I think the answer lies in the designer's desire to spread the braking
forces out over a wider area. During heavy braking, there is an enormous
amount of reaction torque on those threads which distribute the force to the
a-arm. Without the threads, that force would be concentrated at a single
point and a thrust bearing would be required (this would then become the
premature failure-point, instead of the threads in the a-arm). I'm not
saying this is a good design but there seems to be a reason for it.
Just my opinion... YMMV
'74 Midget undergoing Arkley conversion
'58 Morris Minor 1000
At 09:21 AM 2/27/00 -0800, you wrote:
>I do not understand why the fulcrum pin needs to be threaded at all? If
>grease impregnated bushings were pressed into the A-arms and king pin, why
>couldn't you use a hardened non-threaded pin, and allow free movement at all
>three points in the outer assembly. A circlip could be used to keep the pin
>from falling out, or fit a bolt to the narrow end.