Rear Brake Caliper Bolts Size

[Beetlebum]

Hello have a 2005 955 3.2 V6, changing discs on the rear, calliper bolts are they M triple square or equivalent to a T60 my T50 no good and has less/larger spacing splines also
thanks

 

[Lancerlot]

I believe the rear calliper mounting bolts on the Cayenne require a 16mm XZN Triple Square tool.

Regards,

Clive

 

[Beetlebum]

Thanks for the info

 

[Lancerlot]

You're welcome.

The Cayenne uses this type of fastener for brake callipers because the bolts require very high torque and the XZN configuration distributes load evenly across its 12 faces, thus preventing cam‑out (slipping) and allowing the bolt to be torqued and re‑torqued without damage.

Regards,

Clive

 

[Beetlebum]

Hi Clive it’s odd as the ones on the front calliper were 21mm Hex bolt, did the front discs first!

 

[Lancerlot]

Interesting. Some older models use T55 Torx too. Clearly some discrepancies here Unfortunately I don't have a Cayenne to check, but here's what AI has gleaned for what it's worth!

Summary table​

Location	Correct tool	Evidence
Rear Cayenne calliper mounting bolts	16 mm XZN (Triple‑Square)	Listed explicitly for Porsche Cayenne rear callipers by tool manufacturers.
Front Cayenne calliper bolts (for reference)	16 mm XZN also appears in front‑caliper tool lists	Pelican Parts lists a 16 mm XZN driver in the toolset for Cayenne calliper work.

Regards,

Clive