the vaccum wiper gets its power from a hose that is attached to the manifold.
jeep originaly came with a combination fuel/vacuum pump which powered the wiper. I have seen both single and dual wiper setups on these Jeeps. I'm not sure if the dual setup is an original option or not. My 51 has a wiper moter on drivers side and a hand powered wiper on the passenger side. Gave the passenger something to do on rainy days.
The CJ3A should have, as mentioned, a dual action, fuel/vacuum, pump. Keep in mind that if you install a dual action pump on your 3A, you will also need to install a spacer between the pump and block.
Read as follows:---
I have two vacuum wiper motor used in CJ3A, which completely disarmed to make them work even fabricated a new rubber seal on the piston, with a good result.
Later I bought the wiper arms of M38, which have a ribbed cone and I encountered the following problem:
The ends of the shafts of the motors are in poor condition,
therefore the striated cone does not fit well in the tapered shaft. Obviously missing the nut that secures it, but if I did, I note that the clamping area would be insufficient to transmit the torque and could loosen the arm and rotate the axle.
I say this because the small grooves that has internal cone, fail to connect to the shaft itself
I decided to buy two new engines for M151 on ebay, and except for some minor adjustment to fix the windshield was satisfied with his performance.
After finding out and seeing the figure of a vacuum motor M151 manual, I realized that at the end of the shaft is a ribbed cone which fits the arm, similar to the arms that I have.
But my surprise was that the engines are not aware striatum bought, but is a cylinder, and also the passage of the grooves is less than the cone that brings the arm.
How is the procedure to release the fluted cylinder, and replace the knurled cone brought the arm? Is this possible?
Apparently it is put under pressure, as the looming cap is smooth, and could not be with a screw.
Later I bought the wiper arms of M38, which have a ribbed cone and I encountered the following problem:
The ends of the shafts of the motors are in poor condition,
therefore the striated cone does not fit well in the tapered shaft. Obviously missing the nut that secures it, but if I did, I note that the clamping area would be insufficient to transmit the torque and could loosen the arm and rotate the axle.
I say this because the small grooves that has internal cone, fail to connect to the shaft itself
I decided to buy two new engines for M151 on ebay, and except for some minor adjustment to fix the windshield was satisfied with his performance.
After finding out and seeing the figure of a vacuum motor M151 manual, I realized that at the end of the shaft is a ribbed cone which fits the arm, similar to the arms that I have.
But my surprise was that the engines are not aware striatum bought, but is a cylinder, and also the passage of the grooves is less than the cone that brings the arm.
How is the procedure to release the fluted cylinder, and replace the knurled cone brought the arm? Is this possible?
Apparently it is put under pressure, as the looming cap is smooth, and could not be with a screw.
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take your wiper motor over to your bench vise and slip the shaft between the jaws, with the knob resting on top of jaws. Take a punch and hammer and lightly strike the center of the shaft. the knurled knob will come right off. I use M38a1 wiper arms on my M151 wiper motors (the jeep is a M38). If you are installing the motors on a M38 you will need a 3/4 inch stand-off between the wiper mount and the windshield frame. I don't know about adjusting for a M38A1 windshield. Be careful and don't let the motor fall on the floor when the knob releases from the shaft.
After you have the knob pressed off, you will see that the shaft of the arm is ribbed just like the outside of the knob. The mounting hole in the M38A1 wiper arm is ribbed to accept a ribbed shaft. A M38A1 wiper arm will press right onto the shaft with just a light tap from a hammer. Your Cj3A windshield frame is basically the same as the M38. use a 3/4 spacer betweem the windshield and motor mount.
I pulled the cylinder and pressure was actually on the end of the shaft, also striated. (Not very mild considering the diameter)
Now I upgraded to a 5.8 mm diameter of the hollow cone that I'm putting striatum, since he has, is smaller than needed.
Thinking about the procedure to put it is hitting, or in press, I am concerned that by supporting the engine vacuum could damage the rear which backs it, or the plunger is integral with the shaft.
I dropped the small back cover to see if I could directly support the opposite end of the shaft on something solid, and I see no risk of damaging the mechanism of oscillation.
I think I'll take the decision to place hot
But what surprised me is that by simply loosening two screws around the small cap, rubber stamp size has increased significantly, exceeding the cap, and has come all the way around
... it's inexplicable. 
It may be that the rubber is degraded by the type of lubricant used in the process?
Now I upgraded to a 5.8 mm diameter of the hollow cone that I'm putting striatum, since he has, is smaller than needed.
Thinking about the procedure to put it is hitting, or in press, I am concerned that by supporting the engine vacuum could damage the rear which backs it, or the plunger is integral with the shaft.
I dropped the small back cover to see if I could directly support the opposite end of the shaft on something solid, and I see no risk of damaging the mechanism of oscillation.
I think I'll take the decision to place hot
But what surprised me is that by simply loosening two screws around the small cap, rubber stamp size has increased significantly, exceeding the cap, and has come all the way around
... it's inexplicable. It may be that the rubber is degraded by the type of lubricant used in the process?
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The fuel pump is only a vacuum booster. The wipers normally run on manifold vacuum. The manifold fitting is connected to the fuel pump vacuum booster and the booster is connected to the wiper motor.
I have purchased a couple CJ-3A fuel/vacuum pumps from Walcks and they work good. They also have the necessary spacer too.
I got a good look at the fuel pump mounting position. The front motor plate where the motor mounts are attached, bends BACK toward the fuel pump location. I don't think a Vacuum/fuel pump will fit.
I have read that the frame brackets were not offset in earlier jeeps. Mine is a 3A frame with offset mounts and this was done to accomodate a Vacuum/fuel pump.
Was the frame in WWII Willys jeeps more narrow than the 3A?
There is a hexigon shaped brass or bronse spacer/mounting block attached to the motor mount which is attached to the frame. (Driver side only) This spacer looks like a real manufactured part. It looks cast. Not some fabrication job.
With the motor front plate bending back, am I going to have to use a smaller NON vacuum mechanical fuel pump?
I have read that the frame brackets were not offset in earlier jeeps. Mine is a 3A frame with offset mounts and this was done to accomodate a Vacuum/fuel pump.
Was the frame in WWII Willys jeeps more narrow than the 3A?
There is a hexigon shaped brass or bronse spacer/mounting block attached to the motor mount which is attached to the frame. (Driver side only) This spacer looks like a real manufactured part. It looks cast. Not some fabrication job.
With the motor front plate bending back, am I going to have to use a smaller NON vacuum mechanical fuel pump?
There was an adaptor made to allow a 3A front engine plate to be used on a 2A frame to allow the room needed for the combo fuel pump. It sounds like someone used that adaptor to do just the opposite and adapt an early plate to fit a 3A frame. The easy way to fix that is to get a 3A front engine plate and do away with the adaptor thereby allowing room for the combo pump.
Here are some front plate photos from The CJ3A Page showing CJ-2A and CJ-3A plates...
![[image]](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_t1VQGl8d3MUQT_nL0I306q5BITjT7bwYlM1KtJwi5AidS8NGfAUFGx5f7UVNjedjDgft3k7inRzLdioGSgwiCuRCOPiw=s0-d "[image]")
![[image]](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_uMcvZO9mfYzU-7PHQuzh1QRSqewDIDrEKm3o6AYr66TkWvyp4pVy7UIZecgAmbcFbKDGZp21KSwKxlrjsx0w6gJsqe=s0-d "[image]")
put the cj3a frontplate, flyhwheel on the engine and everything will fit.
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The wiper motor behind the steering is seen and the hose under the motor going to hood.
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some vacuum motors were mounted with the curved part up and some were mounted with it down from the factory?
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This is for bit different version but just for example:---dual wiper motors and with handles on both. bent tube is for drivers side and straight tube is passenger side.
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this is where the hose goes:---
On some models vacuum nipple in the head, directly below the carburetor on the passenger side.
you can operate your wiper motor from the intake manifold vacuum. However the vacuum in the intake manifold varies so much that windhield wiper action will be sporadic.
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For more help regarding fuel pump mounting issues on CJ jeep.Please click the link below and go through:---
