Brake caliper bolt replacement

[JZH]

On 4/20/2021 at 10:32 PM, DannoXYZ said:

From these:

 

https://www.boltdepot.com/fastener-information/Bolts/Metric-Recommended-Torque.aspx

https://applifast.com/wp-content/uploads/2017/07/Applifast_Conversion_Table-Torque.pdf

 

I get 40-55 lb*ft for similar strength to grade-8 bolt. Makes no sense unless Honda's using bottom-barrel bolts. 

 

Just replaced CV-axles on my Porsche last weekend. Looked up 8mm cheesehead bolt torque-specs and it was 33-36 lb*ft. Toyota and Porsche put out tech-bulletin to increase torque for head-bolts on their turbo models by +20-25% to alleviate headgasket issues.  Must be some bean-countre/engineer dictating design back in '80s.

 

Just helped friend replace rear-shock on his ST1300P,  Manual calls for replacing upper shock-mount bolt, but not bottom one. Both exact same diameter with exact same torque-spec... WTF??? Seems reversed as lower-bolt would face higher peak forces.

 

Honda doesn't say what grade these bolts are, but they do suggest they are not standard bolts by identifying them as "ALOC bolt/screw".  All of the ALOC bolts I've seen have a dry substance applied to them when new, which I suspect is a threadlock of some kind.  (However, being dry, possibly this does not significantly affect the torque reading.)  

 

At various times I have asked Honda to explain the true purpose/function of its "ALOC" fasteners, but I've never received any response that made sense.  I was probably asking the wrong people!

 

Ciao,

 

JZH

[Careca]

Ok .........so we all know how to use a torque wrench . Correct torque is good. 

 

However , like the OP I have re-used my bolts many times. Other than a titanium bolt I have never snapped a Honda bolt , ever. 

 

With titanium , which doesn't stretch like steel you need to reduce the quoted torque by 20 %  as titanium doesn't stretch like steel .

 

With regards to Honda bolts and in particular with any bolt that has thread lock on it. if you remove the bolt, you need to remove all the old thread lock off it and most importantly also tap the hole to get all the old thread lock out of it. Otherwise your bolt will seriously drag as you put it back in and can snap . Imagine how much thread lock is in that hole after 30 times of having thread lock applied every time someone put that bolt  back in .  If you haven't removed the previous thread lock you are just making things worse for that bolt. 

 

 

 

 

[DannoXYZ]

Yeah, depending upon grade, Ti bolts will have lower yield & ultimate strength limits than steel. I make sure Ti bolts are 6al/4va alloy to be similar to grade-8 steel bolts. Many are CP or 3/2.5 alloys which aren't good for structural use.

[Cogswell]

 

10 hours ago, JZH said:

 

Honda doesn't say what grade these bolts are, but they do suggest they are not standard bolts by identifying them as "ALOC bolt/screw".  All of the ALOC bolts I've seen have a dry substance applied to them when new, which I suspect is a threadlock of some kind.  (However, being dry, possibly this does not significantly affect the torque reading.)  

 

At various times I have asked Honda to explain the true purpose/function of its "ALOC" fasteners, but I've never received any response that made sense.  I was probably asking the wrong people!

 

Ciao,

 

JZH

 

I don't know of anyone that's ever gotten to the bottom of the "ALOC" acronym . . . The conventional wisdom seems to be that it means "Apply Loctite Or Crash".  

 

When I replace mine I use a white paint marker across the bolt and mounting boss as an assembly mark so I can easily see if they're backing out.