Brake caliper bolt issues

[356Guy]

Looks like trouble...I'm doing the rear brakes and the top bolt has picked up. It turned about 1/2 turn out and stopped. I can now turn it about 1/8th turn either way but that is it. I left penetrant on it tonight (that never works) and will get the acetylene torch on the carrier tomorrow and hope some heat helps. Any other ideas?

[356Guy]

I put a little heat to the carrier with the torch and struck the bolt a few times with a hammer. It came out with difficulty using an 18" snipe. The carrier will need a helicoil but at least I can save it. I also found that the rotor was loose because both screws had been sheared off at some time. Its got the same Textar pads that I bought. Are these OEM?

[Burg Boxster]

Wheel bolts and the wheel are what really holds rotor hat tight against hub.

Set screw basically keeps rotor/hat in place / aligned when they are not present. Thus why when replacing hand tight is the torque spec.

Textar pads are fine.

Might try running tap thru carrier first to clean up threads instead of immediately jumping to helicoil. Especially since you were able to extract caliper bolt w/ just some heat and penetrating oil. Threads actually look decent all things considered... Tap could be right fix and obviously save you a ton of time.

Good luck

[356Guy]

I'll run the tap through but the threads didn't look so good. I have to order some bolts and screws now.

[PaulE]

Originally Posted by 356Guy

I'll run the tap through but the threads didn't look so good. I have to order some bolts and screws now.

FWIW Porsche recommends using new mounting bolts every time the caliper is removed and reinstalled. They are about $5 each for OEM and it made sense for me to do it when I changed my front rotors and pads. I don't know how the experts feel about that but would be curious to hear others thoughts on it.

[BYprodriver]

Originally Posted by PaulE

FWIW Porsche recommends using new mounting bolts every time the caliper is removed and reinstalled. They are about $5 each for OEM and it made sense for me to do it when I changed my front rotors and pads. I don't know how the experts feel about that but would be curious to hear others thoughts on it.

I assume it's due to deterioration of the hex head & thread coating. I remove the bolts with the best tool available, (Snap On) & coat threads with anti-seize for reassembly, I have the OE bolts in my 2000 Box. ( living in So. CA helps alot, YMMV)

[tommy583]

I snapped a bolt when doing the front brakes a few years ago. I had to get a hub from woody.

[356Guy]

I was worried about breaking the bolt so when it stopped moving with the short snipe on it went to the torch. It would be a pia to have to remove the rear carrier. I ran the tap through the holes today. They all got quite a bit tighter near the bottom threads. This is where the problem started.

[lkchris]

Originally Posted by PaulE

FWIW Porsche recommends using new mounting bolts every time the caliper is removed and reinstalled. They are about $5 each for OEM and it made sense for me to do it when I changed my front rotors and pads. I don't know how the experts feel about that but would be curious to hear others thoughts on it.

Porsche are the experts ... there are no other.

BTW, there’s a major difference between recommendation and specification ... Porsche specifies.

I’d really think these screws stretch when torqued to specification. In many applications this is indeed considered a one-time event.

Bolts are for putting nuts on ... when you don’t, it’s a screw.

[Gilles]

Originally Posted by lkchris

Bolts are for putting nuts on ... when you don’t, it’s a screw.

Please stop screwing up... LOL

sorry, could not resist

[Burg Boxster]

Originally Posted by lkchris

Porsche are the experts ... there are no other.

BTW, there’s a major difference between recommendation and specification ... Porsche specifies.

I’d really think these screws stretch when torqued to specification. In many applications this is indeed considered a one-time event.

Bolts are for putting nuts on ... when you don’t, it’s a screw.

All bolts are screws but not all screws are bolts is more meaningful than all bourbon is whiskey but not all whiskey is bourbon...

I leave you to inform Porsche all the corrections needed in owner manuals, part catalogs and workshop manuals re: bolt vs screw.

Good luck

[PaulE]

My bad on the recommend vs. specifies. I thought it was due to stretching when torqueing. I always thought a screw was something that required a flat or Phillips screw driver! Now, is a stud a screw or a bolt, or is it just a stud?

[356Guy]

Luckily the dealer has the bolts in stock so I can pick them up Friday. $9.75 Cdn ea!

[356Guy]

Brakes done now with a total flush and all is well. I just don't get to break them in until April! As usual there are extra parts as I didn't need the new sensors. I ended up not reusing the old anti-squeal pads and applying Permatex blue anti-squeal liquid. Hopefully that does the job.

[jakeru]

Using some aluminum-grade anti-seize on those caliper mounting screw threads prevents this thread galling problem from happening. I've had really good luck with the aluminum paste formulation anti-seize for bolts like these - Permatex #81343 works great, and comes in an easy to use small tube which doesn't seem to evaporate, or allow the oil to separate from the solids.

Going for a light, even coating on the threads (so it looks like in the photo below) keeps things neat and tidy:
How to Properly Use Anti-Seize

[356Guy]

I used a very light coating of anti seize on the first few threads as that is where the problem started. Seeing as the pads were original (I think) with 110k (60k miles) I doubt I will ever change them again

ps my Motive bleeder is a wonderful tool