bobsan

nothing to do with caliper bolts etc. but cant help notice the OP's still got the remnants of three anti vibration pads that have broken off still left in one side of the caliper.

did you once use these pads now don't, do your brakes screech when cold at all ??

I'd love to ditch my pads if they're really not needed

LVDell

Those aren't my calipers

Orbit r

acadian_dad

I had assumed those were the puck retainer clips

acadian_dad

Warning for those looking to install these on a 997.1 GT3 (steel brakes). While it's clear that the one part is too short for the front brakes (the PCCB part) - the other part looks like it might work (that's the part that Orbit sold me and Eduardo provided the PN's earlier).

But when doing the front caliper this evening, I found that this part does not appear to be a direct fit (for my car anyway).

With the stud fully set into the upright, the shoulder at the other end of the stud was still proud of the nut to caliper mounting surface (so the nut can't hold the caliper securely). I only found this out after the preapplied threadlocker had set ...

I didn't want to take a blow torch to it to loosen it off ... so I set about to find a way to make it work.

In the end I found that four M10 washers stacked (about 8 mm total thickness) between the nut and the caliper spaced the nut far enough away from the shoulder that it could be torqued to hold the caliper securely. I may mill out a single bushing to replace the washers when I get some time - 20 mm OD, 10.5 mm ID (to clear M10 bolt) and 8 mm long would do it.

I'd recommend learning from my mishap and not bothering with this hassle on the front at all seeing as there is no real advantage. If you are determined to give it a shot, I'd recommend cleaning the pre-applied threadlocker off the stud first so that you can do a proper dry fit - then use Loctite Red to fix the stud in place.

cheers - time for a beer ...

NVRANUF

@ acadian_dad: Any pictures?

You are stacking washers to gain threaded portion of the stud? Hard to visualize why the need for spacing, sorry.

911rox

1gunner, his studs must be too long and its only the first 15-20mm that is threaded so the nut wouldn't tighten against the caliper....

NVRANUF

If that's the case, I'd be leary having the actual point of securement distanced from the caliper with washers or spacers.... Especially a front caliper!

But then I'm not an engineer!

911rox

Not an ideal solution but probably temporary till another solution can be found....

acadian_dad

I've drawn a rough sketch below (not to scale) of the situation I ended up with.



A bushing that should work is shown below (dims in mm) ... this is based on fact that 4x stacked M10 washers worked. The stack measured ~8mm thick.



I don't think its optimal ... but I don't see a hazard.

NVRANUF

Building on (or deviating from...) Porsche GT3 brake design and engineering is a ballsy move..... Hope you're right!

I'll stick with the stock bolt, it's tested and proven

savyboy

+1

I've had calipers off/on more frequently than 95% (probably 99%) of GT3 owners and have yet to have a problem with (reusing) the stock caliper bolts or damage to the carrier threads. With that said, I always clean the bolt and carrier threads with brake-clean spray before reassembling to remove grit and microscopic metal shavings and I always use a torque wrench when tightening.

acadian_dad

I'm not disagreeing completely but I recognize that the engineering tradeoffs that are considered in design include cost, frequency of service, commonality of components, etc. Not everything that Porsche does is perfect ... coolant lines, IMS, RMS ...

For a street car (which the GT3 is fundamentally), that rear set of pads is expected to be changed maybe 2-3 times in warranty period and maybe 10x in life ... vs. multiple times per weekend on a race car - or every other week for a frequently driven DE car. Those different requirements could result in different design choices.

I have no concerns replacing the pan-head bolt with a PMNA supplied stud/nut in and of itself - if the cup cars use studs, I think they will stand up to my abuse.

That said, I agree that the situation I find myself in with the fronts is NOT optimal - the part is not a direct replacement for my car. I would NOT recommend to anyone with the same car replacing the front bolts with studs since they are not required to be removed frequently.

The use of washers / bushing is just the lesser of evils for me at this point given that the studs are already in. Removing that threadlocked stud is more likely to cause damage than leaving it alone.

TRAKCAR

I threaded my rear on my '07GT3 and a caliper behing held on by your wheel is no fun.
Others all had to TimeSert the uprights eventually.

Not everyone is as precise as Savyboy and I recommend the studs if you track a lot!
It will be the first mod I do on my next RS!

acadian_dad

Well ... not much else to say about this ... I'm an idiot.

There's a very good reason why the stud that I installed for the front caliper was too long. It's because it was in fact the stud for the rear caliper ...
I realized this as I went to install the rear caliper stud and said to myself - well that's strange ... why do I only have 2 rear studs left and all 4 front studs left. Oh F___ !

I will properly dry fit the actual front stud tomorrow and let everyone know but from eyeballing the differences, it should work.

Please keep the laughter to a dull roar ...