Rob123 wrote:if they say you get the juddering even thought the brakes arent warped this obv. doesnt apply to you, but the main cause for warped brakes it people not using the handbrake and sitting at a standstill with their foot on the brakes, especially when you have braked hard and the brakes are very hot, the pressure causes them to be crushed by the pads and they come out of shape. thought i'd just ge that in there,
could be unbalanced wheels, just get everything checked, could be problem with a wishbone or a top mount, anything really! probably a bit extreme and unlikely, but ti may have been in a crash and have a twisted chasis or something, i only say this because its a new car to you and you may not know its history.
i dont like to be pedantic but thats not 100% true.
ok a brief how brakes work tutorial.
when brakes bed in ( new disks and pads) the brake pad rubs off a small layer of pad material onto the disk and it fuses to the disk and makes the disk "sticky" so now when you brake you have 2 surfaces coated with the same matiral meaning you will have efficiant braking. ok there is the how they work
this is a track situation ( not as extrame as on teh street but principal is the same)
you have had a ragging session and you have come into the pit lanes for a cool down and something to eat your brakes are glowing so you stop in the pits and wack your handbrake on your pads hit the rotor and start cooling down through dissapation hot rotor hits cooler pads and transfers heat to caliper and brake fluid and anything it can get to. meanwhile the pad material is fuseing to the layer of pad material on the disk.
so you now release the brakes and goto move off they release but leave a pad imprint on the disks causing a high spot on the perfectly balenced rotor. so now your braking again and you feel a pulsing sensation similar to warped rotors. but its the pads hitting the high spots and moving trying to erode the high spot down to level with the rest of the disk but it wont work as it builds higher with each application of the brake as it removes more pad material.
moral of the story in pit stops leave the car in gear engine off handbrake off.
at traffic lights put handbrake on and take foot off brake. ( rear drums/disks stay cooler thus meaning you can have them engaged and not leave an imprint.
( i wish i had have taken a photo of my rear disks before i had them resurfaced you would have seen a pad high spot.
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I gave up in the end and sold the car on. I hated passing the problem on to someone else but i was left with no choice... i just couldn't afford to keep throwing money at it. Hope you have more luck than i did
