CJ2A axle tube hole ?

1945 - 196*, Willys CJ series, questions, discussions, regarding anything related to the post war jeep.®
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Wolfman
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CJ2A axle tube hole ?

Post by Wolfman » Thu May 26, 2016 12:06 pm

I have a CJ-2a in the shop.
Customer ask me about the small ( 1/8th inch) hole in the left rear axle tube.
On the rear of the axle tube. Just below center and just inside of the inner u bolt that holds the axle to the spring.
??????
Checked my CJ and one other on the lot and they both have one.
What is it for ???
Mike Wolford
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Re: CJ2A axle tube hole ?

Post by Joe Gopan » Thu May 26, 2016 2:14 pm

Relief holes for wheel rear bearing grease.
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Bob W
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Re: CJ2A axle tube hole ?

Post by Bob W » Thu May 26, 2016 6:18 pm

In addition to the grease relief holes at each rear wheel bearing, the hole inboard of the left side u-bolt is the axle vent.
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Re: CJ2A axle tube hole ?

Post by Joe Gopan » Thu May 26, 2016 8:34 pm

Was this axle vent hole on both the CJ Spicer 41 and the CJ Spicer 44?
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Re: CJ2A axle tube hole ?

Post by Bob W » Fri May 27, 2016 1:55 am

Yes, I'm not sure when they finally went away from the simple hole as a vent. Here is some Willys info on the topic.....

Image
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Re: CJ2A axle tube hole ?

Post by Wolfman » Fri May 27, 2016 3:47 am

It is a good day ! I learned something new !! :D
The CJ the hole was discovered on is a new rebuild. Nice & clean.
The other two took some scraping to find the hole.
Guess that is why I never noticed it before.
Thanks to all for the intel !!
Mike Wolford
CJ-2A
VEP GPW
Comm./Inst. SEL
AOPA ( 50 yrs)
EAA ( 49 yrs)
4th Inf. Div. - 5th Inf. Div. - 2nd Armor Div. - CIB

Fortyeight2A
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Re: CJ2A axle tube hole ?

Post by Fortyeight2A » Fri May 27, 2016 8:39 pm

I modified my axle vent hole. I drilled and tapped it for a 1/8" NPT/1/4" flare fitting and ran a vent line to the top of the diff housing and put an inline fuel filter on that so it vents through the filter up higher than originally. It's probably not necessary, but if I go wading, I feel better. :)
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Re: CJ2A axle tube hole ?

Post by Joe Gopan » Sat May 28, 2016 4:27 am

The Army installed spring loaded pressure vents on the Spicer 44's of the M-38/M-38A1
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Re: CJ2A axle tube hole ?

Post by Wolfman » Sat May 28, 2016 5:17 am

I wondered about the logic behind this if you and your jeep go swimming.
The CJ axle needs a snorkel !
Mike Wolford
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Comm./Inst. SEL
AOPA ( 50 yrs)
EAA ( 49 yrs)
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Re: CJ2A axle tube hole ?

Post by Joe Gopan » Sat May 28, 2016 5:45 am

If the Jeep gets regular service, that small open vent should suffice, but the rear wheel bearings on CJ's and M-Series Jeeps seem to get ignored. The Army installed those spring loaded vents in order to have a more positive seal against water. Good thinking on their behalf.
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Re: CJ2A axle tube hole ?

Post by Fortyeight2A » Sat May 28, 2016 6:41 pm

I thought those spring-loaded vents were so you don't have to take the vent fittings off when you grease the rear wheel bearings.
Is it true real Jeeps have flat fenders?
Alone cannot you it resist!

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Re: CJ2A axle tube hole ?

Post by Joe Gopan » Sat May 28, 2016 8:31 pm

The vents are not removed, they stay installed. The Army had an urgent bulletin to remove the grease fitting and install a pipe plug in stead of the grease fitting as some vehicle operators were getting too happy with the grease gun and over greasing this location causing greasy rear brake shoes.
The rear wheel bearings are to be greased only every 12,000 miles.

The CJ's have open holes in the rear axle tubes above the rear wheel bearings to vent the pressure from fresh grease during lubrication, the M-38/M-38A1 have a pressure relief valve with a little nail like spring loaded pin that is rated at around #4. The little pin opens to allow excess pressure while greasing to escape. This also prevents water entru at this point. The Army thought this out well due to the fording considerations of the Post war Army Jeeps.
When greasing the rear wheel bearing, pump the grease gun very sloe and stop when the cap on that little pin starts to rise.
The pressure relief valve is threaded into the M-38/M-38A1 axle tube and has a 7/16" Hex and a 1/8" pipe thread.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
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Re: CJ2A axle tube hole ?

Post by Rus Curtis » Sun May 29, 2016 5:17 am

Ben Dover wrote:The rear wheel bearings are to be greased only every 12,000 miles.
It is good to see input to show how the Army applied changes to best suit their needs and how they differed from civilian jeeps. However, I think it's important since this thread and this section is for CJ's that the CJ Service Manual (SM) be referenced to avoid confusion and ensure Army procedures are specifically labeled as such.

My early CJ SM indicates for all models (CJ-2A - CJ-5/6, DJ-3A) to grease the rear bearings,

"Sparingly each 1,000 miles." My late CJ SM (late CJ3B- CJ-5A/6A, DJ-5/6) indicates,

"With Lube Fittings: Sparingly each 2,000 miles. Without Lube Fittings: Disassemble to lubricate each 12,000 miles."

I think this is an important difference.

This post is not an attempt to discredit the Army's published procedure. It is only intended to emphasize the difference in procedure and highlight what's correct for the CJ's.
Rus Curtis
'54 CJ-3B
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Re: CJ2A axle tube hole ?

Post by Joe Gopan » Sun May 29, 2016 5:24 am

And a note:
The M-38/M-38A1 use the same part number Rear Axle Shafts, inner/Outer rear Wheel Seals and Rear Wheel Bearings as the 40's thru early 60's CJ-2A thru CJ-5 with the SPICER 41 and SPICER 44 Rear Axles.
The rear Wheel Bearings on old 40's-50's CJ (and M-Series) tend to be overlooked for some reason and suffer from lack of lube.

There are problems that can arise from the method used to grease the fittings on the rear of CJ-2A thru CJ-5 and M-38/M-38A1. The proper method is to use only a hand operated grease gun and to lubricate slowly and carefully or grease may blow past the outer seal. Many do not grease the rear Wheel bearings with the necessary caution.
Back in the 40's-50's when Jeeps were more common, the owners sought out the garages that had good Jeep lube specialists. I remember my community had the Jeep dealer and a gentleman at the local Texaco Station named Ray Seymore.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
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Re: CJ2A axle tube hole ?

Post by Joe Gopan » Fri Jan 20, 2017 2:03 pm

And remember, CJ's 40's-60's CJ's had Vent Holes on top the rear axle tube, M-38/M-38A1 had the Pressure vents with spring loaded pin that would rise when sufficient lube was carefully pumped in. And again the bearings and seals for the semi floating axles were same part number for military and civilian.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
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