Mk 2 Ruby fuel pump

[Joe eck]

Without taking a pump apart I cannot recall the screw mentioned. However A common topic on the old site was the variety of incorrect arms found on T type pumps which are common to many cars. I recall the arm numbers were quoted. 
Any wear on the arm insignificant cf gasket variations etc. If contact at the very tip, wrong arm.
(And the old advice. Care necessary not to assemble arm on wrong side of camshaft. This forces the arm heavily down and can lead to various damage)

Thanks Bob , from what you say , I think I may have a pump with a wrong arm as the contact area seems to be very low on the camshaft and easily slips under the cam when fitting if the operating arm is allowed forward too much.
Hopefully someone may have the correct part number or perhaps a second hand correct arm that I may be able to purchase ??
Thanks again for the valuable info.
Joe.