718 GT4 Noisy Rear PCCB

[Gonzo0]

Finally got our hands on our second Porsche last month and it is a beautiful 718 GT4, importantly fitted with PCCB.

One thing we have noticed is that there appears to be a rubbing/grinding noise coming from the rear under low speed braking. Had the car checked over by a master tech at OPC and he inspected the rotors and calipers and found nothing untoward, no scoring on the rotors or anything.

After leaving the OPC the noise continued, again under low speed braking. The car has only done 700 miles. Took a friend out who has had Aston Martins, Ferraris and Porches all with ceramics and has never heard this noise before. Anyone else noticed this on their GT4 with PCCB?

Tried a few high speed emergency brake runs but this hasnt resolved it either.

 

[ralphmusic]

Perhaps have the technician ride in the car with you?

 

[Motorhead]

I would have thought the tech would have checked for a stone caught up a rear brake assembly, but you could try reversing for a reasonable distance to see if that clears the problem.

Did he check that the handbrake was adjusted correctly and not binding?

As Ralph suggests, get the tech to ride with you next time to experience the problem first hand so the Centre can't fob you off again.

Jeff

 

[Gonzo0]

There was a very small stone removed from the parking brake which is apparently a separate shoe.

Think i best get back down to the OPC then for a closer look.

 

[BrianJ]

If the caliper design is similar to others, suggest you take the wheel off and with a torch look down the back of the disc from above including all the caliper crevices. In my experience, there's a high likelihood that you'll find a tiny stone in a crevice resting against the disc. They can make all sorts of horrendous noises, and can last for months. For some reason technicians don't seem to be able to find them, probably because they are generally looking from below. If the PCCB arrangement is sufficiently different from steel and there are no specially-designed stone catching crevices, please excuse my ignorance!

 

[gmcraib]

As others have said, it will be a small stone.

It sounds absolutely horrendous, especially with PCCB!

But fear not the surface of the discs are harder than stone and if caught between par and rotor (which is unlikely unless driving through gravel) the stone will be grinded away.

The quick fix to this is to reverse. Viola, nasty noise gone!