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beware of over-torquing


redkow97

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Either the internet lied to me, or my OEM honda bolts are pieces of shit.

I was torquing my caliper bolts to the spec 22 ft.-lbs., and one of them snapped off in the fucking caliper. I should have known the bolt was twisting when the wrench wouldn't read beyond 15 ft.-lbs for multiple turns...

Anyway, I now have 1 caliper bolt that's in 2 pieces, and another that is literally thinner in the middle than it is on either end - the metal stretched from twisting.

Luckily only the calipers are threaded (not the forks), so it wasn't a huge pain in the ass to remove the bolt that broke.

I found a full replacement set on eBay for a reasonable price, but it won't ship in time for my race weekend. Calling local dealerships now... expecting to pay at least $4 per bolt, unless I can find them at home-depot!

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yeah, I'm not opposed to paying for my mistake (especially when it's an $8 mistake); it's the shipping I'm worried about.

Bike Bandit wants $3.80 per bolt and $7 to ship, but they may not arrive until 5/3. I'm racing 5/1.

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Sills Honda can get them for me by Thursday, which gives me that evening to drill them and put them on the bike :D

In the mean time, I am going to grab "backup" bolts at home depot so I can test-ride the bike, and not have the caliper sitting on a cinder-block (so it doesn't hang by the brake line)

Otherwise, I literally just need to re-wire my oil plug, and throw on the lower fairing (which I won't both with until after tech at the track).

thanks guys.

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I'd go to the local Fastenal branch or another specialty fastener warehouse. Glad it was a farily painless surgery to extract the broken bolt. My '97 YZF1000R had 5mm hex driven socket-head capscrews for the rotors and calipers and needed torqued about 20 ft-lbs, the hex bit loved to roll inside of those bolts.........but I replaced them with torx driven grade 8's as I took them in and out quite a bit for brake jobs -- think I gave a tick over $30 for all new hardware for both fronts and rear setups, but the torx bolts will allow for some major overtorque if you're not careful ;););)

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already had a similar offer from another member, but thanks. I think i'll be okay.

the service manual for 03/04 says 22 ft-lbs and for 05/06 says 33.

Not sure how 15 lbs wrecked the bolt, but given that these are safety wired anyway, I'm not even going to use the torque wrench on them anymore... decently tight with the 3/8 ratchet is plenty. probably 15-17 ft-lbs if I really try.

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Silly noob. Hope you get it going for this weekend. I plan on stoping up to watch some of the races.

Sunday weather looks like shit, so who knows if I'll actually race. spending $160 to go 70% in the rain sounds like no fun, and rain tires are NOT an option right now :(

I'm hoping to get an accurate enough forecast that I can at least get in one of the C class races on a dry track.

You know what bike to look for, but if I'm on track, look for expert plate #213. I'm supposed to meet up with my buddy Brad, and hopefully some others from ORDN.

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are you rk97 on wera? pretty sure i bantered you on the wera race school thread for a few posts lol sunday weather is a crapshoot at the moment. i just bought rain tires so hopefully the rain will push out to monday now that i did that...

i can't remember but did you already do the race school? get your transponder and all that good (expensive) stuff?

i'll be heading up saturday and pitting with steve (sjc). good luck to you and i hope to see you out there.

also i know this should probably go in the wera thread... if you do get taken out by another ballsy rider it will most likely be a fail for the day. However, Sean is pretty good to allow for extenuating circumstances. case in point, at the race in summit point, there was a PN who got taken out by a over-zealous rider bombing into T1 on lap 1. they failed him for the day because all the registration ladies look at is for a DNF or finish position to determine if you get your signature. i had happened to catch all this on video and the guy used my video to appeal and got the ruling overturned by sean.

like you said, it's the spirit of the rule and it's not a hard line pass/fail.

Edited by natedogg624
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Either the internet lied to me, or my OEM honda bolts are pieces of shit.

I was torquing my caliper bolts to the spec 22 ft.-lbs., and one of them snapped off in the fucking caliper. I should have known the bolt was twisting when the wrench wouldn't read beyond 15 ft.-lbs for multiple turns...

Anyway, I now have 1 caliper bolt that's in 2 pieces, and another that is literally thinner in the middle than it is on either end - the metal stretched from twisting.

Luckily only the calipers are threaded (not the forks), so it wasn't a huge pain in the ass to remove the bolt that broke.

I found a full replacement set on eBay for a reasonable price, but it won't ship in time for my race weekend. Calling local dealerships now... expecting to pay at least $4 per bolt, unless I can find them at home-depot!

is that a lot?

Megusta.png

...because different size fasteners have different torque specifications. A M6x1.0 SHCS for an engine cover won't have the same value as a M10x1.5 SHCS for a brake caliper.

Also' date=' the torque specs change, depending on the type of fastener, whether or not the threads are lubricated, etc...[/quote']

almost sounds like you know what you're talking about

troll.png

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I'm doubtful that aluminum fixtures can stretch a grade8 fastener to the breaking point, more than likely you'd pull the threads from the caliper before the bolt stretched to where it would shear - think most OE bolts are a grade 5? I may be wrong but they seemed softer than the 8's I upraded to back then

::edit:: Now that I think about it, did it shear at the head of the bolt? Or somewhere on the shank? It would make sense it could break at the head if over-torqued enough times but you're racing the bike right? Thats quite a bit of extra force against those bolts, may need to upgrade them all

Edited by Hellmutt
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Either the internet lied to me, or my OEM honda bolts are pieces of shit

Neither. Some monkey (probably one without a manual :D) previously german-torqued them, over did it, and necked the fastener. You already noticed that when you stretch the bolts, they get thinner, and with the reduced cross-sectional area, weaker.

the service manual for 03/04 says 22 ft-lbs and for 05/06 says 33.

This is correct. 05 moved to radial mount calipers.

Not sure how 15 lbs wrecked the bolt

See above.

but given that these are safety wired anyway, I'm not even going to use the torque wrench on them anymore... decently tight with the 3/8 ratchet is plenty. probably 15-17 ft-lbs if I really try.

And this is why I need to drill holes in my goddamn bike. It's a lowest-common-denominator catch-all. If the shit was put together right everytime it wouldn't fall apart.

/rant

Nothing personal Chris, just strokes a nerve as I've spent my last 50 hours of free time in the garage wrenching on something of questionable history.

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P.S. Safety wire isn't meant to hold things tight as much as it is a visual verification that something was properly torqued. While it may keep things from falling out, if a fastener has already loosened to the point that .025 wire is holding it in, the joint is compromised.

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