mdrums

I just had my calipers off the car to replace the rubber dust shields and rotors. The shop re-used the caliper bolts. I've heard that these are a 1 time use bolt...anyone shed some light on this for me?

Car is a 09 Carrera S. thanks!

CWhaley

The thought behind replacing the bolts is: You torque them and place the bolt into a FULL Tension condition by stretching them to the required Torque value. Also, they are intended to have a locking type coating applied from the factory.
Few people really ever replace them unless they become damaged... Just apply a little thread locker on them and re-torque as specified.

Now I am sure this will stir up a TON of controversy.

Gus F

Yes, I understand that it is best to replace them every time since they stretch.
I have skip that step a few times already and they have work just fine, but now that you mentioned I'll order a set to replace them on the next pads change.

Asquared

See this thread for a long discussion (much of which has to do with failure of the threads in the housing, not the bold itself), but there is a lot of discussion that the bolts should be replaced every time.

savyboy

These are not torque to yield bolts. They may be reused but be careful to clean the threads both on the bolt and inside the carrier. I use my Sprayaway glass cleaner and a shop towel to clean both sets of threads and install dry and clean. Also very important to use a torque wrench when tightening, overtorque is what strips those aluminum carrier threads.

On/off about 10 times on my RS with no problem so far.

CWhaley

Keep in mind that this referenced thread is really looking at the failure rate from Fatigue (repeated force of placing a bolt into torque on the threads) & thermal heat exposure. What really failed in these situations were the tapped holes threads. A insert will increase the shear strength of the existing hole.

While these bolts are not "True Yield" bolts (when you place enough toque to the point of the materials yield point~before breaking). You are placing torque on them which creates a long term fatigue situation. Still, not enough that warrants replacement of the bolts.

kush07

There's not a shop I know that replaces them everytime. I'd give it few changes until it starts to keep you up at night. More importantly, I would NOT use a thread lock on these. I think you'd do some damage to the aluminum uprights if so. As mentioned, make sure threads are clean when replacing. Uprights get stripped all the time.

CWhaley

The Thread locker WILL NOT damage the threaded holes! I did not say PUT THREAD LOCKER 272 (which takes 500 deg F to get off). Damage to the uprights occurs from OVER torque conditions of the Caliper bolts and placing the cast aluminum thread features into shear!