This diaghragm is to rebuld the AFPR below in the picture. If the threads are messed up you may just need a new AFPR. Hint start the return line into the AFPR first. Then bolt the AFPR to fuel rail. Lube the o-ring and check the fuel rail for rust. We suggest that you inspect the o-rings at this time for deteroration or cuts. We carry the GM return o-ring.
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