Brakes warped.... again!

[adamc11]

Well guys... i've managed to warp my new AP racing brakes that have done about 8,000kms. I get steering wheel shudder when i brake. I have given them a fair thumping, but still a little disappointed given their race brakes. If i brake hard to a stop, i always pull up the handbrake an don't keep my foot on the brake. I know water on a hot disc can do it, but i havn't really had the rotors hot in the wet. Any other ways to avoid warping brakes? They also squeel badly when they heat up too. Will have to machine them, get good pads, and hope it doesn't happen again.

[Ozzie]

Did you use cheap pads with the rotors?
Cheap pads can be nasty,
You might have a chance with machining them.

are the slotted, drilled or both?

[Ozzie]

also being an SS, it's an 8 right?
when you changed the rotors did you put V8 rotors on it

[adamc11]

There are no v8 rotors. It's a HSV AP Racing brake kit that was an optional upgrade on VY/VZ HSV's. See here: Announcements

Rotors are slotted and i used the standard Ferodo pads that come with the kit. Might get rotors machined and put on better pads... can anyone recommend a pad?

[danja]

I guess racing brakes aren't really designed to do 8,000km?

That sucks mate, I can imagine being pretty ****ed about that, especially given what those setups cost.

Only suggestion I can make is not to slam them so hard unless you need to, which is a generally good thing if you're on the road. If you're on the track.. well.. maybe you just need better discs?

[danja]

Might get rotors machined and put on better pads... can anyone recommend a pad?

I've always been a fan of Bendix pads. I went from Fedoro to Bendix and preferred them, because they stop just as well but weren't as harsh.

[adamc11]

I guess racing brakes aren't really designed to do 8,000km?

That sucks mate, I can imagine being pretty ****ed about that, especially given what those setups cost.

Only suggestion I can make is not to slam them so hard unless you need to, which is a generally good thing if you're on the road. If you're on the track.. well.. maybe you just need better discs?

Yeah well they just feel so good and work so well i can't help but stop at the last minute lol. But seriously, for what i spent, i would hope they wouldn't warp. Apart from that they have been excellent.. great pedal feel, no fade at all..can't have it all i guess.

[adamc11]

I've always been a fan of Bendix pads. I went from Fedoro to Bendix and preferred them, because they stop just as well but weren't as harsh.

The Ferodo ones are the dustiest pads i've ever used. I think minux runs EBC reds on the same brake kit (am i right minux?). I thought they were a semi-race pad? I wonder if the Bendix have pads available for the AP calipers...

[danja]

Yeah well they just feel so good and work so well i can't help but stop at the last minute lol. But seriously, for what i spent, i would hope they wouldn't warp. Apart from that they have been excellent.. great pedal feel, no fade at all..can't have it all i guess.

Yeah it is a shame. Maybe the discs just weren't that great? Are they DBA?

Maybe talk to a brake specialist and see what they reckon?

The Ferodo ones are the dustiest pads i've ever used. I think minux runs EBC reds on the same brake kit (am i right minux?). I thought they were a semi-race pad? I wonder if the Bendix have pads available for the AP calipers...

Yeah my Fedoros were dusty as **** too, a mech told me that they were racy too. Bendix are a big name game, I'd expect them to have pad for just about anything.

What do Holden use OEM?

[adamc11]

Yeah it is a shame. Maybe the discs just weren't that great? Are they DBA?

Not sure what rotors HSV use in the kit. I think i read somewhere that the kit isn't a full AP Racing Kit (as in it's a HSV kit with AP Racing Calipers only) therefore the rotors could be manufactured by HSV?

Yeah my Fedoros were dusty as **** too, a mech told me that they were racy too. Bendix are a big name game, I'd expect them to have pad for just about anything.

What do Holden use OEM?

I think Holden use PBR pads (don't quote me on it though). The ones with the kit were the Ferodo's though.

[Shounak]

Well guys... i've managed to warp my new AP racing brakes that have done about 8,000kms. I get steering wheel shudder when i brake. I have given them a fair thumping, but still a little disappointed given their race brakes. If i brake hard to a stop, i always pull up the handbrake an don't keep my foot on the brake. I know water on a hot disc can do it, but i havn't really had the rotors hot in the wet. Any other ways to avoid warping brakes? They also squeel badly when they heat up too. Will have to machine them, get good pads, and hope it doesn't happen again.

Squealing within reason isn't such a bad thing. Some of the more expensive race brakes do it, if you want quiet/non dusty, General CT's are the go.

You pull up your handbrake when stopping? Handbrake should only be used for parking, or maybe occasionally when stopped at traffic lights for a while and the car is in N. Unless you mean you brake upto the lights and instead of leaving the brakes applied, you put the handbrake on?

Rotors will usually warp due to driving , ie. riding the brakes. The amounts of times I drive behind people whose rear red light stays on amazes me. It'd probably increase 10 fold with commsirac's driving method. I personally treat my brake like my clutch, it goes in and out as I need it and never stays applied for long.

Also, have you been doing burnouts? They'll make a rotor red and if you drive around after burnouts it'll just mould your new discs in a new manner. How about your pistons? I'd personally pull the pads off and check that they're evenly worn on both sides. A siezed piston creates a hell of a problem.

I doubt the warping is due to manufacturer fault. Of course it might be, but then you'll get your money back. I'd bet it's one of the above though.

[adamc11]

You pull up your handbrake when stopping? Handbrake should only be used for parking, or maybe occasionally when stopped at traffic lights for a while and the car is in N. Unless you mean you brake upto the lights and instead of leaving the brakes applied, you put the handbrake on?

Nah no hand brake for stopping. Just use it once i have stopped so i don't keep a hot pad on a hot rotor which can cause warping.

Rotors will usually warp due to driving , ie. riding the brakes. The amounts of times I drive behind people whose rear red light stays on amazes me. It'd probably increase 10 fold with commsirac's driving method. I personally treat my brake like my clutch, it goes in and out as I need it and never stays applied for long.

As stated, i have been giving them a fair bit but for casual driving I usually just gear down if it's a hill or something rather than hold the brakes.

Also, have you been doing burnouts? They'll make a rotor red and if you drive around after burnouts it'll just mould your new discs in a new manner. How about your pistons? I'd personally pull the pads off and check that they're evenly worn on both sides. A siezed piston creates a hell of a problem.

No i havn't been doing burnouts. Not too sure about pistons. It's due for a service sometime this week so i'll mention it to my mechanic. Probably won't believe what i've done... he fitted them only a few months ago.

I doubt the warping is due to manufacturer fault. Of course it might be, but then you'll get your money back. I'd bet it's one of the above though.

Doubt i could make a warranty claim... too easy for them to say they have been mistreated.

[Shounak]

You'd be suprised. It's often just easiest for them to send you out a new set.

Send a nice little letter to head office stating the problem, outlining that you definitely didn't abuse them and maybe even point them to a link on JC here. I'm sure creating a thread with a whole bunch of people replying, "those dogs, am never going to buy em again" would jumpstart their efforts.

[FusionX]

i always pull up the handbrake an don't keep my foot on the brake.

Not a wise idea, as you can cook the handbrake shoes to the rotors.... not fun trying to get the car back moving, trust me. Even sitting in the one spot without the brakes on, the pads are creating a hot spot. At track days, every 30-60 second after a run I'll push the car a little bit forward to avoid the pads staying 1 one spot too long. Quite a few guys do this.

Warped rotors probably come down to the quality of the rotor. Standard HSV rotors are fine on the street, but not too good on the track, don't seem to like 550+ degrees.

[adamc11]

Not a wise idea, as you can cook the handbrake shoes to the rotors.... not fun trying to get the car back moving, trust me. Even sitting in the one spot without the brakes on, the pads are creating a hot spot. At track days, every 30-60 second after a run I'll push the car a little bit forward to avoid the pads staying 1 one spot too long. Quite a few guys do this.

Warped rotors probably come down to the quality of the rotor. Standard HSV rotors are fine on the street, but not too good on the track, don't seem to like 550+ degrees.

Hmmm... What rotors can you recommend then.

[Not_An_Abba_Fan]

Were the wheels torqued correctly? This is probably the number one cause for warped rotors. You have to torque them in stages in a star pattern. Do them up in a star pattern gradually tightening them up to around 80 Nm, then do a final torque to 110 Nm. not doing this will cause the rotor to "chase" the wheel nuts and will cause run out down the track, usually within a few thousand k's.

[Tom_1569]

Also machining warped rotos WILL NOT FIX THEM..... The shudder will go away until your next heavy brake and it will be back to how it was. Just buy new rotors and call it quits with the old ones.
And as NAAF said make sure the wheels are torqued, most mechanics just use a rattle gun to a gazillion Nm caus its alot quicker and easier for them.

[DannyboyDS]

can anyone recommend a pad?

I hear Libra are a pretty good brand.


Ok no sorry, I just use Bendix Ceramics, they have always proven to work well.

[FusionX]

Hmmm... What rotors can you recommend then.

I'm using DBA 5000 series. Good rotor, have apparently exceeded 630 degrees with them according to the colour stripes on the disc. No drama's with them with racing. Was going to use some Harrop 2 piece rotors, but couldn't get them in time for a track day.

[adamc11]

Also machining warped rotos WILL NOT FIX THEM..... The shudder will go away until your next heavy brake and it will be back to how it was. Just buy new rotors and call it quits with the old ones.

That's a bit depressing . I though machining them would fix it. I'm guessing warping permanently alters the disc not just it's surface?

And as NAAF said make sure the wheels are torqued, most mechanics just use a rattle gun to a gazillion Nm caus its alot quicker and easier for them.

Yeah not too sure about that. Will have to speak to the mechanics and see what they say about all this.

[Tom_1569]

That's a bit depressing . I though machining them would fix it. I'm guessing warping permanently alters the disc not just it's surface?



Yeah not too sure about that. Will have to speak to the mechanics and see what they say about all this.

When they warp, the internals of the rotor are warped and damaged, machining only effects the surface, so they will be flat, until you get heat in them again and it will warp the surface back because the internals are warped. Hard to explain, just trust me, mum had warped rotors, paid 45 bux a rotor for machining, 200km later they were warped again and got worse alot quicker. If my 50yr old mum can manage to rewarp them under her daily driving, I would imagine they wont last you very long.

Torqueing wheels
If you have a look at how these are attached it will make sense very quickly. The wheel holds the rotor in place. When fitting the rotor it is impossible to get it 100% on and tight, so if you just do them up by hand or with a rattle gun it makes it difficult for it to be on 100% flat out. If there torqued in stages it makes the right torque and more chance of it being 100% flat.
Some mechanics/tyre fitters are happy to use a torque wrench when asked, but some wont even, thats why I take the wheels off and drop them off when getting new tyres, or be there whilst the work is being carried out.

[greenacc]

parking a car with hot brakes is bad, as said above .... so when your out driving ease off the brakes when your a few k's from home or wherever your going to let them cool down evenly before you stop.

[235rwkw]

The Ferodo ones are the dustiest pads i've ever used. I think minux runs EBC reds on the same brake kit (am i right minux?). I thought they were a semi-race pad? I wonder if the Bendix have pads available for the AP calipers...

ferodo are dusty but very good at stopping, best stopping pad i've used. but damn dusty..

been using ebc greens, not quite as good, less dusty, prone to get crap on the rotor if not used hard.

warping, yes torque up the nuts evenly

[VT-565]

The first thing I would do is get a hold of a mag based dial indicator, take the wheels off and check the disc runout. Contact someone at AP for a tolerance figure (around 0.004" ?), to see if they TRULY are warped. No use getting them machined if they aren't.

[immortality]

Were the wheels torqued correctly? This is probably the number one cause for warped rotors. You have to torque them in stages in a star pattern. Do them up in a star pattern gradually tightening them up to around 80 Nm, then do a final torque to 110 Nm. not doing this will cause the rotor to "chase" the wheel nuts and will cause run out down the track, usually within a few thousand k's.

thats good to know, now i'm happy about been a little anal about the way i fit my wheels. i've never warped a rotor and i get em plenty hot. must be doing it right

talk to GSL rallysport. he does a line of brake pads (QFM????) that seem to perform better then the EBC pads but with less dust and seem to be rotor friendly

slotted rotors seem to be the go, bit harder on pads, but better pedal feel as the rotor "wipes" the pad clean every rotation