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Brake vibration

willy

willy

Member
2009 Road King has a vibration when front brakes are applied as the bike slows it becomes more of a pulse.Checked runout on front rotors and it was ok.Already has new pads on it.Could there be a hard spot on one or both of the rotors or something in the master cylinder not right.It is not a ABS system.Thanks.
 
Hoople said:
What was [/I]the runout. OK to some might be a very high number.
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Hoople hits the nail on the head:D

On my 09 FLHR, the front rotor was a problem... Knowing the manager, they had to fudge on the warpage # to get it replaced UNDER warranty… Fudging was NOT wrong because as it Heated Up from use, it would get Worse...
Replaced with a stock one,,, no more problem.

Mine was Pulsing in the front handle,,, is where you could feel it First off, then it got worse as time and usage went by, yet, the pads and brake systems were good, never needed them replace then.

There are after markets that might be better than the stock HD ones but either way you go,,,,, I'd bet on the warpage:(

signed....BUBBIE
 
Harley allows up to .008 run out this is a huge number in run out, think about some car manufactures that allow only .003 HMMMM
 
I have heard that if the runout is not the problem, one cure for that elusive vibration, is to swap the rotors, left and right. Another is to go with Harley's own or aftermarket floating disc rotors...they are 2 piece...the spoke center held by floating rivets to the friction disc. This essentially "halves" the tolerance by allowing the fixed calipers to take up some of the runout, and the floating discs take up the rest.

Sportbikes I've owned in the past were equipped with these as standard for good reason. Braking was never a problem, calipers are always centered over the discs and the sound was a gentle p-u-r-r-r with no pulsing at the lever...EVER! Most disc brakes nowadays are "single action" meaning once you release the pressure, that runout is the ONLY thing to gently "nudge" the pistons into their bores so no excess drag to slow you down...worth a few tenths of a second, but every little bit helps! The even wear of the pads is evidence that it is working, or if you have one piece rotors the uneven wear will tell you they are NOT! :s
 
The runout was .004 sounds like the rotors are probably the problem.Thanks for all the input from everyone.
 
Had the same thing on my '99 Ultra. Bought two new rotors from J&P Cycles and the "pulsing" went away.
 
Just recently I replace stock rotors with Thunderstar floating rotors. I have a Thunderstar chrome wheel. With these new floating rotors the front brakes pulsed severly, i.e. really bad. So, we assumed new rotors might be warped. Put original stock rotor back on the right side -- still pulsed. Put floating rotor back on right side and put stock rotor back on left side. Still pulsed. Bottom line any combination using a floating rotor resulted in pulsing. Now have orginals back on and no pulsing. If you followed this scenerio, can any one explain -- other than both new floating rotors being warped. I'm sure HD dealer will not give me new floating rotors!

Thanks
 
bobbeidel said:
Just recently I replace stock rotors with Thunderstar floating rotors. I have a Thunderstar chrome wheel. With these new floating rotors the front brakes pulsed severly, i.e. really bad. So, we assumed new rotors might be warped. Put original stock rotor back on the right side -- still pulsed. Put floating rotor back on right side and put stock rotor back on left side. Still pulsed. Bottom line any combination using a floating rotor resulted in pulsing. Now have orginals back on and no pulsing. If you followed this scenerio, can any one explain -- other than both new floating rotors being warped. I'm sure HD dealer will not give me new floating rotors!

Thanks
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Turning the front wheel with a Dial Indicator will tell you the Trueness of the rotors... Best to do it with a good dial and make sure it is kept from moving on its own..

My bad one (rotor) was out enough to see when spun by a Good eye but the indicator tells all.....:s

signed....BUBBIE
 
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