Author Topic: Rear Brake Issue  (Read 1089 times)

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Offline Cwaig

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Rear Brake Issue
on: September 17, 2021, 10.16 AM
Has anyone had any issues with their rear brake? I'm finding that if I used mine it grabs and lets go as the wheel rotates, plus makes an unpleasant squeal sound. It's usually ok until it warms up a bit.

Assumed it was just new pads+disks bedding in when I got it, but it's still bad at 1300miles.
Dealer insisted they couldn't feel a problem on test ride at first service - but I can feel the vibration from it as is snatches at the disk right through the bike.

If it was a car, I'd be thinking warped disk (our old Alfa Romeo had a warped disk in the first 500 miles). Never had a feeling like it on a bike though.



#1

Offline tridentmania

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Re: Rear Brake Issue
Reply #1 on: September 17, 2021, 10.46 AM
All okay with mine  :027:
From '61>present - '57 BSA C12, '61 RE C/Sports, '59 Tiger 110, '61 T120R, '57 BMW R50, '76 GT185, '69 T120, KE 175, BMW R75, GSX750, FJ1200, XJR1300, FZ1000, '05 Sprint1050 & '08 Street Triple, Sprint1050, Speedtriple, Sprint1050, SprintGT, Trophy 1215, Speedtriple & '12 Bonne, '15 XRx,'18 XRt, Trident 660

#2

Offline slf

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Re: Rear Brake Issue
Reply #2 on: September 17, 2021, 04.57 PM
*Originally Posted by Cwaig [+]
Assumed it was just new pads+disks bedding in when I got it, but it's still bad at 1300miles.

Have you tried disabling ABS and doing some bedding stops?
Last Edit: September 17, 2021, 04.57 PM by slf

#3

Offline 3Teeth660

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Re: Rear Brake Issue
Reply #3 on: September 17, 2021, 09.02 PM
You can get a rust spot on the disk if the bike is put away wet (from rain or cleaning).  This can cause a pulse in the pedal and felt through the bike until the rust wears off.  Had this happen on the front disks of my KTM and some hard braking eventually sorted it.  It's common on car rear disks when the handbrake is on, the wet pads rusting onto the disk.

If the disk is warped, you'd be able to see it if you can get the bike up on a stand and give the rear wheel a spin.  It's also got a single piston sliding caliper so worth checking it does slide correctly.

#4

Offline Cwaig

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Re: Rear Brake Issue
Reply #4 on: September 22, 2021, 12.13 PM
No rust spots (only been ridden on dry days - me=="fair weather biker"  :164:).

Nothing visible on the surface, so I borrowed a run-out gauge kit off a friend... disc has a runout of 0.5mm (inner edge) to 0.6mm (outer edge). That seems like a lot to me (0.019" to 0.023" for the metricly challenged).

Think I'll ring the dealer on this one...

#5

Offline 3Teeth660

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Re: Rear Brake Issue
Reply #5 on: September 22, 2021, 03.24 PM
Yeah, that's not right is it?  Must have been put on bent.

#6

Offline Cwaig

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Re: Rear Brake Issue
Reply #6 on: September 22, 2021, 03.48 PM
I swung by the local (well, 14 miles away) dealership at lunchtime - they're putting through a warranty replacement on it  :002:

#7

Offline Rchrd

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Re: Rear Brake Issue
Reply #7 on: September 30, 2021, 04.28 PM
I have a somewhat similar thing with my rear brake.... I can suddenly "feel" the rear brake through the brake lever at very low speeds (like creeping, about to stop at a light etc) when rear-braking now, the bike is at ~6400 miles and this started maybe a couple few hundred miles ago. It feels like a pulsing through the lever. The brake rotor has weird spots on it too but it does not appear to be warped. The bike did get wet one day because my idiot roommate was watering plants in the front and blasted the bike like a moron. Maybe its rust?
Rchrd

Whatever you do, don't steal.

#8

Offline Cwaig

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Re: Rear Brake Issue
Reply #8 on: October 15, 2021, 08.29 AM
Quick update - disk & pads replaced under warranty a couple of days ago. Not had a chance to really try it out properly yet though.

Dealer loaned me a Street Twin for the day while the work was done - very different bike, but have to say the Brembo’s on the Twin are vastly better than the Trident (so was the gear shift and suspension).

#9

Offline Cwaig

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Re: Rear Brake Issue
Reply #9 on: October 20, 2021, 10.37 AM
Finally managed to get the bike out for a lunchtime around-town test run yesterday. The replacement disc has totally sorted the problem :)

 



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