[du907]

I started to bleed the brakes like I do over the winter every year. This is not the first time I have done this. I set all the caliper pistons back flush, set my spacer bars between the brake pistons and disk on front and back brakes, screwed my funnel in the pump, put in brake fluid, had my hose on the front brake nipple. Turned the key and NO, NOTHING, from the pump! No whirl, nothing. Lights come on like normal. This thing just worked last weekend when I started it. A tech guy I know at BMW dealer told me there is a fuse to the pump but I can't find it. I have the workshop manual on disk and can't find it there. Checked the owners manual and it says there are no fuses on this bike. I check the ABS module for error codes with MotoScan and there are NO error codes.
Anyone have any ideas? I have literally NOT touched anything electrical on the bike or the pump or anywhere. Everything up to this point has been all mechanical.
Damn BMWs

 

[du907]

Put a load tester on the battery and it failed. Very weak, almost in the failed area. So, I'm hoping replacing the battery will bring it back to life. I have read that if you have a weak battery it will not run the servo pump. Since I have no error codes, this could be the problem.

 

[du907]

Hey, guys, I really needs some help.
Like I stated above I was bleeding the brakes and the servo motor will not come on when I turn the key. I touched nothing electrical. I have checked the ABS for fault codes and there are none. I have not a single fault codes on the bike except the gas tank is not connected. I just put in a brand new battery and NO change. Had the charger on the charged battery and still no noises from the servo motor.
Any ideas?
Thanks

 

[Fried_Chicken]

Did you recharge the battery like you stated? If the battery is low it won’t power up the servo motor.

 

[du907]

Fried_Chicken,
Thanks for replying. Yes I installed a brand new battery. No change. I just put the gas tank back on. Started the bike and rode it down the driveway. The brake light kept flashing and the servo motor never did come back on. I thought maybe if I started it a moved the bike, the light might go off like normal. But the servo motor never does make it's whiss bang boom noise. Still no fault codes!
shit

 

[Beech]

Your servo brake system is done. Either a rebuild from the german company NE or buy their bypass unit. There are several threads on the forum for this.

 

[Fried_Chicken]

There must be a diagnostic you can do where you manually power the pump.

A tech guy I know at BMW dealer told me there is a fuse to the pump but I can't find it.

Did you ever find this fuse?

Nothing you described should break the servo motor.

 

[Hondakiller]

no hay fusibles en las k1200 ni en las k1300, lo que si existe es un diagnostico para el servofreno en el programa istaD

 

[du907]

no hay fusibles en las k1200 ni en las k1300, lo que si existe es un diagnostico para el servofreno en el programa istaD

Say What?

"There are no fuses in the k1200 or in the k1300, what if there is a diagnosis for the brake booster in the istaD program"

 

[du907]

I have checked everything I can. There is power going to the servo at the plug. I loaded the bike up and took it to the local dealer to have them check it on their system for anything I might have missed. If it turns out to be the servo motor, here is my plan.

I have looked over the brake lines and I believe I can just take the rear brake line loose and attach it directly to the rear brake pedal assembly, the two lines are not more than 2~3 inches apart. I may need an adapter of some sort for the front lines. Line from the servo is on the right, line from the lever is on the left but that line can be moved to the right. Both lines have banjo bolts, so will need to make a female on both sides adapter.
I plan on taking the electrical module off of the servo pump and making a plate for the exposed back to seal it from the weather to keep the brake lights and speedometer working with original wiring harness.
I'm then going to take the servo apart and see if I can figure out what has made it quit. Clean the unit and replace o-rings and check the motors. Does anyone know where to get parts for these motors, like brushes. Seems this could be the problem.
I'm going to have the circuit board checked for failures. If I screw it up, I still have the option to send it off to be rebuilt, when Module Masters accepts new orders. I will just run the bike without the servo unit until I either fix the servo, or have it fixed.
Been riding without ABS all my life. I guess I will be doing it again for awhile.
du907

 

[du907]

Fried_chicken,
There are no fuses. The owners manual says there are no fuses in the system.
Also my Motoscan software reports no fault codes. So I figure Motoscan must not be able to read the ABS good enough or there are no fault codes that report the servo has failed. That's why I took it to the dealer to let them scan it and tell me the bad news. If it turns out it is the servo, then my plan is the above.
Thanks for responding.
du907

 

[Fried_Chicken]

Godspeed!

 

[Mattias_r]

 

[du907]

Mattias_r
Interesting. I bet if it turns out to be the pump, it's the brushes that are worn. Wonder were I can source new brushes for the two motors? I'm thinking way ahead, but from all that is on the web about this seems that is a common problem with the motors. Also there is a part for a different BMW model that is a union for two banjo bolts, one from the handle bar, the other the lines going to the front brakes. I think it's from an R1150 or similar.

 

[Mattias_r]

Usually not even worn, one just siezes in its track, try tapping om the motor.

There are no fuses inte electric diagram, checked for all years and models.

 

[du907]

Good News!
My bike doesn't need a new servo pump! I took the bike to the local dealer to check out why the servo pump didn't come on when I was doing my yearly winter brake fluid bleed. Turns out it was the miro switch at the handle bar lever was out of adjustment. Plus they needed to reset ABS computer (their words). Didn't cost me but 30 minutes labor, good deal and shout out for my local dealer being honest about it all. They did say something about pulling lever with ignition off a lot could throw a code? My Motoscan app continually showed no codes. I wonder if Motoscan can read all the ABS fault codes?
Anyway will pick bike up tomorrow and finish bleeding the wheel circuits and then my winter work is done!
On the road again.

 

[Beech]

Hey, you got to use the front brake moving the bike around, not to sure about that dealer comment. But good he found the cause. Was your brake light on all the time? A malfunctioning switch (or pebble stuck in the rear brake linkage) can cause the light to be on.

 

[Fried_Chicken]

Goes to show how important proper diagnostics is.

Glad to hear it!

 

[du907]

Hey, you got to use the front brake moving the bike around, not to sure about that dealer comment. But good he found the cause. Was your brake light on all the time? A malfunctioning switch (or pebble stuck in the rear brake linkage) can cause the light to be on.

You know, the brake lights did work the whole time. Same switch, interesting. I'm going to pick it up tomorrow, I'll see if I can get some more info.

 

[du907]

Finished the brake bleed today. Did the circuits from the module to the calipers. The servo worked just fine. Installed new pads on the rear. Finished up by installing a metal quick change nipple replacing the plastic one at the gas tank outlet.
Winter work is all done! Come on spring!