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Wilwood Powerlite torque setting
JMW - 27/4/15 at 04:47 PM

Anyone got any idea of the torque setting for the two M10 Allen bolts that attach the Powerlite caliper to the bracket which in turn attaches it to the upright?

I know what I use for the bracket to the upright, I just don't know the caliper to the bracket number.

RallyDesign tell me the bracket is HE30 alloy but couldn't tell me the torque setting.

ashg - 28/4/15 at 02:57 AM

ft worked pretty well for me

JMW - 28/4/15 at 07:06 AM

M10 into HE30 torque setting?

Anyone?

thefreak - 28/4/15 at 02:44 PM

Tight with a dab of threadlock on the thread should be enough

rodgling - 28/4/15 at 03:54 PM

Depends what grade of bolt you are using. Any of the various on-line bolt torque calculators should be able to calculate a precise number for you. This should do the job:

http://www.futek.com/boltcalc.aspx

Are you bolting into a threaded hole in the bracket or using a nut on the other side? If the former then you might want to ideally helicoil the bracket for extra strength.

JMW - 28/4/15 at 04:39 PM

quote:
Originally posted by rodgling
Depends what grade of bolt you are using. Any of the various on-line bolt torque calculators should be able to calculate a precise number for you. This should do the job:

http://www.futek.com/boltcalc.aspx

Are you bolting into a threaded hole in the bracket or using a nut on the other side? If the former then you might want to ideally helicoil the bracket for extra strength.


Very useful website, thanks for that.

To answer your questions, the Allen bolt is 12.9 (actually stamped) and the HE30 bracket is threaded. i.e. no nut.

rodgling - 28/4/15 at 09:28 PM

That website recommends 29 ft-lb with a max of 38 ft-lb assuming 15mm of thread engagement and bolt pitch of 1.5mm. Interestingly these values don't change for a grade 8.8 bolt, i.e. the weak link is the aluminium.

As I understand it this means the bolt won't be properly stretched so is more likely to work loose, so be sure to use a locking mechanism (maybe threadlock if it can withstand the temperature).

Hence my suggestion of helicoiling the bracket if you want to make it a bit more robust (this is what I did for the calliper brackets I made). I can't remember how you calculate the torque values for a helicoil in aluminium though, IIRC it's something like 80% less than you'd use into steel (i.e. recommended value of around 41 ft-lb in this case).

JMW - 28/4/15 at 10:04 PM

I used the website but I couldn't specify 12.9, so used grade 8 instead and couldn't specify HE30 so picked the weakest ally from the dropdown. I got 33 ft/lbs. How did you get to your figures?

I am reluctant to re-engineer Wilwood's solution, I reckon they know more about brakes than I do. I certainly intend to use a threadlocker, so I am not worried about it coming undone, but do want to implement the correct clamping force.

I tried to fill in one of Wilwoods on-line query forms to ask them this question but couldn't get past their edit checks on the phone number field, not only did it expect a Stateside number but wanted some alpha State code that I couldn't fathom out, and it didn't like "CA", as a test.