Front Brake Disc Drilled Holes Filling With Crud

[mr pg]

I did the discs on my prvious 996T a couple of times with a 4mm drill. Quite rewarding and easy to do. Will probaly end up doing my 981CS too.

 

[Steve Brookes]

Chris,

After quite a few track day outings I can confirm that high rear pad brake wear does seem to occur, presumably due to the action of the PSM system. However, I can't recall having seen the PSM warning light flashing at any time while on track.

I must say that I was rather surprised when I discovered that the rear pads appeared to be worn more than the fronts when I checked, although if - as Kevan has pointed out - the rear pads are thinner than the fronts then perhaps the wear rates are very similar.

Jeff

When tracking my CR with PSM on in dry conditions the light never flashed. When I turned it off the light flashed on the exit of just about every corner! I've yet to work out what that means! My guesses are:

1. When off the PSM is not helping me but it's telling me I'm exceeding traction and grip.

or

2. When off and I've exceeded traction and grip the PSM decides it must intervene to help and lets me know that it is.

And when PSM is left on it continually does its thing to help but doesn't feel the need to tell me (hence the light doesn't flash).

 

[Buddy]

With regard to the wear grooving of discs, some have said in the past that it was caused by heavy braking but it doesn't always become apparent on all discs or just the front etc, more likely it is caused by a) not cleaning the disc face fully when fitting from new or b) slight defects in the edge of the holes caused by the machining process of the drillings, since discs wear in use and often don't groove the latter is unlikely, but sometimes the anti corrosion coating can be more difficult to remove from the disc faces although it comes off easily with isopropyl alcohol.

 

[Motorhead]

Chris,

After quite a few track day outings I can confirm that high rear pad brake wear does seem to occur, presumably due to the action of the PSM system. However, I can't recall having seen the PSM warning light flashing at any time while on track.

I must say that I was rather surprised when I discovered that the rear pads appeared to be worn more than the fronts when I checked, although if - as Kevan has pointed out - the rear pads are thinner than the fronts then perhaps the wear rates are very similar.

Jeff

When tracking my CR with PSM on in dry conditions the light never flashed. When I turned it off the light flashed on the exit of just about every corner! I've yet to work out what that means! My guesses are:

1. When off the PSM is not helping me but it's telling me I'm exceeding traction and grip.

or

2. When off and I've exceeded traction and grip the PSM decides it must intervene to help and lets me know that it is.

And when PSM is left on it continually does its thing to help but doesn't feel the need to tell me (hence the light doesn't flash).

Thanks Steve - some useful guesses there. When off I thought that PSM only intervenes when you brake or perhaps in extremis.

Generally I leave PSM on but will have to try turning it off next time out.

Jeff

 

[Brian_Innes]

Quoting from my 718 CS driver's manual, the following information is given when PSM is switched off.

"When you brake in the ABS controlled range, the vehicle is stabilised even when PSM is switched off. One-sided spinning of the wheels is prevented even with PSM switched off."

"When PSM Sport mode is active, it is only possible too switch to PSM OFF if the PSM was activated beforehand."

"PSM Sport should always be switched off during "normal driving".

In other words PSM is never truly OFF. The flashing of the PSM light warns the driver of PSM control functions taking place.

Brian