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m38 fuel/vac pump
Posted: Sat Dec 17, 2011 3:43 pm
by jerry72
Sent my pump to be rebuilt by then & now and they have reversed the suction and output line. Suction line from tank is now on the right (closeset to carb). Should I be worried and send it back or is it ok to use like this? Its the exact same pump, not a trade in and is period correct for the vehicle.
Jerry
Posted: Sat Dec 17, 2011 11:08 pm
by wesk
I would call them and advise them you are sending it back with an illustration of the correct stock configuration.
Use the photo that applies to your jeep below.

M38

M38A1/M170
It would seem they simply installed the upper pump housing 180 degrees off. ;
REVERSING THE HEAD ON AC FUEL/VAC PUMP
Posted: Sun Dec 18, 2011 2:38 am
by bluewatersailor
I had the same experience last month with a generically rebuilt pump. Contrary to what is advised in Para. 131, b (1) of TN9-8012, I could not find any line filed or scribed by the rebuilder to aid in reassembly. As delivered, it was sucking from the side that should go to the carb and puffing on the side that should go to the fuel tank. We encountered no problems in removing the head. rotating it 180° and reinstalling it while maintaining pressure on the rocker arm per Para 131, b, (8). N.B. - Although I have often read that these units cannot be bench tested, you can (and, now I believe, should) gently activate the rocker arm to at least determine if the head is on correctly. Good Luck.
Posted: Thu Dec 22, 2011 2:48 pm
by jerry72
Well I decided to remove the head and using the Para 131, b,8 instructions. after assembly I tested the arm and it worked fine. After installation it worked as it should. Problem resolved. On to the next issue
