m38a1 vacuum/pvc lines

1950 - 1968, M38, M38A1, M170, modifications, sugestions, and ideas, official MWO's and unofficial field mods.
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novafied
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m38a1 vacuum/pvc lines

Post by novafied » Fri Jan 04, 2019 9:06 pm

hi, i'm removing all of the vacuum lines as I have a replacement carb and fuel pump. what is the right way to reconnect the pvc/crankcase breather system? I wanted to install a 12 volt fuel pump but I want to use the vacuum wipers. the replacement fuel pump doesn't have any vacuum assist for the wipers. what is the best way to hook up the wipers? would i need to use the pump spacer with any of the replacement pumps? i'm still looking in the boxes of parts to try to find it. is the spacer easy to get? thanks for your help....bob

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Re: m38a1 vacuum/pvc lines

Post by Joe Gopan » Fri Jan 04, 2019 9:59 pm

The original M-38 and M-38A1 pumps require the 800361 Spacer, the CJ-3A/CJ-5 Vacuum Boosyer type pumps require the thinner spacer.The MB thru early 50's single action pumps w/o the vacuum booster do not use the spacer.
Buy some M-38A1 TM's and reinstall the original vacuum lines along with a new M-38A1 pump. You can just install breathers at the fuel pump section.
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HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
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novafied
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Re: m38a1 vacuum/pvc lines

Post by novafied » Sat Jan 05, 2019 10:37 am

thanks ben for the reply. I have most of the tm's for the jeep. I just don't want to all of the vent lines as i'm not doing a so called restoration. i'm keeping the military look on the outside. sort of like a trail ride off road jeep like they were meant to be. I don't have any 24 volt stuff under the hood as I converted all to 12 volt. I just want the basic to make sure the engine is properly vented. I am researching about the cj 3a fuel pump as it has the vacuum hookup for wipers. I hope it comes with proper spacer as no mention of it in ads. looking forward for more advice. thank you...bob

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Re: m38a1 vacuum/pvc lines

Post by Joe Gopan » Sat Jan 05, 2019 10:42 am

The SPACER for the Vacuum Booster Fuel Pump used on the 4 Cyl CJ is thinner and does not come with the pumps. The CJ Spacer is Willys Part No. 647669. Check with your favorite dealer.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

novafied
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Re: m38a1 vacuum/pvc lines

Post by novafied » Mon Jan 07, 2019 7:03 pm

hi ben, thanks again for your reply. I found most of the info I needed on the cj3b.info website. a lot of good info as it uses the same engine. but it's one ugly jeep imo. thanks again....bob


TonyRumore
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Re: m38a1 vacuum/pvc lines

Post by TonyRumore » Tue Jun 18, 2019 7:11 pm

I hope you guys don't mind me jumping in on this thread, but I've got the same issue trying to figure out how to hook up the vacuum wipers. Here's a pic of what I have going on.

There is a vacuum line running from the intake manifold directly below the carb, to the bottom of the fuel pump. The same hard line has a "T" in it and it also runs through what appears to be a check valve and into the side of the block, underneath the exhaust manifold. I don't see any spacer or anywhere to hook the wiper vacuum line. I'm guessing there is some sort of spacer with an attachment port that hooks to the wipers, but I don't know where that spacer is to be installed.

Image

swampy
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Re: m38a1 vacuum/pvc lines

Post by swampy » Thu Aug 08, 2019 4:41 am

the fuel pump is not the correct one

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