perryth

I've developed a prety good shake while braking from 70 to 50 that I am assuming is front rotor warp. The car only has 16k on it and its mostly reasonable highway driving. Its not like I have been out road racing and overheating these things.

Is this a common problem? Recommendations on aftermarket replacements?

badjuju342

iTrader: (3)

I've heard quite a few folks on here talking about warped rotors so it is quite possible.

nbm02ss

All of the late 4th gens have bad rotor warp....only way to get rid of it is to buy different rotors. Ive just dealt with it on my 2 maros

GETGONE

iTrader: (5)

Mine warped at about 13,000 miles. It was still under warranty so I took it to the dealer and they turned them. It's been fine since. I've put just over 5K miles on it since. It's a common problem with LS1 F bodies. Lots of people just replace the rotors with aftermarket upgrades. I thought about it but figured I'd use the warranty and wear these out first.

Jimmyz

iTrader: (3)

yep, totally normal. get some new rotors from the guy that runs the GP's on this forum. Wholesale Direct or something like that. I have them and for the $$$ you cant beat this one piece rotor. I would suggest NOT getting crossed drilled. I got them slotted only and cadnium platted.

https://ls1tech.com/forums/sponsor-sales-specials/433110-cross-drilled-slotted-high-performance-brake-rotors-pads-kit-299-00-shipped-save.html

02SS:ZEUS

iTrader: (16)

I'm at 45k with my 02 SS, and the rotors are still working fine. I bought the car with 30k on it, but it still has the same rotors GM puts on the SS, so I'm assuming they are the original rotors(unless someone would actually use factory replacements?!) I use the transmission to slow down a lot, so that might have something to do with it. As far as replacements, it depends on how much $ you want to spend. You can buy the same size rotors, drilled and slotted, for about 100$ each, or you could go to 13.5" rotors, which of course would require new calipers, running about 2k for the fronts, and 2k for the back.

SS1875

iTrader: (34)

Mine warped at 15,000...bought some Power Stop rotors..car now has a little over 43,000 on it, and they are still going strong. Pricing is very good on them as well.

BULLET99Z28

iTrader: (9)

Common on Many GM later model cars. I have heard the rotors do not have enough material, thus saving weight.tahnks for being cheap GM

ZeeVert

"Warped" rotors and pulsing brake pedal has been a problem for many, many years. Any car can fall victim.

While heat can certainly warp your rotors, it really takes a lot of braking to generate that kind of heat... more than a typical driver would do.

A more common cause of brake pulsing is warping and run-out caused from incorrectly torquing your lugnuts. This is why it is highly recommended that the nuts be torqued correctly and in a star pattern. Tighter is definitely not better... use a torque wrench.

Supposedly, the biggest cause of pulsing and shaking brakes is rotor thickness variation. And that variation is generally caused by uneven rotor wear because of rotor and/or wheel hub run-out (r/o). This will usually show up at 15-25,000 miles. Sometimes, replacing or turning the rotors seems to fix the problem, but it will return in 15-20,000 miles, because the real problem hasn't been fixed. Your best chance to fix the problem is to have your rotors turned on the car. This should totally eliminate both thickness variation and r/o. The second best plan is to really clean the wheel hub face and use a new rotor. If you have an indicator, put the rotor on in each of 5 positions and use the position with the lowest r/o.

The target run-out on the wheel hub face as-manufactured is about 0.025 to 0.010 mm (0.0010-0.0004 inches).
If the r/o on your rotor face is less than 0.050mm (0.002in), you're probably in good shape.

I personally do not recommend having your rotor turned off the car. Either don't turn 'em or get new rotors... and don't turn your new rotors. Turning the rotors will probably make them worse, unless they have a way to independently gage & verify the r/o.

And guess what? I went so far as to use new bearings and rotors to fix a pulsing brake on an '92 Cadillac... and it didn't work... pulsing was back in 20,000 miles.

Then again, my '02 Impala had pulsing brakes at 25,000 miles. I did nothing, and the pulsing slowly disappeared at around 80,000 miles. (by now I must need pads).

I can't believe how long this turned out to be, sorry and Good luck!

300bhp/ton

As far as my research has lead me to believe. Warped discs DO NOT EXIST. In every case the cause is something totally different.

In race cars there is often a claim of warped discs and in almost every occasion it is due to an uneven carbon build up on the surface of the disc not warping. If you want more info do a search on Google.

Other reasons why you might have brake judder could be a worn bearing, broken or mis-alinged front geometry. Uneven tyre wear, warped rim (common probelm with many modern aftermarlet rims). Or a sticking piston on the caliper.

Also if it where a warped disc, then the disc would be warped no matter what speed you brake from, so the judder would not occur at particular speeds but ALL THE TIME.

Another thing to note is the ABS does seem to kick in way too early on these cars, if I brake moderatly hard at speed in my Z28 the brake pedal will pulse and braking affect will slightly reduce. To the untrained foot it would indeed feel like a warped disc, but it is infact the ABS. Whether this is by design or not I don't know. But many times I have heard people complaining of warped discs in their Fbody and then description they give is of the ABS activating.

So if the pedal starts pulsing again just apply more pressure to the pedal, the pulse will remain but the car will pull up better. Whether aftermarket pads/disc will slove this I have no idea (but will be trying it out in time).

Another way to tell if it's the disc, is does the steering wheel judder also, because if it is directly the disc/pad causing the judder then the steering wheel will violently judder also. I would also expect the car to have a very strong bias to pull heavily to one side also while under braking. And again this would be at any speed not just a particular speed range.

GETGONE

iTrader: (5)

Hmm...you say warpped discs don't exsist but yet you go on and give indications of what a warped disc would be. I had them on my car. IT WOULD violently shudder ANYTIME I'd brake and it was worse the higher the speed. You could still feel the pulsation slowing from 10mph but wasn't near as noticeable as when you hit the brakes from 60mph. After the dealer turned them they're fine. There was no other problem.

ZeeVert also says not to turn new rotors. I got into an argument on another forum about that as I had never heard of it. The guy claimed that runout was not always perfect even from the factory so he always turned his new rotors to make sure they were perfect. I've never turned new rotors and never had an issue.

300bhp/ton

True i did say it does not exist, this is mearly quoting what I seen written by true industry professionals.

A warp disc can still exist however, but due to manufacturing or some form of damage, actually warping of a disc as in terms of normal operational use is what I was referring to.

As for your disc, which you had turned. Well it doesn't prove that they where warped, as turning them would remove an uneven carbon build up thus solving the issue.

Please don't take my previous post as law, it is mearly a collection of researched knowledge. And logically speaking I can not seen any evidence of true disc warping due to use.

I have come across many examples first hand (have owned/driven lots and lots of cars) that would appear to be warped discs. None of them where.

That aside, following the description from the thred originator it still sounds like the ABS to me. Unless of course their car isn't equipped with ABS then it won't be that.

GETGONE

iTrader: (5)

I highly doubt it's ABS. 50-70mph is where the shaking is most violent and noticeable when driven on the road. Below 50 for me it still shook but wasn't near as noticable or annoying. I could still feel the pulsations. I saw no build up of any kind on my rotors and they only had ~11K miles on them. I think drag racing and repeated slowing from over 100mph was the cause of my rotors warping.

Lucas'02SS

iTrader: (4)

My rotors did the same around 16,000 miles. My car doesn't shake, but it pulses steadily at whatever speed. There is no way mine is the ABS.

jimmyblue

iTrader: (11)

I've had minor shimmy come and go, related to high speed abrupt
braking. I believe a single, high-rate-of-heat event -will- warp a
metal disc (see it all the time with circular saw blades, if the edge
and center are not uniformly heated the edge will "outgrow" the
center and potato-chip). Cooldown can "freeze it" as-warped.
Braking fast from high speed provides a very large heat spike
potentially and this will have a large radial temperature gradient.

But too, sticky slider pins (a common problem too) can make the
calipers not want to follow the rotor at all and greatly magnify
the problem I expect.

300bhp/ton

If it's violent does it also shake the steering wheel?

My friend had exactly that problem and at similar speeds. He thought it was warped discs so changed them. No difference, it turned out to be a sticky piston on caliper which was not retracting correctly.

As for use, well in all my cars the brakes get a real pasting, comes from living where there are twisty roads I guess. I've had solid disc, vented, grooved, X-drilled and combinations of the above on ABS and non-ABS cars. I've managed to cook the brakes so much that the brake pedal feels like a clutch pedal. So they are certainly getting HOT.

But never have any of them warped, this includes big heavy vehicles like Land Rover Discovery's I've heated the brakes so much that it turned my white painted steel rims a horrible yellowish colour.

2001WS6Vert

I can warp the rotors on one hard stop (at the track), so I try to evenly slow down till the last turn off. Warped rotors is common in virtually all cars. Every model car I've ever owned warped it's rotors. They can be machined off the car and will be fine. I machine rotors almost everyday on customer cars and on the test drive they brake perfectly smooth. True the wheels should be torqued but some here are just overcomplicating this. I'm a real stickler with any car problems and usually turn the rotors at least once between brake jobs because of warped rotors. If you don't want it to happen buy the aftermarket ones and see if they help. I've heard that they work well.

GETGONE

iTrader: (5)

Heck yeah it was shaking the wheel! That's what got so annoying and I took it to the dealer to get it fixed. It shook a LOT when braking from 50mph or above. Below that you could feel it shake but not quite as bad. After the rotors were turned(off the car) it was fine and is still fine about 6K miles later. I've been drag racing a lot since they were turned too and the warping hasn't returned yet.