LiveWire

iTrader: (1)

When I say new brakes, I mean I put new pads and rotors on myself. Everything was good and dandy until that near accident. I'm not claiming to know exactly what caused the grooving, but something certainly did. After that I took my car to the dealer because there was no way I was replacing rotors again that soon. All they did was resurface the front rotors and change rear diff fluid. That's it.

Pads and rotors were stoptech (full face rotor). When my car sits outside overnight, it tends to have a surface rust layer on the rotors. Maybe that was not cleared off completely after 5 minutes of driving and caused the grooves? I have no idea. Regardless, I don't think I ever said anything about the pads being worn... It will be interesting to see what they look like.

Also on the track, I'm pretty sure you don't lock up your wheels on your routine passes. If the problem was braking too hard I am sure the rotors probably would have warped.

40w8

Ok, so 5k miles ago you put on Stoptech rotors and pads, and now the rotors are grooved and heat spotted.

Locking up wheels won't do it, and that thin film of rust from sitting won't do it.

It takes repeated heat over a period of time which is apparently 5k miles, and way too soon.

I found the original brake pads and rotor to be fine, even with my medium hard track use.

Track day would be like missing that accident 300 times in a day, and my rotors are in very good smooth shape at 9 years and 33k miles.

You just reviewed Stoptech rotors which tells me to stay stock.

Steve Dallas

The parts you used should not have caused that. I have used StopTech rotors and brake lines many times and always found them to be high quality. There are 2 sets of StopTech rotors on my parts shelf right now. I have never used their pads, but reviews of them are mostly positive. Negative comments are typically that they wear more quickly than other options and produce more dust than people like. Nothing major.

I'd have to see a photo of your rotors to know what you mean by "grooves" and "heat spots". It's possible a hard bit of rock embedded itself into one or more of those softer pads when it was hot. Otherwise, StopTech pads are not reported to be hard on rotors.

Surface rust on rotors is perfectly normal and harmless. The pads will scrape it off quickly to no effect. In fact, rust bad enough to cause pitting is harmless. The pads will scrape off the surface rust and glide over the pits.

Locking up a set of brakes is actually easier on them, because they stop building up heat as soon as they are locked. It's the tires that take the real punishment under lock-up.

Rotor warping is largely a myth. Mechanics like to talk about it, and they are convinced it exists, because turning the rotors will make it "go away," but what they are usually doing is scraping off uneven friction material, which causes the illusion of warped rotors. It is actually very hard to warp a rotor, as it requires extreme heat and uneven pressure--both much higher than the vast majority of cars ever see.

That event alone did not wreck your brakes. Something else was amiss and causing damage. That event could have punctuated or exposed the problem, I suppose.

What I think 40W is trying to convey in terse language is this. A typical track day for me is at least 72 laps. My home track has 11 turns. That means I am on the brakes HARD 11 times per lap. Three of those turns see me slowing from 110 to 120mph down to 50 to 65mph under VERY HARD braking. (Slowing from 120mph to 60mph is much harder on the brakes than slowing from 60mph to 0mph, even though the net reduction in speed is the same). So, I do something like your scenario at least 792 times per track day. Two hundred sixteen of those braking events are brutal. I do that up to 18 times per year, which adds up to 14,256 total hard braking events, of which 3,888 are very hard braking events. When I leave the track, my rotor temps are over 1,000F. I do all that without grooving rotors or creating heat spots. A set of front rotors (sometimes StopTech) lasts me at least 2 years and 6 sets of front pads.

In summary, the event couldn't have done it, and the parts likely did not do it. It had to have been something else, like dragging pads due to installation error, pesky rocks embedding in pads, improper bleeding, or lack of caliper retraction by another cause.

I have one other thought. You mentioned removing the rear sway bar, and having that cause you to spin. All things being equal, removing the rear bar should cause terminal understeer, which should cause the car to push, not spin. Strange.
.

40w8

Some early caliper designs of the 70's on Ford F150's and Toyota's that I had, would make them run tight, and I've had grooves.

My 73 RX3 would heat spot a little at 50k miles, but not wear pads, and caliper ran loose.

I should have stayed with stock pads, and all pads after that wore out in like 10k miles.

I learned to be careful about "fixing stuff"; "if it ain't broke don't fix it".

LiveWire

iTrader: (1)

I mentioned that the pads and rotors were stop tech to provide more information of the setting, not to bash, nor to review. I can't tell you what the products can or cannot handle and I do realize that plenty of people put the same product through repeated harsh conditions. However what I can tell you is the condition they were in before and shortly after this event.

Prior to this event I had been periodically visually inspecting the rotors, there was no apparent damage. I felt no problem with the brake pedal. I highly doubt there was an installation error either - changing rotors and pads is simple task and I made sure the faces of both items were not contaminated. There is not a chance this was installation error, especially since there was no issue the first 5000 miles. As far as my research told me, bleeding is not necessary for changing pads and rotors.

A few days after the incident, I noticed the brakes felt 'weird' and sort of vibrated. This is when I scheduled an appointment with Mazda to check things out professionally. Tech told me the rotors had heat spots and the front needed to be resurfaced. After I got the car back, the brakes felt better, but still had the vibrating feeling. I inspected all four corners at this point and found the grooves in the rear rotors. Prior to this (just as you said) I have not seen one hard braking event damage a set of rotors like this, yet here I am.

I'll be removing the pads and rotors to install new in the spring when the car comes out from storage, if you follow up then I can tell you what I find. I could rationalize the grooving to debris and possible caliper sticking (even though two calipers sticking seems unlikely).

This still does not resolve the heat spots on the front rotors... I am not sure I appreciate the insinuation happening either. I continued this conversation hoping to get resolution on why I had an issue.

40w8

Man, you write lots, but don't have much understanding.

I'm only telling you what it's not to speed the solution up.

If you think I'm snarky, there are several members here that will really **** you off.

NOw your answer might lie with your first trouble of bottoming car, and bending or cracking suspension arms, etc.

Apparently, the Mazda Tech didn't figure it out, or he'd have your car fixed right.

Just keep taking it to him until he finds it or you run our of money.

LiveWire

iTrader: (1)

Rude and helpful is fine, rude and not helpful, why even post.

skc

Made a number of changes to the vacuum lines in my Hymee supercharged car and went to the drags without getting it re tuned.

Ended up with a blown engine..Doh

mazdafan1892

Drive for months with a coolant leak thinking its normal to replenish when one uses their ac as much as I do for an hour each work day. Other than that? Shutting it off cold the first year I got it and not checking the engine oil dipstick. I think I take the crown when being dumb for my car.

MiRe

So not my **** up, though I don't doubt I'll have my own:

A few weeks after I got my (very used) RX-8 at 135k miles, I got a CEL for a misfire. Figuring the previous owner hadn't replaced the plugs very recently I got new wires and plugs and replaced them. As you all know, there are leading and trailing plugs for the 8. Turns out the previous guy had put two leading plugs in one rotor and two trailing plugs in the other, despite the L and T literally CAST INTO TH ENGINE. As far as I can tell there were no long term issues because of it but it certainly has run better since getting new plugs and getting them in the right places.

CarbonRX

Hi, at the start of September 2020 i got a S1 rx8 with a blown motor. So i bought a S2 Engine, I thought it would be a easy weekend job. That is before i found this site.
I was so wrong 9 months later and the car is on the road, but still with 2 lights on the dash.
But loving the engine and the RX8.

TeamRX8

iTrader: (25)

pretty easy to do with a remote oil filter if you either don’t know or aren’t paying attention

https://www.rx8club.com/rotary-swaps...7/#post4941947

trying to pump oil the wrong way through an oil filter with an anti-drain back valve = no bueno
.

Brettus

iTrader: (2)

One of those mods I just shake my head over . All that effort for what ? ..... introducing several possible modes of engine failure all for the sake of saving one min. on your oil change ...no thanks.

kevink0000

My most memorable Dumb Thing occurred on my 1983 FB. I was 20 years old and was having a problem with the car stalling randomly. It turned out it was one of the many EPA mandated valves to control backfiring, noise, emissions, etc. I set out to disconnect it since I was too cheap to buy a new vacuum diaphragm. I took the carb off, started pulling the pin for the linkage off the manifold shaft, got it clear, and DINK, it popped out of my needle nose pliers and went flying down the (uncovered) intake manifold. I tried everything to get it out with the engine in the car, no good. It would cause the engine to lock in both directions when turned by hand. I priced a gasket set and seals and found that it would be worth it to just do a shortblock, which at the time, due to a connection at Mazda was only about $850!! I never forgot that. Too cheap to buy a vacuum motor, so I had to buy a shortblock! I try to close up any openings immediately now. Also, I tried to get the pin out of the engine while it was out of the car, and never could get it out, even tilting the engine and using gravity, despite the fact that this was a PP exhaust 12A engine.

Jerakl

Forgot to bleed the clutch after I changed it.
Noticed the white smoke coming out pretty quick and realized what I'd done.. (or not done)\