Hub and Caliper bolts - One time use bolts?

[smokinscooters]

Agreed. I spent $20 on new hub bolts with my local Ford dealer. They're arriving in a couple of days.

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[dpAtlanta]

But even stretch to Yield Bolts can be reused after passing a thorough inspection.

You have my curiosity on this one... how do you do this?
Not being a wise-ass... I am actually curious.

 

[DougS550]

You have my curiosity on this one... how do you do this?
Not being a wise-ass... I am actually curious.

For me, All Engine TTY Bolts are replaced after removal, IE connecting Rod, Cam Bearing caps, Crank Journal, cylinder head ETC. I Always replace them after removal.
As for my Brake caliper bolts, I inspect the threads for stretch and mic the center section for Yielding. If they pass my inspection, I clean the threads and then reinstall with blue medium loctite and torque. As far as my Suspections TTY Bolts, I actually replaced them all when I upgraded my suspension parts, Vertical links, Toe Rods
camber links, LCA, Rear Shocks, rear K Frame, IRS Cradle support, Front Radius arm bolts ETC, I replaced them.
But that's just me. If anyone who does not feel safe after identifying a bolt is an actual TTY bolts feels uncomfortable with their reuces, then they should replace them for they are relatively cheap insurance to say the least.

https://www.google.com/search?q=how...#fpstate=ive&vld=cid:6064577f,vid:H62kDEbYCnU

 

[Tonymustang302]

Check out Caliperfection which allows you to replace the bolts with studs which don't need replacing.

GT350 Mustang Caliper Studs - Caliperfexion

I highly recommend!

this.

caliper bolts no
hub bolts i reused mine with 50+ tough track days on em and still good

 

[dpAtlanta]

As for my Brake caliper bolts, I inspect the threads for stretch and mic the center section for Yielding. If they pass my inspection

Thanks Doug... I was curious as to what is being done to verify.
The reason I ask is that the Engineering Lab I work at routinely does metallurgical and NDT testing on automotive and aircraft components. We have used Tensile testers to reach the yield point plus 1-2 psi over yield, then asked to determine if dimensional differences could be non-destructively determined (Elongation, necking, crack inspection via MT, UT & PT and optical microscopy).
The answer was no.
We could however see a difference if we sectioned the fastener, mounted and polished the sectioned piece, etched the polished surface, and compared the grain structure to a non-tested fastener. Micro-hardness also showed strain hardening across the sectioned surface.
Once the yield point is reached and exceeded even barely, the structural integrity is compromised.
The fasteners we tested were definitely "Torque to Yield" fasteners... that was the purpose of our testing.
That being said, I have ZERO first hand knowledge if the caliper bolts are actually torque to yield... I did no research and went with Caliperfection studs.
If they are not, your method is spot on.... elongation or necking = replacement.

Good Stuff...!!!!

 

[Optimum Performance]

Keep in mind the hub really does not have much thread on it. Pretty sure the threads in the hub would fail first. It's maybe a diameter deep.

 

[WildHorse]

Holy lol. Reuse the caliper bolts. you'll be fine.
FORD says buy new ones cause they're in the
business of making money. All the factory bolts
had to pass SAE tests. They won't fail unless YOU
make em fail.

 

[kgschrader]

That being said, I have ZERO first hand knowledge if the caliper bolts are actually torque to yield... I did no research and went with Caliperfection studs.

I struggle with this concept of torque to yield on the caliper bolts. They are screwed into aluminum hubs, right?...

I have the studs and like them. Continuously screwing bolts into aluminum makes me nervous. Too easy to gall the threads; even strip them. Also, changing pads is easy.

FWIW

 

[dpAtlanta]

I struggle with this concept of torque to yield on the caliper bolts. They are screwed into aluminum hubs, right?...

I have the studs and like them. Continuously screwing bolts into aluminum makes me nervous. Too easy to gall the threads; even strip them. Also, changing pads is easy.

FWIW

That’s why I said what I said… I have Zero first hand knowledge of the technical details of this fastener connection.
You make a great point…. If the steel torque to yield fastener is being joined to an aluminum female receptacle, then things are going to change.

 

[DougS550]

Thanks Doug... I was curious as to what is being done to verify.
The reason I ask is that the Engineering Lab I work at routinely does metallurgical and NDT testing on automotive and aircraft components. We have used Tensile testers to reach the yield point plus 1-2 psi over yield, then asked to determine if dimensional differences could be non-destructively determined (Elongation, necking, crack inspection via MT, UT & PT and optical microscopy).
The answer was no.
We could however see a difference if we sectioned the fastener, mounted and polished the sectioned piece, etched the polished surface, and compared the grain structure to a non-tested fastener. Micro-hardness also showed strain hardening across the sectioned surface.
Once the yield point is reached and exceeded even barely, the structural integrity is compromised.
The fasteners we tested were definitely "Torque to Yield" fasteners... that was the purpose of our testing.
That being said, I have ZERO first hand knowledge if the caliper bolts are actually torque to yield... I did no research and went with Caliperfection studs.
If they are not, your method is spot on.... elongation or necking = replacement.

Good Stuff...!!!!

I think the calibrated studs are a good idea for people who remove their brake calipers regularly. As far as TTY bolts, once a bolt has yielded/stretched, they cannot rubber band back to their original specs. If the bolt shaft, threaded area are micrometered, and their is no noted differences, in the measurements, which would tell you if the bolt have gone through deformation. But again, bolts are relatively cheap.

 

[dpAtlanta]

I have no idea on what a “calibrated stud” is……..???

 

[Evolvd]

I don’t know why we’re still discussing TTY bolts when the bolts in question aren’t TTY

 

[txgt]

I have no idea on what a “calibrated stud” is……..???

That’s what my wife calls me on date night.

 

[smokinscooters]

Another stupid question. Anyone know what size socket I need to remove/install the hub carrier bolts?

 

[K4fxd]

That’s what my wife calls me on date night.

She told me she calls you quick draw.



Sorry couldn't resist.

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