Quote:
Originally Posted by Sheepdip
I believe the third line was for an A/C truck and was a fuel pump by-pass return line to help prevent vapor lock.
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That's what I've heard, but I rebuilt this 71 a/c without it, because i'm 99% sure it didn't have a return. Hopefully it won't vapor lock,
Gross
I believe this truck didn't have a return line because of memory, and how I found the truck when I tore her down. It's a numbers match original 402 A/C. I've had it since 89, the original owner was an old man who primarily left the truck alone.
A return line for example requires different tube retainer clips. This truck has them for 2 & 3 tubes where a return needs them for 3 & 4 tubes.
Additionally, if you look at the parts book, and if we're to assume it's correct and representing, the 71 took the shorter fuel pump (no return) and the single line fuel sender too. Regardless of A/C, it's straight forward.
If memory serves me right, the part's book calls for a return line for turbo hydramatic transmissions. Couldn't tell you why. Beginning in 1972. 71 takes a different fuel cap than 72 as well. Seems the 70 is the same as a 71.