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Discussion Starter #1
Took a ride on my facelift 2004 and stopped at my destination after half an hour.
When I got back ten minutes later the ABS light initially started flashing slowly as it does and as I drove off instead of switching off, started flashing fast. The brake booster servo was not working and I stopped and switched off the ignition - first time I restarted it continued flashing fast and then second time heard the wining sound as the booster servo kicked in and the light went off.
All was fine for the balance of the ride.
Any suggestions or thoughts would be appreciated.
 

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I don't know if your servo is failing but I hope you don't have to take the bike to bits to get it checked like I am currently going through as you can see from the photo. The servo is at the top left of the photo sitting on the floor waiting to be packaged up and sent for testing.
 

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I don't know if your servo is failing but I hope you don't have to take the bike to bits to get it checked like I am currently going through as you can see from the photo. The servo is at the top left of the photo sitting on the floor waiting to be packaged up and sent for testing.
Your wife must be very understanding allowing you to pull the bike apart in the loungeroom like that. :grin:
 

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😀 yes looks like that but she is not that understanding, Old carpet on garage floor to catch the various drips from any leaking fluid.
 

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2005 K1200LT
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Also a weak battery can cause a temporary fault like what you had. To confirm try several hard stops in succession and see if it returns. This will load a weak battery down.
 

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Discussion Starter #8
Before assuming the worst, check the brake fluid levels in both reservoirs.
The left brake reservoir was indeed low and in fact topped up both. The light has not come on again.

Could there be a leak - what should I be looking out for?
 

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The left brake reservoir was indeed low and in fact topped up both. The light has not come on again.

Could there be a leak - what should I be looking out for?
You can check for leaks but you should also check your brake pads as they could be worn enough to keep the pistons pushed out further.
 

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The left brake reservoir was indeed low and in fact topped up both. The light has not come on again.

Could there be a leak - what should I be looking out for?
You said the left reservoir, was it one of these on the ABS ? These are the only reservoirs that are monitored. Also on the face lift these sensors only fire off when the pads are very worn.
 

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Discussion Starter #11
Yip not so straight forward - the problem is still evident.
Many posts reflect and upgrade to braided hoses - may I ask why or what's prompting it ?
She's just been for service so assumed the pads were ok but you know what the say : ass - u - me !!!
 

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Discussion Starter #12
You said the left reservoir, was it one of these on the ABS ? These are the only reservoirs that are monitored. Also on the face lift these sensors only fire off when the pads are very worn.
The Reservoirs on the handle bar was what I was referring to ?
Now i'm totally confused ???
 

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You said the left reservoir, was it one of these on the ABS ? These are the only reservoirs that are monitored. Also on the face lift these sensors only fire off when the pads are very worn.
That picture looks familiar. :grin:
 

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The Reservoirs on the handle bar was what I was referring to ?
Now i'm totally confused ???
You earlier said the “left” reservoir and there is no left brake reservoir on the handle bar. The left handlebar reservoir is for the clutch. Since you said “facelift” 2004, I am assuming you mean your bike has the iABS like my 2007. If that is the case, there are four brake fluid reservoirs, one for each brake circuit on the LT. These are: Front and rear control circuits and front and rear wheel circuits. The front control circuit reservoir is with the master cylinder on the right handle bar. The rear control circuit reservoir is under the seat on the right side of the bike and is cylindrical with a screw on cover. The two wheel circuits are on top of the ABS module as shown in the picture that John posted, which I think is of my LT from the looks of it. Ignore the red arrow as that is pointing to the ABS electronics connector. Look at the funnel which is, I believe, in the near side reservoir. I would have to look up now which is front and which is rear, but one is also taller than the other.

The fluid levels in the control circuits are not monitored, only the levels in the wheel circuits on top of the ABS module. The caps on these have breather hoses attached to them. Before you remove the caps to check or add fluid, THOROUGHLY clean all of the areas around and above the cap (subframe, wiring harnesses, etc.). I blow mine off with compressed air, then wash with soap and water and gently rinse (no pressure washers), let dry, and then blow one more time with compressed air. You want this area operating room clean before you remove the reservoir caps.

This is much more work, but the best way to fill these is to fully compress the brake pads in all calipers, use the funnel provided by BeamerBoneYard (I cut mine and added clear plastic hose as I could not get it aligned as it came) and then fill the reservoirs until the level is just below where the bottom of the cap will fit when screwed back in. If you do that, you will have enough fluid to completely wear out the pads and not trigger a low fluid level. Any less fluid, and you risk alarms as the pads wear down. If you don’t compress the pads and fill the reservoirs, then next time you compress the pads, you will make a mess when you push the excess fluid out of the ABS module when you compress the caliper pistons.
 
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