[kamike]

Greetings
It has been a busy summer. Worked hard, rode lots.

I took our 03' K1200LT to the local dealer for the 12k mile "inspection." (Bought it new last November). Valves were all in spec, and all seemed fine except for a leaky rear seal. When I picked the bike up the rear brakes sqealed, and mileage decreased 20%. Upon inspection, after several hundred miles, brake dust was all over the rim, and the rear drive case was hot. Not good.

Back to the dealer, where they replaced the pads and inspected the brake calipers/pistons. They did not find a problem. After this, all seems to work fairly well except for an occassinal wierd clatter sound at the rear rotor when backing the bike up (manually).

Any ideas? It seems to me that a piston may be sticking. Are there known issues that I may not be aware of?

 

[levithornton]

Brake Piston

Pretty sure it's your piston sticking ever so little. We have a '05 K1200LT with front brake: two, four-piston fixed calipers, 12.6" dual floating rotors, full integral ABS and rear: single, four piston fixed calipers, 11.2" single fixed rotor, full integral ABS. With less than 500 miles when new, had the same problem. Local dealer replace rear pistons and solved the problem. Dealer said if they are sticking any, would cause this. Hope this helps. Levi

 

[ATFLT]

A piston has to be sticking. If it was something like the master cylinder or slave not releasing all the pressure then you should have the same problem on all three brakes.

 

[Steve_R]

Rear Brakes

After this, all seems to work fairly well except for an occassinal wierd clatter sound at the rear rotor when backing the bike up (manually).

Since your bike is an '03 and if you're really hearing a clattering sound, then I would suspect the rear rotor to be the issue and not pistons in the caliper. There are know instances of the rear rotor float being more than it should be causing a clattering sound.

If you hear a dragging sound, then I would suspect a piston to be sticking. But a little bit of drag is normal.As far as I understand disc brake principles, the pistons never really pull the pads back. The run out in the rotors force the pistons back as the wheel turns.

I'm not a disk brake specialist and I didn't stay in a Holiday Inn last night, but that could all change today.

 

[Kbiker]

Ok first time on. 2yr 06 k1200lt owner back breaks sticking
Today.Very disappointed with only 19000 miles. Guess I will try the
Clean up job first. After that don't no.

 

[Kbiker]

Hello is anyone out there.I need help. Want to go
Riding tomorrow.

 

[zippy_gg]

Hello is anyone out there.I need help. Want to go
Riding tomorrow.

Well? Have you competed the cleanup job?
remove pads, remove rear caliper (bolts only, not the brake line), use brake cleaner where the piston seals are BEFORE pushing the pistons back in a little (using the right tools and some caution). Re-install calipers, then pads, starts engine, squeeze front brake lever, then press on rear brake pedal to push the pistons back out and eliminate the gap between pads and rotor. Test ride! Report back and well take it from there!

 

[ksbaltz]

OEM brake lines are recommended that they be changed every four years. If your lines are older that 4 years, then your sticking problem could be caused by your brake lines failing. The inside liner is collapsing...this would cause your pads to stay pressed up against the rotor(s). Some one on this forum posted a brake test to diagnose this kind of problem..I don't remember the procedure off the top of my head...so I won't recommend how to do it.. Do a search on collapsing brake lines and see what pops up.

IF the noise you hear from the back of the LT sounds like a clinking bell sound...especially at low speeds...it is the floating rotor at the rear drive assembly.. The rotor is flopping back and forth and it is making the noise...some have put some time of flexible space to mute it...don't know how it is done or if it works...If you wear a helmet and play music....you don't hear it as much...
Stuck pads would be a dragging sound, not a clanking clinking bell sound....If your calipers are not tightened down at the correct torque and are loose well that my be a cause. The pads do not release completely from the rotor, there is a slight pressure, but no drag...it is basically a tight fit.

I don't know how hot the brakes get when running normal with no brake being applied...someone else might know...then you could run the bike and use engine braking to stop and check the temps on the calipers....but that could be very subjective also...no brake expert here...just shooting spit wads at the wall to see what sticks.

I can usually get myself help from all the great people here on the forum. I learn by doing.

 

[Kbiker]

Hello is anyone out there.I need help. Want to go
Riding tomorrow.

Today is the day. Maybe I can figure them out.

 

[Kbiker]

Today is the day maybe I can figure it out

 

[gary45]

Hypoid gears create a lot of heat when vehicle is in motion, FD will always be hot. If a problem is suspected with the brakes put the bike on center stand, rotate wheel, it should rotate easily, with right hand press down on brake pedal and you should not be able to rotate wheel but as soon as pedal released wheel should rotate, brake pads may have slight drag.

The piston O rings inside the caliper harden with age and cause restricted motion resulting in too much drag. If the lining of the brake hose is collapsing the brakes will not release unless bleeder is loosened to release brake pressure, brake hose lining collapse is not very common.

 

[Kbiker]

No go cleaned and worked em over and over
Took it for a ride did not touch back brake
Got home pads pressing against rotar just
Enough to heat em up. Never seen anything like
It. I guess it's off to bank then dealer.

 

[gary45]

No go cleaned and worked em over and over
Took it for a ride did not touch back brake
Got home pads pressing against rotar just
Enough to heat em up. Never seen anything like
It. I guess it's off to bank then dealer.

When on the center stand how much resistance is there manually rotating wheel, all three of my k's got real hot from FD normal temp - when sitting on level ground brakes off do you feel any initial resistance moving back and forward with feet

The rear rotor gets hot from the FD, very little air flow on wheel and FD

 

[Kbiker]

Sitting on CRT stand. Eng not running cracked open both bleeder valves one at time.less than 1/8 oz each loss. Made no diff. Pads did not move back any. Could still feel drag. Took a short ride started heating up agin.I think the prob is in the rear brake pedal master cyl. What do you think. Everything on brake sys. Seem to be working fabulous / servos front brakes etc. I don't want to take it to dealer what a joke. I. Guess I will learn lots about this Hydraulic Technology.

 

[zippy_gg]

If you have not replaced the brake lines, this could be your issue.
I had a similar problem on my 05 LT and it seems the pistons did not retract and there was a constant drag. Replaced the line with a SS braided one and the issue is gone.
In fact I replaced all soft brake lines with new ones as I also developed a leak on the bottom connector of the front master cylinder line.
Old rubber expands, crud builds up, and other bad things happen over time so the lines need to be replaced as part of preventive maintenance, and definitely when approaching 8-10 years of service. I think yours are overdue.
Look into the kit from Spiegler, around $230.

 

[Kbiker]

Sounds like a plan. Thanks

 

[jzeiler]

Bear in mind you have linked brakes so not touching the rear pedal is meaningless since they will always be applied when hitting the fronts. The rear master cylinder does not feed fluid to the rear caliper but it controls the servo for the rear brakes. There will always be a little drag on the rear brakes but you should be able to easily overcome it with your hand moving the rear wheel. If you can't then you have a problem.

+1 on replacing the lines. I just finished my 05 and I cut one of the factory lines open. Very soft inner liner and two layers of fiber weave around that and a thick rubber casing. The inner liner appeared to be saturated and the fiber was discolored. Glad I got rid of them.

 

[Kbiker]

Any idea on cost for dealer to replace brake lines.and then fill and flush system.I could change lines but the flush and fill I don't no.

 

[gary45]

BMW means bring more money

 

[zippy_gg]

Any idea on cost for dealer to replace brake lines.and then fill and flush system.I could change lines but the flush and fill I don't no.

Where are you located? There might be a local member who could assist.
I can help if you are in SoCal.
Also a dealer will replace your brake lines with BMW parts that cost more than the set from Spiegler, but the new lines will last a good 8 years again...