Rapter

Hello

I purchased a pre-owned 2017 4s with standard red caliber steel brakes.

I feel that the stopping power is not as immediate or strong as the brakes should be.

I suspect the pads or the rotors or both have some glazing as the braking can best be described as initial brake-trailing, then moderate braking. The brakes don't feel sharp as they do on my BMW for example upon depressing the pedal.

Pedal is firm.

Is there a best-practise procedure to remove the glazing that others have found successful?

Is there a way sharpen up the initial brake engagement ?

I have tried some hard driving on back roads with an emphasis on braking to see if that would help it did not... I have tried a series of high speed stops (80km to 20km and repeat 4x) which also did not work.

In summary I would like better initial bite when pressing the pedal.

Looking for some helpful suggestions.
Thanks !

arter

RE-bedding your brakes would be the first step.
Do 12+ high speed stops ( 110km to 20) back to back till the brakes are very hot.

That should remove the glazing.

If that doesnt work, then you might need new pads or a street/track pad that will have more bite.

Need4S

Rapter

Great point !

I will pull the pads out this weekend and check to see if they are Porsche branded brembo or something else.

Does anyone know off hand what torque the callipers should be tightened back to once released ?

mgordon18

The 2 big bolts for the calipers? For a 991.1 S it's 63 ft/lbs. I assume it's the same for 991.2, but not 100% sure.

Rapter

Yes the two large torxs bolts holding the calliper to the strut.

I found similar information on the diy brake change thread - where on the 991.1 the torque was 63ft/lbs.

It will be interesting to see if the torxs bolts have been marked up from tool use to indicate there was a change made from stock to low dust pads.

mdrums

tstafford

This would be my first step. I don’t think what the OP did was sufficient to get heat in them. I’d want to be able to smell them and then I’d feel I had them at temp.

drcollie

Yes caliper screws stretch and you are supposed to replace them each time if you go by the book.....I'm pretty comfortable re-using them myself, I think one year I did like thirty-five pad/rotor swaps for track days - that's a lot of caliper screws!

3Series

LOL. That's a lot of swapping in a year....but I hear ya, I used to do the same thing. I don't swap anymore but I used to change the bolt every two years, after about 20 removals.

Some folks I know use a dab of blue loctite but I've never used it.

Rapter

20 removals.... and 30+ removals on the post above. That is an obscene amount of pad swaps!

How did the rest of the car hold up from such use /abuse !

Pep!RRRR

Rapter

Car is a 2017 and has only 13k for total Distance traveled. Unlikely, but not impossible, that brake fluid could be ready for a changed car could have possibly been tracked and the brakes cooked.

Pep!RRRR