Front Disc Grooves, TSB, Replacement? - Mazda CX3 Forum
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post #1 of 10 Old 03-05-2018, 11:31 PM Thread Starter
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Front Disc Grooves, TSB, Replacement?

The first month of ownership, I questioned/complained about deep grooves in the front discs and received yet-another-intelligence-insulting excuse/explanation.

In the meantime it turns out Mazda (North America) has issued TSB 04-002/17 "If groove damage is found on a disc plate (A) and brake pad (B), replace the front brake pads with a modified service set and ONLY the damaged disc plate(s)."

Has anyone had this done?

P.S. I've found Honda dealers to be no less defensive than Mazda ;-)

2017 CX-3 GT, AWD, i-ActiveSense, Ceramic Metallic, Black ... His: Zoom, Zoom!
2016 HR-V EX-L, AWD, Milano Red, Black ... Hers: Putt, Putt.

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post #2 of 10 Old 03-06-2018, 06:41 AM
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Grooves on discs rarely cause a problem as far as braking efficiency is concerned. However, it causes the vehicle manufacturers a problem because according to their own standards, grooved discs should be replaced at routine inspection.

Ordinary grey cast iron does some funny things when quenched with cold water from a normal operating temperature of say 400-500F. It tends to shed small flakes of metal that embed themselves in the pads. At Ferodo we called it “metal pick up” and most of the German manufacturers called it “fish” because they were fish shaped! These little hard bits could groove the disc but as stated before, it doesn’t effect braking. In fact you could half the area of the pad widthways and the brake performance wouldn’t be affected at all as friction is independent of area.

I’ve got a similar bulletin for Europe which puts it down to “certain de-icers” that are used to treat roads. I suspect that is an interpretation of what the supplier of the pad (Textar) has told them as they are well aware of what causes it. Most countries use rock salt to treat roads but others are now using magnesium phosphate (white crystals that ironically look like crushed ice) which are very good at melting ice but is known to lower friction. Neither of these materials put grooves in discs, it is merely quenching that does it.

What to do about it? Well if you can arm yourself with a copy, go and dig in and tell them it doesn’t meet their own inspection standards so you want new parts. If they try to do one side, dig in again and say that you wouldn’t be able to convince them to do it if you were paying because that is mal practice too. It says modified parts and they might be slightly different but under the same conditions they’ll probably do it again to some degree but you will get new parts out of it. In reality, unless the discs have reached the thickness wear limit, if you can’t get them to do it, you won’t notice any reduction in brake performance. Big it up a bit and tell them they squeal when cold and your local garage has told you it’s no good etc, etc but try and get a copy of that TSB. I’ll attach the European one just for a read.
Attached Files
File Type: pdf Brake Grinding Noise from Front Brake.pdf (246.9 KB, 223 views)

Currently CX5 SportNav 2.2 diesel automatic and AWD.
Formerly CX3 SportNav 1.5 diesel automatic and AWD.

All advice is given in good spirit and taken entirely at the readers own risk. WORK SAFELY. ©2018 anchorman

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post #3 of 10 Old 03-06-2018, 06:34 PM Thread Starter
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Thank you Anchorman! Yes, I printed out the TSB. The Anchorman is spot on as always, the actual braking performance seems unaffected ... it just looks bad, especially when her HR-V's discs are all smooth as a baby's butt.

P.S. Speaking of "spot on" ... now only a faint memory, 1955 or '56 Sebring, Mike Hawthorn piloting a D-Type, screaming down the back straight, piling on the brakes (binders), the discs glowing red hot in the night ... as I recall, they were called "spot brakes" back then.

2017 CX-3 GT, AWD, i-ActiveSense, Ceramic Metallic, Black ... His: Zoom, Zoom!
2016 HR-V EX-L, AWD, Milano Red, Black ... Hers: Putt, Putt.

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post #4 of 10 Old 03-06-2018, 08:44 PM
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Quote:
Originally Posted by mainemanx View Post
Thank you Anchorman! Yes, I printed out the TSB. The Anchorman is spot on as always, the actual braking performance seems unaffected ... it just looks bad, especially when her HR-V's discs are all smooth as a baby's butt.

P.S. Speaking of "spot on" ... now only a faint memory, 1955 or '56 Sebring, Mike Hawthorn piloting a D-Type, screaming down the back straight, piling on the brakes (binders), the discs glowing red hot in the night ... as I recall, they were called "spot brakes" back then.
I don’t think I’ve heard the term but we regularly got them glowing during testing. The amazing these days is that it’s virtually impossible to boil the fluid.

Currently CX5 SportNav 2.2 diesel automatic and AWD.
Formerly CX3 SportNav 1.5 diesel automatic and AWD.

All advice is given in good spirit and taken entirely at the readers own risk. WORK SAFELY. ©2018 anchorman

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post #5 of 10 Old 03-07-2018, 04:06 PM Thread Starter
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I don’t think I’ve heard the term but we regularly got them glowing during testing. The amazing these days is that it’s virtually impossible to boil the fluid.
Interesting Wikipedia article on disc brakes. Late 50s they may have been called "spot brakes" by my faithfully-subscribed Autocar, The Motor, or R&T :-)

P.S. "Those were the days", when we bled the bakes after topping off for fluid loss.
I understand the Japanese driving test still requires you to "pump the brakes"

2017 CX-3 GT, AWD, i-ActiveSense, Ceramic Metallic, Black ... His: Zoom, Zoom!
2016 HR-V EX-L, AWD, Milano Red, Black ... Hers: Putt, Putt.
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post #6 of 10 Old 03-21-2018, 04:42 PM Thread Starter
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Took my groovy discs into the dealer this morning ... after a few minutes listening to the lady advisor "it's normal wear, never seen that before, etc." ... a senior service advisor with whom I'd previously dealt came over, glanced at the TSB, and instructed, "order the parts ... we'll call him when they come in".

Upon commenting my wife's HR-V's discs were silky smooth, the senior advisor opined the HR-V "is an appliance ... your CX-3 is a lot more fun". At least his heart is in the right place :--)

2017 CX-3 GT, AWD, i-ActiveSense, Ceramic Metallic, Black ... His: Zoom, Zoom!
2016 HR-V EX-L, AWD, Milano Red, Black ... Hers: Putt, Putt.
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post #7 of 10 Old 08-25-2018, 01:27 AM Thread Starter
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After 5 1/2 months of misunderstandings, miscommunications, frustrations, and maybe a dash of incompetence, as of today, I now have bright, smooth, new rotors and pads.

Gratis ... Arrigato Shachou Matsuda-san!

2017 CX-3 GT, AWD, i-ActiveSense, Ceramic Metallic, Black ... His: Zoom, Zoom!
2016 HR-V EX-L, AWD, Milano Red, Black ... Hers: Putt, Putt.
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post #8 of 10 Old 08-25-2018, 04:39 PM Thread Starter
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Ha! The fish are gone ... I should have asked to see the old pads.

Also, I should have clarified, only front brakes were done ... the rears are still rather groovy. But from what I understand, the front's provide up to 80% of the actual braking.

2017 CX-3 GT, AWD, i-ActiveSense, Ceramic Metallic, Black ... His: Zoom, Zoom!
2016 HR-V EX-L, AWD, Milano Red, Black ... Hers: Putt, Putt.
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post #9 of 10 Old 08-30-2018, 06:11 AM
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The fish might come back in winter but they tend not to affect the braking. They come and go!

Currently CX5 SportNav 2.2 diesel automatic and AWD.
Formerly CX3 SportNav 1.5 diesel automatic and AWD.

All advice is given in good spirit and taken entirely at the readers own risk. WORK SAFELY. ©2018 anchorman

“.........and another thing"
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post #10 of 10 Old 08-31-2018, 12:17 AM Thread Starter
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The fish might come back in winter but they tend not to affect the braking. They come and go!
Oh No! Stay away little fishes ... sufficient numbers are already enjoying the rear pads and the groovy, groovy rear discs.
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2017 CX-3 GT, AWD, i-ActiveSense, Ceramic Metallic, Black ... His: Zoom, Zoom!
2016 HR-V EX-L, AWD, Milano Red, Black ... Hers: Putt, Putt.

Last edited by mainemanx; 08-31-2018 at 10:19 AM.
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