II FJR.

Have a really good look at the brake lines as well. If you had a leak, it would be immediately obvious but if a line were bulging under pressure, it could show a similar effect.

Click to expand...

I initially thought there was probably air in the system, but the system has been bled no less than 5 times by myself and the dealer. I am not sure if they used a Mityvac or not. There are no leaks and the lines have been checked for bulging, the dealer stripped the fairings and everything off the bike.

The rear brake pedal operates as it should with no issues.

Is it possible to run brake lines from the MC directly to the calipers, and bypass the entire ABS system altogether?

If the brake fluid is not leaking away somewhere (easy to check) and the level is not dropping in the master cylinder - I would not be looking at the ABS module.

"A few months ago the front brake lever started requiring it to be pumped 2 or 3 times before it would build up pressure. After approx 30 seconds pressure would drop and the bike could be rolled while still having the lever fully applied".

I would be looking very carefully at the master cylinder, it sounds to me like the fluid is bleeding back into the reservoir.

Donal said:

I would be looking very carefully at the master cylinder, it sounds to me like the fluid is bleeding back into the reservoir.

Click to expand...

I was considering the MC to be the primary culprit as well but the OP said he had the same symptoms before and after replacing the MC. If not the MC, still thinking a fugitive bubble somewhere.

Ionbeam did a great article on how to run the diagnostic for the ABS that cycles the ABS module. If it can be activated and is moving, it most likely isn't the problem. Also a failure i the module should cause a diagnostic error code. I would not spend anything until you completely run through this diagnostic.

I agree with the master cylinder folks. Maybe a bit of debris has gotten trapped under the plunger cup allowing fluid to get back past the rubber cup or seal or whatever they use. I suppose it is possible for the ABS module to have fluid easing back past the plunger or whatever it is in the ABS module the same way it can in the master cylinder. At this point I think I would open the master cylinder to make sure it is pristine inside. If that is OK then find a way to do the same as much as possible for the ABS module.

or take the bike on a dirt road and hammer the rear brake at @ 25 mph....if the ABS cycles it should be fine [i do this frequently anyhow just to exercise the ABS unit and this is not hard of unsafe to do]...in any case the stealer wants to bend you over for $500 to put the bike back together..

there is a proportioning valve between the rear and front brakes which allows rear brake application up to a preset pressure which allows rear brake application without front brake application....[brakes are linked] might want to look at that...

lnewlf said:

or take the bike on a dirt road and hammer the rear brake at @ 25 mph....if the ABS cycles it should be fine ...in any case the stealer wants to bend you over for $500 to put the bike back together.. 


there is a proportioning valve between the rear and front brakes which allows rear brake application up to a preset pressure which allows rear brake application without front brake application....[brakes are linked] might want to look at that...

Click to expand...

The OP is concerned with the front brakes, not the rear. the ABS circuits are separate. Also, the rear brake is linked to ONLY the lower right front piston; not the front braking circuit. When the front brake is applied via the lever, it does not have any effect on that piston at all - consider it to be part of the rear brake.

After reading the comments here and everything else I can possibly find on the topic, I have SERIOUS doubts that the dealer and/or Yamaha rep that was brought in ran hydraulic unit operation test as outlined in the service manual page 4-60. In fact the dealer told me they never cycle the abs as part of the brake fluid change process.

They also told me a major delay in diagnosing the problem was because they did not have and were having trouble locating an analog code reader. However, they never expressed if there were codes present.

I think I am going to print off various articles on the subject matter and take my service manual to the dealer tomorrow and have a chat. I want them to perform the hydraulic unit operation test in my presence.

If test fails, then should I feel fairly confident the hydraulic unit is bad and needs to be replaced?

Even if the ABS module is bad, it shouldn't do what you're describing. Default is for the brakes to work to lockup. All the ABS module does is intervene during that process. I'd be very surprised if your ABS module has anything to do with this. You would also be the first EVER to have this issue. Given that the FJR has had ABS available since 2004, and on every bike sold since 2006, for you to be the first and only owner to see this is very hard to believe.

I'm agreeing with the stubborn bubble stuck somewhere or something going on with the Master Cylinder.

HotRodZilla said:

Even if the ABS module is bad, it shouldn't do what you're describing. Default is for the brakes to work to lockup. All the ABS module does is intervene during that process. I'd be very surprised if your ABS module has anything to do with this. You would also be the first EVER to have this issue. Given that the FJR has had ABS available since 2004, and on every bike sold since 2006, for you to be the first and only owner to see this is very hard to believe.
I'm agreeing with the stubborn bubble stuck somewhere or something going on with the Master Cylinder.

Click to expand...

what he said.

ABS electrical/mechanical default is supposed to be stopping the machine when brakes are applied. I would venture a guess that your M/C needed service or rebuild, or replacement and now that that has been done there is air in the system.

A good method I've found is tapping the brake lines with a screw driver handle to get the air bubbles moving UP.. start at the calipers and goe up s far as you can to the M/C. Get the cover off the m/c so that you can watch for bubbles. pull the lever SLOWLY to the bar. release the lever quickly so that the lever springs back as quickly as possible. Do this while watching the ports at the bottom of the m/c.When the lever snaps back out, you will see bubbles from one of the ports. squeeze slowly again, release, tap the brake lines, repeat as neccessarryyyy.

From your 1st post and initial description of the problem that sound like a master cylinder that won't hold pressure.

Da wolf

edit, I haven't used these, but I've read some really good things about them on other forums from guys that have. I'll prolly get a set some time in the future, but bleeding brakes has never been an issue for me.

https://www.speedbleeder.com/

I LOVE my SpeedBleeders. They work great; however, if you have a stuck bubble, you'll need to bleed the brakes backwards. Fluid will need to be pushed UP from the brakes. Remember, the bubbles want to float, and ANY surface tension in a line will hold a bubble tighter than you can imagine.

The line tapping is a great idea BTW...

yup, breaks the bubbles free, pretty much backwards bleeding.

RossKean said:

lnewlf said:

or take the bike on a dirt road and hammer the rear brake at @ 25 mph....if the ABS cycles it should be fine ...in any case the stealer wants to bend you over for $500 to put the bike back together.. 

there is a proportioning valve between the rear and front brakes which allows rear brake application up to a preset pressure which allows rear brake application without front brake application....[brakes are linked] might want to look at that...

Click to expand...

The OP is concerned with the front brakes, not the rear. the ABS circuits are separate. Also, the rear brake is linked to ONLY the lower right front piston; not the front braking circuit. When the front brake is applied via the lever, it does not have any effect on that piston at all - consider it to be part of the rear brake.

Click to expand...

after a rethink forget what I wrote about the proportioning valve...this is all true... however if the ABS could be operated using the rear brake it would show that the unit still functions and it is unlikely that it doesn't work for just the front.

I am getting ready to go to the dealership armed with notes from this forum, other websites, and my service manual. After reading all of your comments I am inclined to have them put the bike back together, bring it home, and run it through everything suggested here.

We shall see.....I will post when I get back from the dealership.

Be careful with sharing "Internet Wisdom" with the dealer (no matter how good that advice might or might not be); especially if you ever plan to use them for future work!

They won't appreciate it and they will regard you as an idiot - no matter how well informed you are.

It has been suggested there is a way to bypass the ABS module to the front wheel or front and back wheel. This would obviously result in the lack of ABS on at least the front wheel.

Anyone heard of someone doing this or how it would be done?