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Discussion Starter #1
After installing Progressive Monotubes in my 2013 F6B over the winter I decide to get the bike out today and test. I only rode 1/4 mile and after hitting the brakes could tell there was a problem. The front left and rear calipers seem to stay engaged after applying either front or rear brake pressure. I immediately put it up on the lift and completed a complete brake flush/bleed per OEM manual but experienced the same result. Ive checked every bolt, etc and cannot find the cause.

Anyone ever experience this and can point me in a direction?
 

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The secondary master cylinder on the left front caliper is probably sticking internally or if it was removed/reinstalled the pivot bolt/bearing or the link joint are overtightened/seized or incorrectly installed.
 

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Discussion Starter #5
The secondary master cylinder on the left front caliper is probably sticking internally or if it was removed/reinstalled the pivot bolt/bearing or the link joint are overtightened/seized or incorrectly installed.
Thank you. I had planned on loosening everything up again today and rechecking everything related to the left caliper.
 

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Did u check that bolt that operates the anti dive valve -second master cylinder on the left caliper ?
friend experience similar problem a couple thousand miles after dealer had replaced fork seals, they didn’t tighten that bolt properly and it worked its way out and got jammed and locked the brakes when he pulled into a parking spot.
 

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Discussion Starter #7
Had a little time and conducted the following.
  • Loosened the bolt on top of the secondary master cylinder to ensure it was not too tight and seizing
  • Checked fluid level in both front and rear reservoir to ensure they were not overfilled.
  • Pushed it back off of the lift and coasted freely out into the driveway using only front brake. No problem.
  • Cranked up and headed down the street first using only front brake. Did not feel any residual grab or dragging after release.
  • On return used the rear brake pedal and felt immediate residual drag. Mashed repeatedly to see if that would free up return with no improvement. Brakes dragged the remainder of the way back.
So, something amiss when using the rear brakes only. I have done the full bleed but was advised of a couple of additional steps to include the junction block and the top banjo on the secondary. If that does not resolve I guess it is off to the dealer to determine if this falls under the extended warranty.
 

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It appears you have determined the issue is caused when using the rear brake system pedal. Did you determine if it is only the rear wheel brake caliper "sticking" or if the linked system is causing the front center caliper pistons to also stick?
When on centerstand spin each wheel and check for "drag".
 

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Discussion Starter #9
The linked system is apparently causing the left front to stick as well. Confirmed by the level of heat experienced on both the rear and left front calipers/discs. No centerstand on my F6B.
 

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I guess I shouldn't have said the "linked system" may be causing the caliper center pistons to stick. A corroded/dirty center piston would be activated by the linked system and then the piston doesn't release pressure on the rotor. May be no problem with the "system" only with the piston(s). I seldom use the foot brake pedal much (the prior ST1300 applied plenty of rear brake using only the front lever) which could cause infrequent movement of the front caliper center pistons.
Apologies for the poor explanation, even at this point.
 

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I had a similar problem with my M109R. It was only the rear caliper and after melting two sets of brake pads and disassembling the master cylinder and caliper and all looked good, I found that there was no free play in the pedal. No problem since backing off on the linkage.
 

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I had similar issue - 2008 ABS/nav. turned out is was the front left caliper..and the lower piston. The brake caliper would grip the disc and under hard enough braking would rotate slightly up activating the slave cylinder which applies the rear brake....that is how it is designed. BUT if the front left caliper piston does not retract as it is supposed to, the caliper stays in that upper position on the disc and the rear brake stays on. If you continue to ride, all components in the rear caliper heat up and expand...causing the rear to lock up.
 
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