willysmjeeps.com

Can someone that has mounted the M151 motors to their M38 or A1 and had to cut off their shafts to fit please advise the part number of the motor?

Thanks!

These are what I modified and currently have on my M38-
Trico 7017830. Then there is a paper sticker on the back side that has the number SK 527-16.
Kendall

I'm trying to identify the wipers being modified
by our members by shortening the shafts.

They are all identified as M151 wiper motors.

Here is a post:

http://www.willysmjeeps.com/v2/modules. ... 151+wipers

According to several postsbtge M151 wiper shafts are too long
and will cause the wiper end to hit the windshield.

The specs shown for the M151 show the shaft shorter than the
M38/A1 shaft.

I guess I don't understand why the shafts are being cut off
if they are already shorter.

Brian,
What I would recommend is for you to buy one (or two) of the above mentioned wiper motors. Then instead of comparing spec sheets you have it in hand and can make the necessary modifications work. I don't know what it means that the shafts are too short. The MUTT shafts are too long and have to be cut shorter and then narrowed down and threaded to accept the acorn nut. That is what I have done and they work (except I don't drive this jeep in the rain so can't say for sure how well they do work. I know that the motors worked very well while I was testing them).
Kendall

Thanks Kendall.

The part numbers listed on the other post and yours
help a lot. Sometimes if you get lucky they show the
part numbers on listings.

All the M38 and M151 wiper motors are simply a joke. Even brand new ones. I think the vacuum case on them which is smaller than a CJ3A type trico is the reason. Not enough power. All the double acting fuel pumps I've tried, M38, civi CJ, and even Chevrolet are also a waste of money. They do not help. I was looking into a electric vacuum pump to try and boost the vacuum supply when it finally hit me, why do that? Just buy a electric wiper motor and be done. The best are the American Bosch series. Some have 2 speeds, some are 6 volt, some are 12 volt, switch on the motor, or separate dash switch. They are metal fabricated and very tough. They also are small enough to fit right in place of the vacuum units. They show up on ebay if you watch.

So, the only thing in my mind the vacuum units are good for is looks, correctness, and a good work out for your free hand! John

Yes, I am installing 151 wiper motors on my M38 now. The shafts are indeed longer, as stated, so I will cut them off, file the ends and thread them for the brass nut that holds the M38 wiper arms. I think they are 10-32.
The other difference is the inlet tubes are straight on the 151s and curved 180 degrees on the M38s. I don't care how vacuum wipers work as I don't drive my vehicles in the rain. And use rain ex. But most of them work well enough. Maybe your vacuum system has a leak.

I ran the stock Vacuum wipers on my M38A1 from 86 thru 90 in Rapid City SD no issues. Having started out in the early 60's with my first three cars having vacuum wipers I learned to properly maintain them and not expect more than they were capable of like trying to pass another vehicle going up hill while accelerating with a 4 or 6 cyl engine in a driving rain! I ran stock vacuum on my GPW 71-73 in Louisiana, on my 60 CJ3B 96 thru 2002 and my Dodge M37 from 2006 thru today all without any serious handicap. The GPW and M38A1 were both daily drivers. The M38A1 got me the 20 miles each way from Blackhawk SD to Ellsworth AFB SD and back in freezing rain, snow with no difficulties.

If I planned on driving my current M38 over 55 on highways everyday I obviously would not have a bone stock M38 and would use electric wipers so I wouldn't have to slow down so much.

I'm going to take the shortcut with a pair of M151 wiper motors and mount them behind a couple of spacers each so I don't have to disassemble and cut-weld the shafts. A little light filing to get a die on the shaft for an acorn nut is about my top speed.

Best compromise I can do right now. Sure as h*ll ain't paying $150 for a NOS M38 motor. That seems to be the asking rate now and there appears to be plenty of them popping up lately. What are they made of --- gold? Good grief.

I paid $60 for a pair of NOS M151 motors - delivered. That's more like it. Especially since the truck isn't likely to get wet anyway. And I've got goggles.

Thing is, particularly in Texas, if you want to get it inspected it has to have
on it and working what came from the factory. Turn signals? No. Wipers, yes.

All I care is when the hand at the inspection shop turns that little knob that they swing back and forth.

Without several hundred bucks in canvas I'm not driving in the rain anyway!

Just don't turn them on until you are going down hill.! Also turn on one at a time while shutting off the other, but on M38's the shutoff feeds both, so maybe a extra shutoff is in order.

oilleaker1 wrote:Just don't turn them on until you are going down hill.! Also turn on one at a time while shutting off the other, but on M38's the shutoff feeds both, so maybe a extra shutoff is in order.

An extra valve would be nice. In a pinch Ive had to pull off and kink the rubber line of the passenger side in order to get more out of the driver.

Haha! Bubba would be proud!

Keep in mind gents the vacuum side of the dual fuel/vacuum pump is a booster not a primary pump. The achieved vacuum at the wipers is the sum of the manifold vacuum and the boost. Either one less then spec will equal poor wiper performance. That is why the vacuum test gauge was a much more commonly used tool up thru the 60's.

Just pull the hose off and suck on it!