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Question on re-using caliper mounting bolts.

pyrophilus

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I need to replace my front wheel hub/bearing assembly.
I have all the parts (hub assy, new axel nut, dust cap).
I looked at the FSM, and it says to discard the caliper mounting bolts (Brembo).

I just called Ford dealer and they said the bolt is on backorder so 1 to 2 weeks if I order it.
I really was hoping to do the hub replacement this Friday (don't feel like driving a car that clunks every time I turn my wheel or hit a bump).

I know that the bolt is not to be re-used because of stress and I am guessing the torsional stress of mounting and unmounting Ă— 2 may be too much??

Are there folks here that re-use their caliper mounting bolts?

If I put on blue loctites (which I do anyway), would it be okay? I plan on ordering the bolts, so I am thinking of doing the hub job, and re-use the caliper bolts, and then just swapping the new bolts when they come in.

I know that when I used to ride Nissans, the dealer would often re-use the strut mounting nuts, so I would actually buy new ones and then swap them out afterwards. I was told, "re-using it once is probably okay..." by one of the techs. This is why I ended up doing my own struts after a few times.
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boB

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Some reasons why bolts should not be reused are: pre-applied threadlocker; torqued to yield; plating applied to give specific torque/stretch characteristics. Since we don't know Ford's reasons we are taking a chance by reusing the bolts. Can you get away with it for 2-3 weeks? "Probably" as the Nissan tech said. ;)


The best explanation I saw was on Fastenal's website: a bolt was torqued to 70 lb*ft for a clamp load of 9000 lb. To get the same clamp load on the 2nd tightening took 95 lb*ft, the 4th 145 lb*ft. That's enough to convince me to use new bolts.


There always exceptions to everything, I rebuilt a Jeep inline 6 cylinder head and the service manual noted that the bolts could be reused once (and to mark them so it was obvious). The big cast iron head weighed so much it probably didn't even need bolts. ;)
 

NoVaGT

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Google the part number, you should be able to find it and get it faster than 2 weeks.
 

K4fxd

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99% sure the reason is the thread locker. Just clean the threads real good and put some blue loc tite and call it a day.
 

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ctandc72

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In an application like your - it's the thread locker - the reason is labor for a dealer tech to have to clean the threads on the bolts, then correctly reapply the correct compound. Cheaper to just use new bolts. Same thing with driveshaft bolts.
 

D Bergstrom

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I swapped the calipers on my old 2017 GT and reused the original bolts, kind of cleaned them up a bit and added some blue thread locker. Worked just fine for 4,000 miles prior to trading the car in. Also swapped the calipers on my new 2020 GT, reused the original bolts also, this time I just reinstalled them. Just checked them a week or so ago after 1,000 miles, no issues.

Doug
 
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pyrophilus

pyrophilus

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Thank you to all of you for the great replies. I have a 4 day weekend and wife wants to drive up to MA for the weekend. I would rather not take her MDX... and I got my 13 year old to want to take a video and he said he'd like to post-process it and have me put it up on youtube. I was kinda looking forward to working with my kid on the car, so...

I have all new axel nut and even the dust cover, so I will go ahead and do the job on Friday, and use my dremel and carbon steel wheel to clean out the threads of caliper bolts and use new blue thread lock. Since they are caliper bolts, I think I will be okay for a few days (probably fine until next time I remove it, but...) and I'll put in new bolts.

Thanks again for the replies. It was very informative, especially the clamp load and the 2nd and 3rd tightening, and the clamp load vs overcoming friction.

I actually asked to see if other people refused boots and have not had bad issues (which I got answers for), but I loved the analysis. This is why I love this forum. You guys are awesome.
 

DougS550

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I need to replace my front wheel hub/bearing assembly.
I have all the parts (hub assy, new axel nut, dust cap).
I looked at the FSM, and it says to discard the caliper mounting bolts (Brembo).

I just called Ford dealer and they said the bolt is on backorder so 1 to 2 weeks if I order it.
I really was hoping to do the hub replacement this Friday (don't feel like driving a car that clunks every time I turn my wheel or hit a bump).

I know that the bolt is not to be re-used because of stress and I am guessing the torsional stress of mounting and unmounting Ă— 2 may be too much??

Are there folks here that re-use their caliper mounting bolts?

If I put on blue loctites (which I do anyway), would it be okay? I plan on ordering the bolts, so I am thinking of doing the hub job, and re-use the caliper bolts, and then just swapping the new bolts when they come in.

I know that when I used to ride Nissans, the dealer would often re-use the strut mounting nuts, so I would actually buy new ones and then swap them out afterwards. I was told, "re-using it once is probably okay..." by one of the techs. This is why I ended up doing my own struts after a few times.
I've noticed in their manuals, every bolt I roved from the front to the rear, calipers, radius arms, vertical links, lower control arms etc, the manual noted to disguard old ones and use new ones. None of them were one time use Special bolts. Go figure.
 

ORRadtech

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I've done my own brakes since before disk brakes were common. The first time was when I "helped" my dad at 8 or 9 years old. In all that time I've replaced caliper mounting bolts maybe twice. And even then it wasn't simply because they weren't new.
I have never, ever had an issue reusing them.
In fact, it never even occurred to me that they might need to be replaced so this thread has definitely been enlightening. When I do mine later this summer I may replace them or I might just clean them really well. I think I'll be comfortable doing either.
 

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thunderstrike

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I've reused bolts many times. One thing about blue loctite is it's hard to unscrew and screw back on due to dried loctite, so don't put too much on. As long as you don't way over torque them, they'll provide good service life. These bolts are designed to stay on with proper torque.

When back ordered bolts are delivered, you may feel free to replace them.
 

ICU812

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I have yet to see a caliper bolt break.
I am sure the reason for wanting replacement is the fact that they are high performance brakes, and Ford has no way of knowing if you drive your car normally, or autocross, track day it allot, putting a lot of heat into the bolts. heat cycles kill the strength , That said.
If you don't track day the car, or drive it like you stole it. you should be fine, after cleaning the threads, and adding high temp, thread locker.
If you have put a lot of heat into the brakes, and use them heavy handedly. I would replace the bolts, ASAP. but you will be fine for a week or two, till the new ones show up.
Remember they wrote the advice with the understanding that a person bought the car with heavy duty track style brakes, to use them hard. Most owners don't drive in away that really puts the heat into them, that they were designed for. but ford has to ASSUME you do.
I have never seen a caliper bolt break in use. seen them break when someone over torqued them, or seized , but not from use. I have seen rotors crack and shatter like glass.
 

K4fxd

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I am sure the reason for wanting replacement is the fact that they are high performance brakes, and Ford has no way of knowing if you drive your car normally, or autocross, track day it allot, putting a lot of heat into the bolts. heat cycles kill the strength
When I had dedicated race cars we did not change caliper bolts.
 

shogun32

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GM was "helpful" enough to use torque-yield bolts on the Camaro calipers so they are a literal once and done. Ford was much smarter in this regard. Use a wire-wheel or a pick. Ideally you'd have tap and die set but it's not a biggie.

I'm not so sure I would do brakes/hub right before a long road trip though.
 

codereddew

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if you clean the loctite off properly, i don’t think there’s anything wrong with reusing the caliper bolts.

Hell, probably not the greatest idea, but I’ve even reused the lower strut bolts more than once and have driven several thousand miles without issues lol
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