Gomez

Okay, request permission to go off topic for a second here....

I've got a way to go before I reach nirvana, in spite of the change in gearbox oil I did recently, I still have issues with my shift quality. A lot of people have posted saying Red Line gearbox oil is a panacea to a myriad of gearbox problems....it's all bullsh1t. I don't rev to 8000 rpm, rarely above 6000, so I don't have the grinding issues into second a lot of others have.....but I continue to struggle at achieving the perfect first/second gearchange.

I'm not blaming the car, I just need more practice!

Gomez.

Pappy

I'm interested to know how I did this - can you please elaborate.

Since my first car in 1984 (a not too interesting Datsun Stanza with an awful dog-leg first manual gearbox), I've never had the experience of replacing discs (let alone for warpage).

Cheers,

Pappy

rpm_pwr

No problem.

In short it happens when more heat is built up than the braking system can get rid of. Most of the heat is lost through the disc and through the caliper via the pad. If the pads overheat, they can't transfer the heat away from this disc and it softens and warps. Tends to happens on powerful cars with street pads or just small brakes (eg XR6T/XR8). Small light, underpowered cars like your stanza just can't get themselves into that much trouble

I've heard you can do it by getting water on the discs when they are very hot but I've never seen it myself, though I have seen cracking from this.

lexic

Also tends to happen when there are manufacturing issues. Some batches of rotor can tend to be a little too soft. Manufacturers diliberately make the rotors as soft as possible so that more friction is created and you get better braking performance. If a batch is too soft then there is a fair chance of warping occurring.

Pappy

Funny you should say this - the dealer said the same that the discs probably warped after having water splash onto them when they were quite hot.

The hardest I've ever used the brakes was during the driver training course (provided by Mazda), and yes there was a thunderstorm at the end of the course -we actually didn't finish all the activities due to the lightening. That was about 10,000kms ago. If this caused the warping then Mazda shouldn't be giving us these courses and should issue some warning regarding hard braking and water.

BTW - there weren't any cracks on the discs - the dealer looked for this (as a sign of abuse).

rpm_pwr

Anyone else used the car? I just noticed you said the pads were squeeling as well. Which suck low k's I'd have to guess that the pads have been roasted too.

It seems pretty odd that they gave you new discs, since you can machine warped discs, but I guess they're erring on the safety side.

With the pad noise as well, I'd have to say if you didn't give the car a good thrashing recently then someone else has. Unless you drive with your foot on the brake

Pappy

The brake pads are apparently OK - don't drive the car hard at all and no else has driven the car apart from the Mazda mechanics.

Either the discs were faulty or extremely sensitive to temperature changes.

Pappy

Howdy,

I know this is an old post, but just an update for those that are interested.

Over the last month my brakes started shuddering again and today Mazda replaced both front disc rotors and brake pads under warranty.

I've only travelled about 6,000kms since replacing the disc rotors previously and Mazda AU suspect that not replacing the pads back then has caused the discs to warp again.

Anyway, the car is braking smoothly again and top marks for customer service to Mazda!

And no - I don't race my car nor drive it hard. Those 6,000kms were done going back & forth in the Eastern Suburbs during normal hectic Sydney traffic.

Cheers,

Pappy

sco

Thanks for the update.. welcome back.. it's been a while. Next thing, Dez will return.

timbo

That'd be the problem then. You need to drive it a bit harder -- seriously. There have been reports in the US of cars -- esp autos -- with a range of problemd due mainly to being used as daily commuters, and no redlines. C'mon Pappy --- cut loose in the baby (in a safe way, of course...am not suggesting you adopt street racing as a hobby....

dbb

I've got the same problem now. I'll get Mazda to look at it when I get the car serviced soon. However, at 40k km, I don't think they will be a warranty job. Any idea how much warped brake rotors will cost me?

Pappy

Not a problem sco - will try to increase my posts!

Thanks for the advice Timbo - Sydney traffic isn't always conducive to spirited driving, but maybe after the front pads have bedded in a little will fang it a bit!

dbb - no idea what the costs would be - but would 40k seem like a reasonable lifetime for the rotors?

timbo

rotors should last at least double that, unless you are a track day junkie

RXXX8

i think i'm experiencing warped rotors as well... you know that pulsating feeling when you hit the brakes.. does that occur when you're doing low speeds or high speeds? or is it always there? coz i was on the M4 the other day going around 160 or so and when u hit the brake, not like slamming the brakes i get the pulsating feeling as well..

also has anyone done any brake mods to their cars? coz i'm considering changing the pads.. any recommendations out there? are there any pads which may cause the stock discs to become warped?

Kas

hey all, i havent posted for quite some time.

my brakes pulsate when hitting the brakes at 100km or so. the car gets pretty jittery. I have 50k now and will be replacing brakes and machiening the rotors unless its a problem in the design?

any news of dealers replacing them ?

Pappy

Kas & WPNRX8,

My brakes shuddered/pulsated at both low and high speeds - the shuddering appears to be worse at high speeds but also quite evident at low speeds. At high speeds, applying the brakes felt like the car was going over tram lines - feels quite unstable.

Check with your Mazda dealer if they cover them under warranty.

My 2nd set of discs are braking smoothly for now - car has done about 19k.

Cheers,

Pappy

Kas

yeah will do pappy. my brakes are at the end of their life anyways so best to ask before replacing. If the rotors have warped then either way i'd imagine its a warranty issue.

LittleJohn

OK.. I'm going to chime in now.
I had pulsating brakes from about 27000ish kms and reported it when I went in for me 30000kms service. At the time Eurocars just machined the front rotors, which fro the large part worked well for about 3weeks then it started coming back.
I rang up last week and told them the pulsating was starting to come back and they told me to bring it back. Picked up my baby this arfternoon and all is well. It turns out they replaced the front rotors.
I monitor how it goes and will report back if the pulsating comes back.
On another note, while they were working on her, they checked the flash, as it turns out there was aparently a new flash which they received a few weeks ago.