Troubleshooting help: crunching noise & sensation when pumping brakes with 2024 FL5

[josh_00]

Greetings,

I have a request for some advice & guidance with my issue. First here is a quick background:

Relatively recently (Sept 3rd or so) I brought my car into a dealership for some diagnostics with some mysterious minor clicking coming from both left & right front wheels when turning at low speed. They inspected the brakes and said it was due to a brake cotter pin so they made sure everything was properly aligned/seated and the noise seemed to go away.

Over September I drove ~200 miles and the clicking noise came back slightly but I wasn't concerned too much.

Now onto my current issue: this past weekend (Oct 4th or so) I noticed something strange when pumping the brakes - I was taking the car out of park with the e-brake and heard a crunching noise that I could feel in the pedal as well. This was after driving a fair bit on a 75 degree F day so there was some heat in the brakes at that point. I was concerned and brought the car back to the dealer service center the other day and they didn't seem too worried. One tech thought it could be potential air in the lines but I don't know, we both weren't sure. They reexamined the brake pad shims for the clicking noise, regreased them and aligned them again so the clicking noise is totally gone now but this "crunching" is still there when there's heat in the system.

I brought the car to a different Honda service garage and asked them to take a look. It was relatively cold (60 F) and I had to ask the tech to drive the car a bit to make sure there was heat in the brakes before the issue could be replicated. They confirmed there was some crunching noise & sensation in the pedal so they ordered a replacement part and I'll go back next week. I'm not exactly sure which part it is right now, the person scheduling the repair service mentioning something about a component behind the calipers but i'm not sure, i'll find out next week. I took a quick video when I got home earlier today when everything was still heat soaked; I parked the car and pumped the brakes from 50-100% a few times (I love that there's a bar graph display for this).

I asked one buddy and showed him this video, he thinks something might just not be aligned and perhaps not reassembled correctly from the initial repair back in Sept. That's plausible. Everything is covered under warranty so I'm not too worried, the car stops just fine at lower pressure and I've only ever braked at more than 50% in stuff like auto X so for just cruising around town the car is still drivable. Nevertheless, I am concerned and I want to at least know what could be causing this. At full brake pressure is something like 1500 PSI so I know it's quite a bit of pressure but this doesn't seem normal to me, i have no idea. When it's cold there is pretty much no crunching, it becomes much more prevalent as the parts heat soak.

I would greatly appreciate any help with troubleshooting this & potential explanations.

My car is a 2024 FL5 with ~ 4300 miles

 

[jtlctr]

Good move going to a different shop, it doesn’t sound like the first tech did a great job. Hard to say what the noise is without looking at it. Could be a loose caliper bolt. Maybe one of the caliper pistons is seizing and causing the brake pad to move crookedly. Hard to imagine that on a new car though. I would just drive with caution until it gets fixed.
please let us know what the issue is when it’s fixed.

 

[josh_00]

I have a small update (but unfortunately still no definitive cause of the problem).

The shop ordered these parts for the front right brakes:

• 46335 t60 a00 PIPE G, R, BRAKE
• 45018 tv8 e01 CALIPER SUB-ASSY
• 45019 tv8 e01 CALIPER SUB-ASSY

They got the parts in yesterday and I brought my car in earlier today for the repair. They replaced the front right brake calipers and the hydraulic hose/pipe, along with the bleeding the brake system, checking over everything, etc.

The crunching noise no longer emanates from the front right brakes when everything is up to temp and the brake pedal is pumped and/or pressed firmly. However, they only replaced the front right brakes so the issue remains on the front left brakes and there's still some feedback in the pedal, albeit slightly less than before so that's a start I suppose. They ordered the same components for the front lefts but apparently the parts are on back order so there's no estimate as to when the service center will get the delivery.

I'm glad that the issue is partially resolved but I'm also a bit confused as to why they only ordered one set of replacement parts when I tried to emphasize that the noise was coming from both front brakes. I didn't get a chance to speak with the techs when I picked up my car (I got there right at closing time). The service rep said something about how they couldn't be sure it was both components so they only ordered the one set but I was a bit baffled by their explanation so I just got the paperwork and left.

I hope the other parts they ordered show up soon because it seems that replacing the caliper sub assembly and hydraulic hose resolves the issue. Nevertheless, I am still left wondering what caused this problem in the first place.

For full disclosure: I don't know if this would affect anything but I have aftermarket Mugen forged rims (which are the same dimension as the stock rims) with the Michelin summer tires the car came with, I consider this OEM+ because it's the same offset and everything as the stock set up. The wheels are significantly lighter but that's it I think. I don't know how this would affect the brakes. I got the new wheels back in May of this year and only started to notice this crunching issue recently so I doubt the wheels are the cause but I have no idea.

Everything is being covered under warranty and since it's Fall, the weather is relatively cool so it still takes a bit of driving to even get the brakes hot enough for the problem to become apparent which means I can at least drive my car a little. I wanted to go to another auto cross or two before the season comes to close but I suppose I'll wait until next year if I can't get the brakes in order before the last event. I could probably get away with going to a few more auto cross sessions but I'll just err on the side of caution for now.

 

[jtlctr]

It is highly unlikely that both calipers would simultaneously have an issue like this, especially on a new car. Are you absolutely sure the noise was coming from both sides before? Is it possible that they just replaced the wrong side? Was there some hard braking events (like autox) that preceded the issues? Does the pedal feel softer than before? I’m wondering if maybe the fluid boiled and introduced air into the system which may account for both sides exhibiting the same symptoms. It might be worth trying to bleed the left caliper. Otherwise, I guess you’ll have to wait and see what happens after the second caliper replacement.

 

[josh_00]

That is a good point that I neglected to mention. I have been regularly going to auto x events since I got my car last year.

The most recent auto x I went to was mid summer at an old airstrip so it was essentially an out and back with a big turn around point halfway; there was a hard braking zone at that turn around point. And I think it was maybe 5 laps total around 50 seconds each lap. From memory I wasn't hard on the brakes for my first few sets until I learned the course a bit, so maybe there were 3 or 4 laps where I was hard on the brakes for one part of the course.

Would an event like that really be enough to boil the brake fluid? I didn't notice anything weird with the brake pedal at the time. It seemed fine on the drive home. There was only the one braking zone and the rest of the course was made up of regular slalom elements. This was back in late July. However, this was when I started to notice a clicking noise come from both front wheels which was why I brought my car in to the other Honda shop back in September. The course had been particularly dusty & gravelly so I thought it was debris at first.

I know track days have a good chance of cooking the brakes but I have yet to go to a full track event, so far I've only gone to auto x.

I've had some discussions about brake fade with other drivers at auto x because braking hard is something that I still struggle with doing properly. Losing brakes is something that I want to experience so I can learn how to manage the car when it happens. But usually when I talk to people about it they say it happens on full road courses. I'm sure it can happen in auto x too so idk. Normally I'll be leaving time on the table because I'm slower on entry into corners and I won't have to brake as hard if I was utilizing more potential of the vehicle (this is the fastest car I've ever had so I'm still working on getting more comfortable with really trying to go quick).

After the auto x back in July I only noticed a slight clicking coming from the front wheels, there wasn't any crunching sensation or noise that I noticed until I got the car back from the garage in September/October. I wish I could get a concrete cause of the issue.

Today the brake pressure seems about the same as before (at least driving home), I'll check more closely tomorrow.

In any case, I have to go back to the Honda garage in a few weeks when it gets cold to put on the stock wheels with winter tires and get an oil change so I can ask them if they can check again and bleed the left front brakes to see if there's any air trapped in the system. I am also wondering if this was something that could've been fixed rather than outright replacing the components.

And I'm pretty sure the noise was coming from both front brakes. When I first noticed it a few weeks ago I asked my dad to sit in the driver's seat and pump the brakes as I walked around the car to listen to the crunching noise

 

[jtlctr]

I wouldn’t think auto X racing would create a situation that got the brakes hot enough to boil the fluid, but I don’t have any racing experience, so I’m not sure. I understand that the brake pedal basically goes to the floor if the fluid boils though, so I’m sure you would have noticed.
I will be curious to hear what happens after they replace the other caliper!

 

[josh_00]

I'll post what is hopefully a final update for my issue.

Yesterday I got my car back from the Honda garage after they replaced the front left brake caliper and hardline. This seems to have completely resolved the crunching/creaking when pressing the brakes hard so I'm glad it's finally fixed.

When I tried asking about the root cause of the problem with the service advisor they said it was hard to say. They'll send the original parts back to Honda corporate for analysis but that will be the end of the process for the local service center so I wonder if just got unlucky with some faulty components from the factory or something thereabouts. Regardless, I'm glad this was all covered under warranty.

I won't go to another motorsport event until next season because I just put on my winter wheels but after driving around a little bit today at around 60 degrees F the brakes felt fine. Hopefully this problem is gone for good, I'll find out for sure next Spring when I put the summer tires back on and go to an auto X.

 

[jtlctr]

Nice, man! I’m glad it all seems resolved. Too bad there wasn’t a full explanation, but at least it was free. In any case, I’m sure it was nothing you did wrong, just a faulty something or other!
Thanks for the update!

 

[phononmode]

I am having the exact same issue. Wonder if anyone else experienced it and knows the root cause.