Brake Caliper Bolts

[Deputy347k9]

Originally Posted by Russell James

Any bolt where the tq spec is given in degrees past a tq is a TTY bolt.

TTY is a more consistent tq when sealants, lubes, locking agents... are used. Those things can throw the tq reading way off, so to get a consistent clamp and bolt stretch you do it in degrees. The bold stretching will maintain a stronger clamp force.

It can only be done once though, the second stretch to that length will not have the same clamping force. It's been fatigued and will just keep stretching instead of clamping. If someone successfully re-used a TTY bolt, they probably didn't stretch it the second time and it is not tq'd properly.

At a drag strip near me there was a critical head injury, someone got hit by a harmonic balancer at the starting line. As the lawsuits were flying, one of the defendants had a failure analysis done. End result... a TTY balancer bolt had been reused and snapped. The shop that did the last motor refresh was in a world of hurt. Any time negligence is involved, it can become $$$$$$$ and even criminal.

If you see anyone re-using a TTY bolt, you are looking at an idiot. Harsh, but fact. They teach that sht in HS auto shop, let alone a tech degree, state certification tests....

Thank you very much for the "upfront and clear explanation" of the TTY bolts. I couldn't agree more. When I had my Brembo calipers powder coated I did replace all 8 caliper bolts. Matter of fact I purchased 8 extras to keep on hand just incase I might need them.

Looking back on my receipt dated September 21, 2017 I paid the following; 8 front caliper bolts #11570788, list was $4.48 each my cost was $3.36 each. For the rears list coast was $3.48 each and my cost $2.61.... So... your insurance policy will cost you $23.88 plus tax each time you change them. CHEAP INSURANCE!

I find it amazing as to how many people reuse the TTY bolts, not just on the calipers but also the head bolts and harmonic balancers. The "potential" dangers and liabilities is not worth the $23.88 insurance policy.

[havelegs]

I replaced mine.

[VRZL113]

Originally Posted by ZMEnow

His tag says SS not ZL1, if that's the case its not the same brembo.

My bad... we are in the ZL1 section, so I didn't even look to see what he drives.

In any case, my post is still helpful to ZL1 owners who need the part #.

[ZMEnow]

Originally Posted by VRZL113

My bad... we are in the ZL1 section, so I didn't even look to see what he drives.

In any case, my post is still helpful to ZL1 owners who need the part #.

You are all good... It's no longer just a ZL1 forum anymore, it gets trolled quite frequently..

[Annatar]

Okay so reading this thread here, I'm at a loss:

when I punch in the GM part numbers on this thread, the newgmparts.com web site explicitly says that those do not fit my 2013 Camaro ZL1. What gives?

I reused my caliper bolts, and torqued my front caliper mounting bolts to 200 Nm (147 ft lb), rear to 120 Nm (88.5 ft lb). Have I majorly screwed myself?

[z28lt1]

Originally Posted by Annatar

Okay so reading this thread here, I'm at a loss:

when I punch in the GM part numbers on this thread, the newgmparts.com web site explicitly says that those do not fit my 2013 Camaro ZL1. What gives?

I reused my caliper bolts, and torqued my front caliper mounting bolts to 200 Nm (147 ft lb), rear to 120 Nm (88.5 ft lb). Have I majorly screwed myself?

Something is weird with the parts catalog. I just checked and in shows that that the bolts are good for 2012 Zl1s and 2015 Zl1s. There's nothing special about 2013, 2014 that they wouldn't fit those either, so I strongly suspect its just an error in the catalog causing it to not see 2013 and 14 as compatible.


The answer to if you major screwed yourself reusing bolts depends upon if you want an official answer, or an anecdotal answer.



The official answer is that TTY bolts should only be used once, and if you reused them you have stretched them twice primarily meaning they aren't torqued properly likely and the bolts are weaker and closer to a failure. So don't reuse them.


The anecdotal answer is that tons of people have reused them (many will put some loctite or something on it) and I can't recall anyone with a brake caliper bolt failure. When I did my brakes the last time, I called like 5 dealers in the area and not a single dealer had any bolts in stock. I'm certain all of them would replace my rotors if I let them, so that tells you what many of the dealers (incorrectly) do.



So, the best bet is to replace them, it isn't that expensive and is the right thing. That said since you already didn't replace them, I wouldn't stress about it. Due to circumstance (not having any available when needed) I've reused a few times. I do my best to make sure they are replaced at least every other time, so they are reused at most once (which properly is once too many) although I know people who have reused TTY caliper bolts many times.

[Annatar]

Originally Posted by z28lt1

Something is weird with the parts catalog. I just checked and in shows that that the bolts are good for 2012 Zl1s and 2015 Zl1s. There's nothing special about 2013, 2014 that they wouldn't fit those either, so I strongly suspect its just an error in the catalog causing it to not see 2013 and 14 as compatible.

They even looked correct, which further added to my confusion.

So is the following correct: front caliper bolts are GM part number 11570788?

What is the rear caliper bolt part number?

Are there corresponding AC Delco part numbers?

The answer to if you major screwed yourself reusing bolts depends upon if you want an official answer, or an anecdotal answer.



The official answer is that TTY bolts should only be used once, and if you reused them you have stretched them twice primarily meaning they aren't torqued properly likely and the bolts are weaker and closer to a failure. So don't reuse them.

As an engineer, I go a priori for an official answer, because I trust my colleagues know what they are doing when they write the specifications and the manuals (bearing in mind that sometimes we have to revise both due to additional factors and / or requirements).

With that written, the nature of the bolts and their intended application, what I do not understand is how I was even able to torque them that high without them snapping; it boggles the mind.

So, the best bet is to replace them, it isn't that expensive and is the right thing. That said since you already didn't replace them, I wouldn't stress about it. Due to circumstance (not having any available when needed) I've reused a few times. I do my best to make sure they are replaced at least every other time, so they are reused at most once (which properly is once too many) although I know people who have reused TTY caliper bolts many times.

I did not order them because I do not have the service manual, so I simply did not know; if I knew the GM part number of the service manual, I would order it as well.

How much torque is specified in the service manual for the front caliper bolts?

Finally, I want to thank you kindly for your thoughtful answer.

[z28lt1]

Originally Posted by Annatar

They even looked correct, which further added to my confusion.

So is the following correct: front caliper bolts are GM part number 11570788?

What is the rear caliper bolt part number?

Are there corresponding AC Delco part numbers?
As an engineer, I go a priori for an official answer, because I trust my colleagues know what they are doing when they write the specifications and the manuals (bearing in mind that sometimes we have to revise both due to additional factors and / or requirements).

With that written, the nature of the bolts and their intended application, what I do not understand is how I was even able to torque them that high without them snapping; it boggles the mind.I did not order them because I do not have the service manual, so I simply did not know; if I knew the GM part number of the service manual, I would order it as well.

How much torque is specified in the service manual for the front caliper bolts?

Finally, I want to thank you kindly for your thoughtful answer.

You can find most of these answers earlier in this thread.
Front bolts: 11570788

Rear: 11515781


I don't know if there is an AC Delco cross reference.


It has been posted o the forums several places that torque is 30 foot pounds and then 90 degrees (works for first time only). I haven't verified this elsewhere.



Helm makes the service manuals for GM. For your 2013, service manuals should be: https://www.helminc.com/helm/product...13F&itemtype=N


Not sure if a dealer would have these to sell. I believe for 2013 it is 4 books.


Finally, while the bolts are meant to be used once, as noted, I wouldn't expect them to totally snap the second time (for brakes calipers, not for motors or other things), but they will be weaker, and with them stretched, possible less holding force and more likely to come loose. They are still high grade bolts, just now stretched.

[Annatar]

I broke off the front left caliper bleeder valve bolt when I was trying to do the brake fluid flush, since it has never been done before.

Does anyone know what the GM / AC Delco / Brembo part numbers are for the the front and rear bleeder valve bolts?

[larry_g]

Originally Posted by Annatar

I broke off the front left caliper bleeder valve bolt when I was trying to do the brake fluid flush, since it has never been done before.

Does anyone know what the GM / AC Delco / Brembo part numbers are for the the front and rear bleeder valve bolts?

Good luck getting the broken part of the bleeder out of the caliper. I replaced all of mine with speedbleeders.



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[gtstorey]

Rockauto list genuine GM plus others.
https://www.rockauto.com/en/catalog/...e+bleeder,1676

[ZMEnow]

Originally Posted by Annatar

I broke off the front left caliper bleeder valve bolt when I was trying to do the brake fluid flush, since it has never been done before.

Does anyone know what the GM / AC Delco / Brembo part numbers are for the the front and rear bleeder valve bolts?

Don't over tighten, also if you have air handy blowout the top of the bleeder and around the side to get all the excess brake fluid out then just hit the bleeder valve with WD40 and you will be good to go next time.

[Annatar]

Originally Posted by larry_g

Good luck getting the broken part of the bleeder out of the caliper.

Thank you kindly; I'll need it.

I bought a set of bolt extractor bits. My plan is obtain replacement bleeder valves first, just in case any other ones decide to twist off like this one did.

Then I'll drain the brake fluid out of the system because I plan to use a heat gun to heat up the brake caliper and the bleeder valve to 900 degrees Celsius, and for that, the brake fluid has to be drained first so I don't cook it while it's in the system.

Once that's done, I will tap the bleeder valve with an extractor bit and hopefully I will be able to extract it.

I replaced all of mine with speedbleeders.

Never heard of them; I will research them.

[Annatar]

Originally Posted by gtstorey

Rockauto list genuine GM plus others.
https://www.rockauto.com/en/catalog/...e+bleeder,1676

Where I used to live we only had "AutoZone" and "Advance Auto Parts", so this vendor was unknown to me hitherto. It looks like they ship internationally as well, which is what I require.

The only issue I see is a cosmetic one, in that their valves are Silver while mine are Black. I wonder whether it would be a good idea to coat mine with some satin Black once it's in, taped around so the paint doesn't get into the threads?

The really dumb thing is these are Brembo bleeder valves and I live in Europe, if only I knew the Brembo part number I wouldn't have to order something made in Europe from the United States... I spent two hours trying to find the Brembo part number but so far no joy.

Originally Posted by ZMEnow

Don't over tighten,

Brembo painted over the bleeder valve and the caliper after they assembled it and it all baked in together, so I broke the bleeder valve off while trying to loosen it, can you believe that nonsense?

also if you have air handy blowout the top of the bleeder and around the side to get all the excess brake fluid out then just hit the bleeder valve with WD40 and you will be good to go next time.

I have a compressor, WD-40 and I will also have a vacuum cleaner handy. That's a good idea, I'll try your method first before I go for the heat gun.