Rear Brake seems to be Hunting

[Fjrwillie]

Been out of commission for most of the summer. Took the bike out for an up and down the street. When at a stop, it sounds like the rear brake is hunting, not constantly .

Any thoughts

Willie

[chipveres]

I don't understand the problem. Never heard of a brake hunting before. Could you please explain?

[Isopedella]

I too have no idea what hunting is - please expand or describe.

Have you had a look at anything at all?

Like ....Taken the caliper off, checked the pads, pucks ?

[BajaRon]

I wonder if he isn't speaking of surging, like with a warped rotor. Or maybe the wobble that the VSS can give you in turns.

In any case. A hunting rear brake (or any brake for that matter) is a new one on me.

[KAMJAM]

I'm been feeling a surge when coming to a stop on my 2020 RT w/6,500 miles on the clock. We had similar situation with the front rotors of one our other vehicles shortly after have a brake job, which included cutting the rotors down a bit. It started immediately after panic stop, but I've never had to stomp on the brake pedal of my RT, yet.
This weekend I am going to pull the front wheels and use a dial indicator on the rotors, maybe pull the caliper on the rear and get the rear wheel off the ground to check the rear.

[Fjrwillie]

Been out of commission for most of the summer. Took the bike out for an up and down the street. When at a stop, it sounds like the rear brake is hunting, not constantly .

Any thoughts

Willie

Hunting It is a sound

Hunting. It is a sound of movement coming from the rear, my guess the brake. Sounds like the electronic brake trying to seek a position. So hunting would be the piston in the calipher moving in and out.

Willie

[BertRemington]

Two possibilities:

1: You parked your Spyder with hot brakes and set the parking brake. This can leave a "hot spot" on the rotor that has different friction characteristics than the rest of the rotor, which will result in a pulsing feeling when the brakes are applied.

2: You parked your Spyder in an environment exposing the rear rotor to salt air, which leaves a "clean spot" on the rotor that has different friction characteristics than the rest of the rusty rotor, which will result in a pulsing feeling when the brakes are applied.

Ignore the above: I misread "When at a stop" as "When stopping". Apologies.

[Little Blue]

Hunting for a brake job and fluid change. If you have not changed your brake fluid this could be a good starting point.
The brake fluid needs to changed every 2 years.

Just a quick thought. ....

[Snowbelt Spyder]

Hunting It is a sound

Hunting. It is a sound of movement coming from the rear, my guess the brake. Sounds like the electronic brake trying to seek a position. So hunting would be the piston in the calipher moving in and out.

Willie

Well, for one thing Willie, it’s not an electronic brake. It’s a hydraulic brake. And you said you were stopped when you heard this. Then it’s not a rotational issue, either. I’d say it was your air compressor and rear air suspension system stabilizing after the stop.

[Fjrwillie]

Well, for one thing Willie, it’s not an electronic brake. It’s a hydraulic brake. And you said you were stopped when you heard this. Then it’s not a rotational issue, either. I’d say it was your air compressor and rear air suspension system stabilizing after the stop.

Thanks I kind of eliminated the rear air, because I haven't felt the bike rising or lowering. If it stabilization which would not move the rear suspension up or down then this might make sense.

Willie

[Snowbelt Spyder]

It’s kinda like this. You put on the brakes to come to a stop. Like any vehicle, the nose of the Spyder dips down. The rear rises, the sensor tells the computer that the suspension is too high, and the computer lets out a little air. You won’t hear it.

After you stop, the suspension settles back to level, and because some air was let out, the sensor tells the computer that now, the suspension is too low. The computer runs the compressor for a second or two to put the air back in. You hear a second or two of Brrrrrrr. You won’t feel anything raising up or down. This operation happens over and over all day long as you ride around.

That’s what I meant by stabilizing. Bottom line, it’s not the brake.

[Flamewinger]

I'm been feeling a surge when coming to a stop on my 2020 RT w/6,500 miles on the clock. We had similar situation with the front rotors of one our other vehicles shortly after have a brake job, which included cutting the rotors down a bit. It started immediately after panic stop, but I've never had to stomp on the brake pedal of my RT, yet.
This weekend I am going to pull the front wheels and use a dial indicator on the rotors, maybe pull the caliper on the rear and get the rear wheel off the ground to check the rear.

With only 6500 miles you shouldn’t have any problems with the pads or rotors. The fluid should be flushed every 2 years. Ride it more and service it when required.

I have over 10k on my ‘21 F3 and the brakes are still practically new.

[BLUEKNIGHT911]

It’s kinda like this. You put on the brakes to come to a stop. Like any vehicle, the nose of the Spyder dips down. The rear rises, the sensor tells the computer that the suspension is too high, and the computer lets out a little air. You won’t hear it.

After you stop, the suspension settles back to level, and because some air was let out, the sensor tells the computer that now, the suspension is too low. The computer runs the compressor for a second or two to put the air back in. You hear a second or two of Brrrrrrr. You won’t feel anything raising up or down. This operation happens over and over all day long as you ride around.

That’s what I meant by stabilizing. Bottom line, it’s not the brake.

And ...IMHO ... this is the reason that the compressor wears out quicker than most folks thinks it should .... Folks here have had better results after changing to the VAIR compressor .... good luck ... Mike

[BajaRon]

Thanks I kind of eliminated the rear air, because I haven't felt the bike rising or lowering. If it stabilization which would not move the rear suspension up or down then this might make sense.

Willie

My feeling is that you should revisit the air ride system. An known issue point. It is not possible for the rear brake system to generate the sounds you describe. Or any sounds at all at rest.

[Snowbelt Spyder]

And ...IMHO ... this is the reason that the compressor wears out quicker than most folks thinks it should .... Folks here have had better results after changing to the VAIR compressor .... good luck ... Mike

My feeling is that you should revisit the air ride system. A known issue point. It is not possible for the rear brake system to generate the sounds you describe. Or any sounds at all at rest.

Yep and Yep. And calibrating the air ride system, per the manual with those two “special tools” - which are just two blocks of wood cut to specified length - cuts down on a lot of that. Been there. But unless you have BUDS and do it yourself, most didn't come correctly calibrated from the factory. I don’t know about the 20+ models yet. A dealer would probably charge for two hours to do it.

[Fjrwillie]

It’s kinda like this. You put on the brakes to come to a stop. Like any vehicle, the nose of the Spyder dips down. The rear rises, the sensor tells the computer that the suspension is too high, and the computer lets out a little air. You won’t hear it.

After you stop, the suspension settles back to level, and because some air was let out, the sensor tells the computer that now, the suspension is too low. The computer runs the compressor for a second or two to put the air back in. You hear a second or two of Brrrrrrr. You won’t feel anything raising up or down. This operation happens over and over all day long as you ride around.

That’s what I meant by stabilizing. Bottom line, it’s not the brake.

Thanks for the further details and explanation. It all makes sense.

Willie

[KAMJAM]

With only 6500 miles you shouldn’t have any problems with the pads or rotors. The fluid should be flushed every 2 years. Ride it more and service it when required.

I have over 10k on my ‘21 F3 and the brakes are still practically new.

Thanks for responding. I agree, we should not be having any issues with the brakes with less than 7k miles.
Things have gotten significantly worse in a very short period of time, the pulsing has increased and the right fender shakes violently while braking. I have decided stop riding the RT until I replace the the front rotors and pads with EBC components, hopefully this will take care of the issue prior to our upcoming vacation. I could attempt a warranty replacement , but we still work full time+ and our free time is extremely valuable/limited and I don't want to spend it fighting with manufactures at this time over issues like this. The down time with dealer visits significantly reduces our "ride time" as riding is our primary recreational activity.

It will cost me less than $300 and hopefully fix a problem that will not be happen again. Fingers crossed.

Ken

[KAMJAM]

Update, I replaced all rotors and pads, still experienced the "pulsing/surging" when coming to a stop, my wife's RT does not have this issue. I am taking it to the local dealer to resolve the issue. I think the issue is related to the ABS.