Air Cleaner Servicing

[ODRotorHead]

I apologize for asking another newbie question. I've been searching for days and haven't found definitive answers to my how and what questions regarding servicing of the M151 air cleaner (unmodified). How - The steps to follow, and What - What solvents to use.

The -20 doesn't offer much detail:
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TM 9-2320-218-20-1-1
4-28. Air Cleaner Servicing and Replacement Instructions
b. CLEANING AND INSPECTION
5. Filter element (5)
a. Clean with drycleaning solvent and compressed air.
b. Inspect filter mesh for breaks and corrosion. Replace if broken or corroded.
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M151 Air Cleaner Assembly 002.jpg

M151 Filter Assembly 002A.jpg

#1.) "Air Cleaner" -
a. I haven't found any mention of it in the TM - is there a recommended procedure for cleaning the top filter?
b. Is there a solvent that can be used (other than drycleaning solvent) to clean (flush) the filter element that won't degrade the filter?
c. Should the top filter be "oiled" after cleaning?

M151 Filter Assembly 001.jpg

#5.) "Filter Assembly"-
a. With regard to the use of compressed air mentioned in the TM, is that just to blow the solvent out of the mesh, or is there some sort of solvent spray assembly used in the cleaning process?
b. Is it correct to assume that the metal mesh should be pre-oiled after cleaning. If yes, would it be acceptable to put the filter in a bucket and pour oil over the top, allowing it to drain through for a period of time to shed excess oil? A different recommended procedure?

Any information will be helpful.

I've read some of the pros and cons of the K&N filter conversion. Is there anything new on that topic. Recommended references?

Thanks for your time and assistance.

Mark

[rickf]

I checked the 82 manual, the 71 manual and even the very first manual from 1960 and none of them say anything about cleaning the top filter so I would leave it alone. Also, just follow the manual and lube order, you do not need to prelube the mesh. Fill the cup to the line with motor oil and reassemble and you are good to go.

[ODRotorHead]

Just found this in the Aug '71 issue (225) of PS:

Air Cleaner Maintenance PS Page 12 - Aug 71.jpg

Page 13 not include because the information was not applicable to the M151.

Air Cleaner Maintenance PS Page 14 - Aug 71.jpg

Air Cleaner Maintenance PS Page 15 - Aug 71.jpg

The article doesn't address the top filter, but it does provide some good information. I'll keep researching.

[m3a1]

My advice to you would be - Don't get too mired in the details. An oil bath air cleaner is a good and efficient design. You can clean it out any part of the oil bath air cleaner with just about any solvent you desire (or no solvent at all), just as long as it cuts through oil and releases any build up of particulates....but, I assure you, expediency in the field is the general goal and expediency is anything that can get that machine back into service.

I often read about guys wanting to use good, fresh motor oil in an oil bath oil filter. Stuff and nonsense! Do that and you are wasting perfectly good motor oil. Wanna know what they used in WWII for refilling an oil bath air filter? Waste oil. Used oil that, most likely, had been in the crank case only a few minutes earlier. It doesn't have to be able to lubricate anything. It just has to trap airborne particulates which waste oil does particularly well. (sorry, I couldn't resist)

The goal is to remove the old oil bath oil because it has particulates in it, which is simply dirt and dust churned up by the fella ahead of you. However, I am doubtful that any of us use our machines to the degree that the oil in the air cleaner would need to be replaced more than once a year...if that. What we should be looking for is water intrusion into our oil filters which will sit in the bottom of the reservoir and start rust.

Thus, simply pouring it out and wiping out the reservoir with an old rag is a very sensible way to go about it. Naptha (dry cleaning fluid) does well in getting the junk out of the screen but anything (and I mean ANYTHING) that gets the junk out of the screen will do. Naturally, using water based cleaners means you have to spend some time drying things out which does much to explain why using solvents that are quick to evaporate are much preferred.

Cheers,
TJ

"You gotta let that shirt go." - Buddha

[rickf]

And I see looking through here where I said not to oil the mesh but somewhere along the line I did see where you should put a light film of oil on the mesh. I had thought about that in the past and wondered why it was not mentioned in the manual since we did it with all the heavy equipment we ran with oil bath filters. (Yes, I AM that old). out on construction site we cleaned the filters with diesel fuel and shook them out really well to prevent a runaway on the old Detroits from sucking in fumes.

[ODRotorHead]

Thanks Rick. I have absolutely zero prior experience with oil bath air cleaners, so I was just glad to find a helpful reference. I posted it for all the newbies like myself who are still trying to figure out how things work.

As an M151 newbie, I find the old PS Series (The Preventive Maintenance Monthly) to be a big help. I encourage anyone who's not familiar with PS (anyone who hasn't served in the Army) to check out these M151 specific PS topics:

https://m151jeep.com/technical-tips#20b ... fc552353f1

(Don't tell my wife but, after more than fifty years, I'm still in love with Connie Rodd.)

If anyone wants to download digital copies of entire PS issues, I've found two excellent sources (there may be more):

Radio Nerds - PS Magazine Archives
http://psmag.radionerds.com/index.php/Main_Page
On the left, check the entries under the "Indexes" category.

VCU Libraries Digital Collections
https://digital.library.vcu.edu/islando ... C%3Apsp%22
VCU (Virginia Commonwealth University) has a smaller collection, but they tend to be larger file sizes.

With regard to air cleaner oil, . . . I have no position on used vs. fresh oil. If I were to speculate as to why the Army changed its policy in 1972, I'd say, (I'd guess), that someone may have pointed out the fact that used crank case oil is even more toxic than clean oil and the Army decided to eliminate that unnecessary exposure to young troops by specifying, "Fresh Oil Only."

Just a guess.

[FoxMike]

I’ve read a bunch of those PS documents on the m151 site. What a great resource. Thanks to everyone on these websites that keep them running for the new guys like me (us).

This oil bath cleaner discussion is kind of funny. I changed mine over to the paper filter this spring and don’t even remember the rationale of why i did so. Nothing permanent done, so I can always change it back. The paper filter was around $25, so not exactly cost effective.