Vibration during turn-in

[EPSi2FKR]

Hey y’all,

Thanks for your time. So, the brakes seem to be giving me a problem. Two events ago, I had some brake shutter so bad, it felt like wheel hop. I felt it mostly on hard braking and some on turn in. I tried to power through it like it was a bedding/surfacing thing but no dice. Tripped a bunch of sensors and scrapped the session.

So, got all new pads and rotor rings. Went out again. It was better but still had some issues. The video is from this event. This time, the shuttering and pulsing are more at turn in. All the buzzing you hear (sounds like diving on rumble strips) and the shaking with it is the problem. It’s unbalancing the car. There was a little on hard braking (0:33) but that seemed to sort out. Most of the symptoms are on lap 2-3 of a cold 25 minute session. And once the car warmed up and at speed you can barely notice it (1:00). But by the end of that session of really getting on it, I had brake fade! I stopped the event there. Did a bleed after and fluid was indeed brown.

Some extra info. Both these events were cold. Im stilling getting better with braking but far from good. I’m going through pads in 2-4 track days, which seems excessive. This car is generally hard on brakes but not this much. It’s a weird issue. The car is at the performance shop now and They said the hubs and axels are fine. Just seeing if y’all have any ideas.

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[86salmon]

Normally I'd say check rotor wear, but you changed them. Are your sway bars and control arms tight?

 

[REDRAGN]

What pads are you running? Its possible the temp range of the pads is so far out in the cold conditions that it is causing your issues

 

[EPSi2FKR]

What pads are you running? Its possible the temp range of the pads is so far out in the cold conditions that it is causing your issues

Paragon R7s. I was thinking of scaling back to R5s but they weren’t lasting more than 4track days.

 

[Romeoridgee]

Check the rears, did you install the wunderladden racing rear caliper bushings?

 

[EPSi2FKR]

The rears have new rotors and pads as well. After a test drive, my performance shop was asking about the rears. I did not install those bushing, first time I’ve heard of them.

 

[Romeoridgee]

https://www.wunderladenracing.com/products/civic-x-rear-caliper-bushings

 

[Brandondan1]

You might want to check your front caliper metal pad retainer clips. They can become uncentered/lodged to one side, if you aren't careful when tapping the pins back in. This can put extra pressure on pad(making it essentially drag constantly) and cause accelerated wear/heat buildup.

If you're wearing out pads quickly you might notice more discoloration/ paint turning brown from heat buildup. Excess heat can damage your caliper seals, so might make sure your pistons aren't leaking/seized.

With the agile handling assist, the car will brake vector on turn-in, braking the inside front etc. I'm wondering if that system is initiating the behavior with your brakes while you're not actually using them.

Lastly, check your front bushings for wear, and do a torque check on your suspension/brake components.

 

[EPSi2FKR]

With the agile handling assist, the car will brake vector on turn-in, braking the inside front etc. I'm wondering if that system is initiating the behavior with your brakes while you're not actually using them.

2 sessions ago the right front inner pads wore WAY faster than the other 3. I do traction control fully off (5 second button hold) on the track. Would the agile handling assist still be active that way? Does it affect you? Is there any way to disable it? Thanks for your time.

 

[REDRAGN]

Paragon R7s. I was thinking of scaling back to R5s but they weren’t lasting more than 4track days.

I literally just switched to R7 and haven't gotten them on track yet...my R5 did wear fast but that's partially due to the type of use (high speed tracks) but did think the R5 were solid pads.

Do you have any of your old R5 to just swap back in and see if the problem stops?

 

[Brandondan1]

2 sessions ago the right front inner pads wore WAY faster than the other 3. I do traction control fully off (5 second button hold) on the track. Would the agile handling assist still be active that way? Does it affect you? Is there any way to disable it? Thanks for your time.

I believe AHA is active even with tcs "fully off" (but less intrusive with using the rear brakes to keep the car stable.. and allows more slip angle) I think pedal dance is the only way to turn it off fully. I'm not saying AHA is the problem, just trying to think of why it happens on hard braking AND still on turn-in when you've released the brakes.

The fact that only your front right inner pad wore way faster, shouldn't be happening. Sounds like it's dragging. I'd check that caliper, piston seals, pad bracket. Did you get air bubbles the first time you bled it? Is your layer of pad transfer on your rotors even, or are there splotches? You've replaced the rotor rings so you can rule out warping at least.

If you can replicate it on the street safely, you can rule out things easy things one by one. Try putting on stock wheels if theyre balanced (sometimes track wheel weights fall off from heat). Try stock pads up front like mentioned above, that you know shouldnt have issues.

It could be a loose bolt, or worn bushing/ball joint related, if it's allowing enough slop/play under load to cause that much vibration.

When you mentioned feel of "wheel hop" I thought about engine mounts and RMM.. Although that occurs under power, if you're getting that much vibration under braking/lateral load, sometime might be failing/wearing out.

Hard to say without seeing the car, but reduce variables to narrow it down. Good luck!

 

[Dave B]

R7s are aggressive pads and are likely at least part of your issue when cold. You might also have a sticky piston which you can checkout easily on the street

 

[EPSi2FKR]

R7s are aggressive pads and are likely at least part of your issue when cold. You might also have a sticky piston which you can checkout easily on the street

The car just got a clean bill of health after 3 days at the performance shop. Calipers were rebuilt earlier this year with all Honda parts and the pistons were pristine.

Yeah, that’s the plan for now. I’m switching back to R5s first. If the problem persists, I’ll try the pedal dance to see if the AHA or other nanny is the culprit.

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