981 Cayman S braking issue

[AndyMort]

Noticed an issue with the brakes the other day. About 12 degrees outside and Id been driving about an hour so the car was warm. When braking hard..very hard...I felt a rumble through the brake pedal. It wasn't an ABS rumble, and feels more like wheel locking. I got an observer to watch and they did say the wheel was locking and skidding.

The brakes themselves do feel a little spongy so fluid could have overheated at last track day. The pads themselves are low but nowhere near sensors. The tyres are low but they still have grip. Anyone heard of this before. I woul dhave thought the ABS would have kicked in rather than locking the wheel?

[JayK12]

AndyMort said:

Noticed an issue with the brakes the other day. About 12 degrees outside and Id been driving about an hour so the car was warm. When braking hard..very hard...I felt a rumble through the brake pedal. It wasn't an ABS rumble, and feels more like wheel locking. I got an observer to watch and they did say the wheel was locking and skidding.

The brakes themselves do feel a little spongy so fluid could have overheated at last track day. The pads themselves are low but nowhere near sensors. The tyres are low but they still have grip. Anyone heard of this before. I woul dhave thought the ABS would have kicked in rather than locking the wheel?

ABS won't stop all lock up's but will help. Your probably feeling ABS modulating under the brake pedal when it locks up? Mine locks up in the summer when braking very hard, PZero's just don't have enough grip imo. I dont think there's anything wrong,

[AndyMort]

It's a fair point and I will be getting Michelins next, but I didn't notice this when last on the track...which was why I thought it odd.

[gtsralph]

Might also be pad deposits on the discs. The front pad new is around 17mm of which 6.5mm is backing plate so 10mm or so pad material. Difficult to be sure from the image but your pad thickness looks less than the backing plate.

[gsewell]

When you were on track, the tyres were up to a proper working temperature and will have had a lot more grip and so would not have locked up.
In the cold and with worn tyres, the levels of grip are much lower.

[petej]

Seeing a fair amount of corrosion in the pic, so check the disc surface on the rear faces for corrosion and uneven wear.. discs far more likely to require replacement for corrosion than wearing to minimum thickness.

[AndyMort]

I'm thinking it could well be time to replace the discs pads and new fluid. Anyone got an opinion on best ones to get OEM as opposed to other makes, doing about 2 track days a year max so don't need to be too sporty.

[petej]

Euro Car Parts

Pagid for keener price or Sebro for oe quality