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Makes And Models => Zero Motorcycles Forum | 2013+ => Topic started by: atldinan3 on July 17, 2020, 06:44:39 PM

Title: Greatly diminished rear braking power
Post by: atldinan3 on July 17, 2020, 06:44:39 PM
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Title: Re: Greatly diminished rear braking power
Post by: valnar on July 17, 2020, 07:23:27 PM
Is it a 2020 FXS?  My "rear master cylinder" was bad from the factory and had to be replaced.  I wonder if it was a production issue.
Title: Re: Greatly diminished rear braking power
Post by: atldinan3 on July 17, 2020, 07:28:10 PM
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Title: Re: Greatly diminished rear braking power
Post by: Richard230 on July 17, 2020, 08:30:19 PM
2017 DS

It worked fine for a while. Only recently did it start having problems.

First try cleaning the brake disc with contact cleaner or denatured alcohol. If that doesn't work, remove the brake pads and sand them a little on a piece of flat glass to remove any foreign substance that might be on them. If that doesn't work you might need to replace the brake pads.
Title: Re: Greatly diminished rear braking power
Post by: KuRi on July 18, 2020, 12:14:13 AM
Any noise or strange feeling when pressing the pedal?
Title: Re: Greatly diminished rear braking power
Post by: TheRan on July 18, 2020, 12:36:51 AM
Is there any improvement with ABS off (either turned off at the dash, fuse pulled, or with the bike keyed off)?
Title: Re: Greatly diminished rear braking power
Post by: Crissa on July 18, 2020, 03:27:46 AM
My S can't move if I stand on the brake pedal, so definitely something is wrong with the brakes ^-^

-Crissa
Title: Re: Greatly diminished rear braking power
Post by: atldinan3 on July 28, 2020, 01:54:17 AM
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Title: Re: Greatly diminished rear braking power
Post by: Curt on July 28, 2020, 02:22:30 AM
Do you generally rely on the rear brake instead of the front? Or do you tend to drag the rear brake for better control? If so, you may have worn it out.

Has your brake rotor worn too thin? It's easy to check if it's formed a deep groove along the outer edge. A new rotor is perfectly flat.

Have your brake pads worn down? It's easy to check if they are very thin or have worn away the wear indicator groove.

Otherwise, or in addition, it's time to replace the brake fluid and bleed the brakes. According to the manual, this should be done every year, but every 2 years is reasonable.

When you say your dealer is far away, do you mean your Zero dealer or any dealer? In fact, any motorcycle dealer service department should be able to service the brakes and rotor, especially if you have a Zero dealer mail you the replacement rotor/pads.
Title: Re: Greatly diminished rear braking power
Post by: DPsSRnSD on July 28, 2020, 03:24:53 AM
(Note that my closest dealer is out of range, and I don't have a trailer to get it there. So the standard suggestion to "take it to a dealer and have it checked out" is very difficult to accomplish..)

Almost any general automotive mechanic, regardless if they specialize in motorcycles, automobiles, or trucks, should be able to give you a hand with a brake problem.
Title: Re: Greatly diminished rear braking power
Post by: TheRan on July 28, 2020, 03:26:35 AM
Is there any improvement with ABS off (either turned off at the dash, fuse pulled, or with the bike keyed off)?
I've not tried turning off the ABS. I'm very hesitant to mess with the system like that. Is there any potential that I could do something that requires a trip to the dealer? (As I said earlier, closest dealer is out of range, and I don't have a trailer).
There's no real risk of damage with deactivating ABS, you don't even need to go fast to see if there's any improvement as you said that currently the brake will barely even bring you to a stop. It's not like you can even forget to turn it back on for when you next go for a ride as it resets when you key the bike off. It's also a very simple process, just key the bike on with the stand down and kill switch engaged, then hold the ADJ button on the dash together with the Mode button on the right next to the throttle for 4 seconds. The ABS light on the dash will flash about once a second when it's deactivated. Key off and back on again to reactivate it.
Title: Re: Greatly diminished rear braking power
Post by: Richard230 on July 28, 2020, 03:55:15 AM
Thanks, everyone, for the ideas.

Any noise or strange feeling when pressing the pedal?
I've not heard any noises or strange feelings. But I'll double check that this weekend.

Is there any improvement with ABS off (either turned off at the dash, fuse pulled, or with the bike keyed off)?
I've not tried turning off the ABS. I'm very hesitant to mess with the system like that. Is there any potential that I could do something that requires a trip to the dealer? (As I said earlier, closest dealer is out of range, and I don't have a trailer).

2017 DS

It worked fine for a while. Only recently did it start having problems.

First try cleaning the brake disc with contact cleaner or denatured alcohol. If that doesn't work, remove the brake pads and sand them a little on a piece of flat glass to remove any foreign substance that might be on them. If that doesn't work you might need to replace the brake pads.
I'll try the first two this weekend. I'm assuming the pads aren't bad, as they've barely got any miles.

It is possible that the brake pads glazed while the bike was being broken-in. Removing the pads and roughing them up with fine sandpaper on a piece of glass, or some other level service, might remove any glaze that had built up and restore their friction.