Stock brake discs getting warped after 20000kms

[markovr]

I always had this drama on my vz with stock brakes ... Had different brands of front discs.... some aftermarket but it always ended up happening and when they got hot it was much worse....anyone had this drama and found a solution?
Someone told me it was bearings worn but I'm not sold.
I even took front discs off my vr (no problem after probably more than 20k ) and put them straight on my vz with pads from same side etc no problems initially and on the vr braking was fine but the vz did the shimy thing after a while ... Discs looked worn but not badly but when they machined them they took quite a bit of metal off to get them true... Seems like something with that car or the driver?

 

[diysv6]

Can you set up a dial indicator/run out gauge on the caliper and other reference points to see where the warping is occurring?

My understanding - when getting the rotors refaced, the machinist takes most of your residual safety thickness in the quick approach to get them true. They take the rotor to minimum legal thickness - lazy way of truing up the rotor faces. Sounds impressive - we removed 3mm to get rid of the warp!

Some members report -
If hot minimum legal thickness rotors get wet then can warp.
The cheaper rotor assemblies cannot take a full reduction to minimum legal thickness, take the heat and a fast cool down.

 

[markovr]

This article mentions the bearing drama

 

[VK SL 3800]

Ive had the same problem with the front left on my VS ute, a new wheel bearing did fix my issue.

 

[CONROD]

Might not be relevent to the problem, but I know Ford sent out a service bulliten relating to warped discs on BA falcons and in was caused by not tightening the wheel nuts in secquence eg; 13524 to pull the wheel on square and also to avoid using a rattle gun to finsh off the tightening process, Ive never had a problem on the ute but I do know some people tighten the **** out a wheel thru fear of one coming off. Like I said it might not relate to the above issue,

 

[vc commodore]

Might not be relevent to the problem, but I know Ford sent out a service bulliten relating to warped discs on BA falcons and in was caused by not tightening the wheel nuts in secquence eg; 13524 to pull the wheel on square and also to avoid using a rattle gun to finsh off the tightening process, Ive never had a problem on the ute but I do know some people tighten the **** out a wheel thru fear of one coming off. Like I said it might not relate to the above issue,

I have been tightening wheel nuts out with rattle guns for more years than I care to remember.....Never struck the issue. And yes I have worked with plenty of fresh faces in the industry and I have also corrected plenty too.

When the wheel is off the car, the rotor does protrude out at the base more that the top....This is because the pads don't touch it......Even still, you still can't warp a rotor by over tightening one single wheel nut, nor not doing them up in the correct sequence.

When the BA was introduced, the main issue with the rotors was, they were made from crap metal (Actually it started with the AU 11 from memory)......The braking system was a big improvement over the previous model (single piston caliper to twin piston caliper) and like all car manufacturers, were trying to save a dollar, hence they sourced crappy rotors which couldn't cope with the upgraded braking system.

I will agree, people tightening wheel nuts in the correct sequence seems to be a dying "art".....But after a few years of fitting interference fit rims, the youngins soon learn this is the only way to bolt them up, so you actually get all the wheel nuts up tight...