willysmjeeps.com

So, I got new, "correct for M series" vacuum wiper motors. On the old ones, the acorn nut on the extruding pole screws off, and you push the wiper blade arm on, then screw back on the acorn nut. These new wipers I though would be more or less the same, but the end cap doesn't look like it is removable. I don't see any threaded inserts, and I didn't want to apply too much pressure with a plier and brake it. Can anyone tell me how to attach the wiper blade arm to these things?
They also apparently have two vacuum ports in, no one like the old motors. Can anyone tell me why?

You got what appears to be wiper motors for M151 and others. You will have to modify them to work for the M38/A1 jeeps. I put a pair of M151 wiper motors on my M38 after some modification and they work great.
Kendall

What do I need to do to modify them? Does the M38 have only one vacuum line? If that's the case, what did you do with the extra one on the motor?

You can use the bracket that fits through the windshield from the old motor (or cut that longer bracket off of the new one) and then cut and thread the shaft to match the old one.
M38 wiper motors use two vacuum lines.
Also the spacers on the old motor are on wrong. They should be placed like the new one.
Kendall

Oh, I know the spacers are wrong, I just bolted them back on after I pulled it off so I didn't lose them. The double vacuum line, is it all from the single source, and I just need to find a splitter (maybe at Home Depot) to divide it into two lines?
As far at the bracket that protrudes through the windshield, are you saying I can use the old one? Pull it off the old motor and install it on the new one?

The motor on the left has the suck tube connection that goes to the vacuum "T" under the hood. The center rear side in the middle has a raised panel that is a hood over the vent or air in port.

The motor you have has both ports with tubes for 7/32" hose. One tube goes to the suck source (left side from engine) and the other is the vent in (to right side and air cleaner).

If you have your M38 configured to the early vent and fording systems then the vent port tubes are not connected to anything. If you have your M38 plumbed to the late configuration vent and fording system then the vent port on the wiper is connected to the air cleaner under the hood.

Your new motor is not a M151 motor. If it had been a 151 motor the manual arm would have been upside down.



Take a look at my M38 wiper album:
http://www.willysmjeeps.com/v2/modules. ... _album.php

This is the back of the current motor.

I have a 1952 M38A1. The original motors only have one vacuum port.

I think this is what the original M38A1 wiper motors should look like (half way down the page on the left side):

http://www.midwestmilitary.net/m38a1p12.html

Hard to tell from that tiny picture, but they do have two ports. There was a pair on Ebay a while back. Sadly, the M38A1 wipers won't fit my M38 (the manual handle would be upside down). Note that the manual handle on your replacement motors is correct for the M38, but the M38A1 should have the handle mounted "underneath". Maybe you can modify them?

One point about those replacement motors you got; the wiper arm pivot (the bit that the arm fastens to) is too long for the M38 and hits the bonnet. Not sure if you'd have the same issue with the M38A1.

The M38A1 after oct 53 came without any fording plumbing which meant no right side wiper plumbing to the air cleaner which meant the cheaper wiper was used from Oct 53 on and as new wipers were needed the Army only stocked the last production type towards the end of the vehicle's useful life which meant many older M38A1's ended up with the non-vent plumbing tubed wiper. Both my M38A1's came with the no vent tube on the right side and a vented tube model wiper on the left side. Both were 1952 models.

Your two new motors are really not original OEM Willys M38 motors. They are very late production generic M series motors that come two ways. Handle up and handle down.

Well, the thicker tip on the new motors doesn't fit through the hole in the windshield frame. The old motors had the acorn nut, which was removable. I couldn't unscrew these new ones, and I didn't want to break them with pliers. I haven't installed them either, I can't with that thicker tip, but I'm now thinking the manual wiper handle might sit too high for the canvas top.
Wes, do you have any idea what they are for if not the Mutt?

Clamp the knurled end in a vice and tap the shaft out of it with a punch. Then using your old motor measurements cut the outside tube to length. Do the same with the inside shaft. Then you tape back the correct distance using the tape as a guide, and file the shaft by hand smaller until you can use a 10-32 thread die and tap the shaft to recieve the brass nut that holds the wiper arm on. It works well. The die with it's progressive cut actually leaves the taper that the wiper arm locks against with the nut. Much cheaper than NOS wiper motors or 110.00 each for the rebuild plus shipping. The Jeep Police may not like this though John

The manual handle can be reversed by removing the front mount plate,
removing the retaining pin by use of a small punch move the handle
180 deg and replace the pin..

I solved the problem by just ordering the correct ones from John at Midwest Military. I figure I can sell the new ones, and sell my old motors (they work, just not very well), and almost break even.