[wslade2]

I recently just had this same item, and obtained from Oklahoma Aircraft Accessories. They sent out a rebuilt and I sent in the old. Don't know about getting just a screw. Looks like broke off due to corroded in place. Probably time for a rebuilt unit.
It started with leaking fuel pump...so I changed the old fuel lines, then this assembly, the spider and cleaned injectors. starts and runs like almost new. Also felt like cheap insurance getting these rebuilt parts in place. I got pump from Quality Aircraft Accessories.
It was a little rough when everything first put on, there's some pressure adjustment to be made for the pump. We stirred up some grit in the system that got in nozzles which was the "rough" part. Be sure to flush everything thoroughly with fuel on reassembly. Through the process, found out Oklahoma Aircraft Accessories can put your whole fuel system on the bench (pump, control, spider, nozzles) and adjust to your aircraft specs. Neat service (but did it ourselves in the end). They offered fast or slower/cheaper service-owners choice. Came right to the phone with answers to questions (I always called in the mornings).
Prior owner used Mike's Aircraft Fuel Metering Service on the other engine. I believe I read they can do bench testing too...