Joined: Dec 01, 2008 Posts: 64 Location: Lexington, KY USA
Posted: Tue Aug 11, 2009 6:15 pm Post subject: M38A1 Wiper Vacuum Line Routing
After having a blast at the MVPA convention in Evansville, it seems I forgot to take note (and pictures) of the wiper system on the M38A1 . What I need is either a good diagram or photo of how the vacuum tubing routes to the wiper motors. My M38A1's lines are all screwed up. I just know enough and have seen just enough in blury/pixelated images to know mine aren't routed correctly. Looks like I've got too much hose. So if anyone can post either a diagram or good, representative photo, I'd much appreciate it.
just rebuild my fuel pump fuel and vacuum.I have installed all the hoses,valves etc from one side of the vacuum that goes to the vavle cover and manifold.From the other side i just connected a hose and run it to the on-off valve and to the wipers.will this harm the vacuum side of the pump?because there is no air flow when the wiper valve is closed.
Probably not but if you are running the stock 24V military distributor and coil you really need to install the wiper "T" fitting and route the vent line from it to the distributor port and from the distributor's other posrt to the intake crossover. This serves two purposes. It uses vacuum to suck explosive ionized gasses from the distributor and two coils coil which increases coil life. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Posted: Tue Jun 13, 2017 7:22 am Post subject: hose length
Wes, or anyone, could you provide a measurement of the hose from the " t" fitting to the wiper valve? Is there a regulator located at the " t" fitting?
Sorry to ask this but I'm working on the windshield/ wipers here at home and the A1 is 5 hours away. I would like to make the windshield ready to install once complete.
Thx Jim _________________ James, 1952 M38A1
The IPL calls out 55" of 7/32" ID wiper hose from under the hood to the valve on the windshield. I put the length around 42" (running direct from "T" to valve) - 50" (using a clamp high on the firewall). Hard measurements of the various lengths found on everyone's jeep should give you a dozen or so different lengths to figure from.
The wiper "T" under the hood divides manifold vacuum between the wipers to the left and the distributor vent line to the right. The right side of the "T" has an 0.040 orifice in it to reduce suction to the distributor. The wiper side has no restriction or any other kind of regulator. just the 55" hose to the valve on the windshield which is the wiper air regulating valve.
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