I have a very strange problem. I have a F430 Spider 2009 with ceramic discs. Every two years our government requires a car have a mandatory check. That was done today and the brake test failed with 32% difference in brake power between left and right and 28% variance on the left front. This is very odd to me as the car had absolutely no rattle in the steering wheel when I parked it for the winter back in October and also braking hard without touching the steering wheel was still in a straight line. My F-dealer says I need new discs as they are warped, new pads and possibly a caliber refurbishment. I had a test drive in it 4 weeks ago and nothing was wrong with the brakes. Another thing they found was the wheel hub bearings and I know I need new tires. So could the brake variance maybe come from flat-spot tires, loose bearings and dirt from being parked half a year. Any input to similar situations would be greatly appreciated. I am going to the dealer tomorrow to drive the car and do some hard brakes to clean the surface.
I remember a Wheeler Dealers show where they had a car fail that test as well, WD follows England DOT rules. I don't recall what the issue was well, but I thought it was related to pressure being unequal between the calipers. To Brian's point, I don't think Ceramic rotors could warp, and even if they could it shouldn't cause that kind of difference, especially without noticing a pull or vibration. Brian's dead on, find someone else to go over it.
My money is on sized caliper pistons. It's a pretty regular occurrence on the CCM calipers, at least in Europe
P.s. A caliper rebuild is not expensive. Hill sell stainless pistons that are designed to prevent this very issue.
By any chance have you been less than diligent about getting your brake fluid changed? This is especially important for a car that sits as usually is the case for Ferraris in northern climates. Moisture finds its way in and corrosion and braking performance suffers. ABS, as great as it is, masks this issue as it will compensate by releasing pressure to the better performing corners as they will lock up first. So, you car will brake straight but just take longer. Possibly a fluid change will remove the contamination and allow equal pressure to the calipers. If this has recently been done, it could be as simple as requiring the lines be bled. Air in the lines will also cause the same issue ...and contaminate your fluid meaning a change is also required. Anyway, something to consider before rebuilding your calipers.
+1 Just have the calpers rebuilt- very inexpensive, flush your brake fluid more often and avoid all these problems. Brake fluid attracts water (heating & cooling)and once it's in the system the Pistons corrode and get stuck causing the unequal brake force. Shouldn't cost more then $250 USD per calper from any independent race shop. (A bit more if the corrosion was very bad and Pistons need replace) Even if you don't use ur car change all the fluids every 2 years max. That includes brake fluid, f1 fluid, power steering fluid, transaxle fluid, coolant, and of course engine oil.
By the way if the f1 fluid has not been changed the same process will occur but will cost many thousands of dollars to fix the corroded actuator.
May not be crookedness as it is as much incompetence. Part replacing! Got a problem replace it all that will fix it. Sadly, some very bad mechanics make lots of money fixing what they don't know or fixing problems they create.
Yes a rolling road where the brake force is measured individually while applying more and more pressure. The fluctuation is measured by holding a constant pressure, then the force is measured while the wheel turns. So brake calipers out, massaged them, bleed the system, swapped pads and changed the broken whisbones and now no fluctuation and less than 5% difference in brake force between the wheels (to be road legal difference must not exceed 20%) So only changed part was wishbones and they were covered under New Power warranty. Thanks for all the input
Good test if it discovered busted suspension components, even if that is not what it was trying to test. Really bad diagnosis by the dealer.
Interesting perspective...an alternative view is that the most critical system on a car for safety is the brakes, so mandating a certain threshold of predictable performance makes sense. I'm stirring the pot a bit, but I can see both sides.
