Backhoe Torque values 448 Backhoe Adapter Lubed or Dry

[satu]

Hello from Maine. I'm new to Tractorbynet, but have enjoyed frequent visits getting educated from the collective wisdom. Recently purchased a 2009 Deere 4120 with an assortment of attachments and only 200 hours. Loving it. So here's my issue.... bought a used 448 backhoe with the rockshaft adapter plates. Went to Fastenal and bought assorted 10.9 hardened metric fasteners with hardened washers, etc.
Today, while attaching the backhoe adapters, I attempted to torque a M14 x 60 fastener to the specified torque of 158 ft/lbs. The fastener cracked. My first thought was to suspect an inferior fastener. After some thought and a Google search, my revised thinking is that Deere Manuals specify torque values for dry wrenching.
Does anyone out there know this to be true, and if so, what percentage derate would be appropriate to compensate for a lubed fastener.
Thanks in advance to shared thoughts.

 

[Reg]

Hello from Maine. I'm new to Tractorbynet, but have enjoyed frequent visits getting educated from the collective wisdom. Recently purchased a 2009 Deere 4120 with an assortment of attachments and only 200 hours. Loving it. So here's my issue.... bought a used 448 backhoe with the rockshaft adapter plates. Went to Fastenal and bought assorted 10.9 hardened metric fasteners with hardened washers, etc.
Today, while attaching the backhoe adapters, I attempted to torque a M14 x 60 fastener to the specified torque of 158 ft/lbs. The fastener cracked. My first thought was to suspect an inferior fastener. After some thought and a Google search, my revised thinking is that Deere Manuals specify torque values for dry wrenching.
Does anyone out there know this to be true, and if so, what percentage derate would be appropriate to compensate for a lubed fastener.
Thanks in advance to shared thoughts.

After MANY years of just "socking everything up as tight as possible, except the little ones" I now follow tables (mostly).
I always lube threads, more for corrosion prevention than torquing, but use the dry threads torque.

IOW, I think it doesn't matter a D*M.
Oh yeah, there IS some nonsense about bolt stretch - theoreticians will flame me for ignoring that - OK, sue me.
Suffice to say that I don't break bolts or have nuts rattling loose.

BTW, I am fairly sure that the 448 is in fact an Amerequip 8600 (which I have on my smallest tractor).
I assembled mine without a torque wrench, M14 are fairly hefty so I just threw all my aged 187 lbs at 'em (-:
Again, it prolly don't matter a D*M

 

[Cidertom]

Below is some values of lub vs dry. One item that has caused grief on these is stripping the holes on the tractor.

class 10.9 IN FT POUNDS
size, dry, lubed
M8,30,21
M10,59,45
M12,97,76
M14,148,112

Use 80% of value when into taped aluminum.

I know there is a difference between these and the install manual.

 

[Zebrafive]

My Deere Manual list both lubed and dry torque values.

M14 class 10.9 dry 165 lb-ft and lubed 130 lb-ft.

Maybe you should have used Class 12.9.

M14 class 12.9 dry 190 lb-ft and lubed 15o lb-ft.

 

[satu]

My Deere Manual list both lubed and dry torque values.

M14 class 10.9 dry 165 lb-ft and lubed 130 lb-ft.

Maybe you should have used Class 12.9.

M14 class 12.9 dry 190 lb-ft and lubed 15o lb-ft.

I think you're right. Deere specified torquing the M14 x 60 at 158 ft/lbs. That would need to be a dry torque for the 10.9.

The thing that confused me was successfully torquing three of the four M14's to the specified value before getting into trouble. I removed one of the M14 torqued screws, placed it into the location where I'd cracked the forth screw. This time I stretched what was assumed to be a good screw. Hmmm.

The Deere Rockshaft Adapter parts list doesn't specify fastner hardness, but it seems reasonable to conclude that after breaking 1 screw and stretching another, I need to use the lubed torque of 130 or purchase 12.9 screws.

Thanks for your help.