On Sep 11, 9:50 pm, Doc > wrote:
> Just pondering the 9 ft/lbs specified for the rear seal housing on my
> Cressida per the factory manual. How are bolt torque numbers
> determined?

Basically it is a specification that has been determined by past
testing and documentation of the given fastener type plus engineering
consideration of the assembly parts in question. The two most
important things regarding the fastener are 1) it must not break/strip
threads at this torque value and 2) it must not back out from lack of
tension. The makeup of the parts and their intended duty modify this
equation as well.

In the case of a final assembly, lots of data is reviewed before
assigning a value to a fastener. Machining and material spec data
publications are used by design engineers as a baseline towards
engineering their specific requirements.

Toyota MDT in MO