996 brake judder

[Automental]

Just bought a 2002 996 Carrera 2 and I'm very pleased with it but I've noticed that the brakes judder quite badly when hot and braking from speed.
Does this mean the discs are warped or might it be because it's done very few miles over the last few years and it will all bed in, he asked hopefully?! The discs don't look scored and there is no lip around the edge so I'd imagine they're not that old.
If it needs discs any idea of costs?
Thanks in advance.

[mr pg]

The discs have a tendency to corrode on the inner faces where you can't see, and cause this. Worth getting underneath and giving them a check. Made worse on a car that doesn't do many miles.

[churny]

mr pg said
"The discs have a tendency to corrode on the inner faces where you can't see, and cause this. Worth getting underneath and giving them a check. Made worse on a car that doesn't do many miles."

+1 to the above mine looked ok but were corroded at the back, new disks and its all sorted

[F3RNANDO]

Didn't the PPI pick up the discs?

I would get an educated opinion and if need be replace discs and pads so that you can enjoy the car the way it should be.....slow in fast out needs decent stoppers.

[Magic919]

Might just be pad transfer.

[mrdemon]

+1 I bet the disks are fine and its pad transfer

[F3RNANDO]

Magic919 said:

Might just be pad transfer.

Rectified with an Italian tune up?

[Rockster]

F3RNANDO said:

Rectified with an Italian tune up?

Probably not. A brake bed in operation didn't remove the light pulsing my VW Golf TDi's brakes developed when I let the car sit after washing then used the brakes hard to bring the car to a stop. The heat caused pad material transfer that stayed for scores of thousand of miles. Because it only appeared under light braking and I avoid this type of braking it was never an issue with me and I lived with it. When I sold the car at over 120K miles on its original brakes the new owner during the test drive of course lightly braked the car and noticed the pulsing but she bought the car anyway.

Since in this case the pulsing is very severe the rotors will have to be resurfaced if there is enough material to have them afterwards of legal thickness.

If not then replacement is callled for.

But first the brakes must be closely/thoroughly inspected to ensure corrosion of the inner rotor surfaces hasn't resulted in loss of delimation/flaking of material from the surface of the rotor that accounts for the pulsing.

This inspection must be done before any attempt at "fixing" this by a brake bedding in process -- which I believe will prove futile -- is done.

[Magic919]

F3RNANDO said:

Magic919 said:

Might just be pad transfer.

Rectified with an Italian tune up?

Performance friction pads have been used with some success.

[Automental]

Thanks guys. Sorry to be ignorant but what is "pad transfer"? I'm assuming it is pad material sticking to the discs and this might improve with use??

[graemel]

I'd suggest inspecting the discs for corrosion on the inside of the disc. Replace if rusty and resurface if not as long as there is plenty of meat left on the discs.

[Trev450]

Automental said:

Thanks guys. Sorry to be ignorant but what is "pad transfer"? I'm assuming it is pad material sticking to the discs and this might improve with use??

It is. Can often be cured with a few hard, high speed slow downs. The technique is to brake from say 70 mph as hard as you can down to about 20 mph and repeat that process a few times. Don't bring the car to a stand still and avoid resting your foot on the brake pedal when stopped after a spirited drive.

[Automental]

Thanks Trev450 I'll give it a go

[Rockster]

Magic919 said:

Performance friction pads have been used with some success.

Switching to pads made up of different (enough) material might just do the trick after of course a bedding in process is done.

It costs a set of pads but that's cheaper than replacing rotors and I suspect cheaper than having them resurfaced and still have rotors of the legal thickness.

Worth a try.