breathers for CCKW/CHEVROLET 4X4 axle housings

RANGER · Post by **RANGER** » Mon Aug 21, 2006 10:18 pm

Be careful when purchasing new replacements, as most dealers do not realize they are selling incorrect vents. They all look the same but there is only one correct one. Installing the wrong ones can cause Oil Seal failure. Joel Gopan in Maine is the only person that has consistantly had the correct ones.

Guest · Post by **Guest** » Wed Aug 23, 2006 9:22 pm

And do the correct ones hold any pressure?

RANGER · Post by **RANGER** » Wed Aug 23, 2006 9:47 pm

Darned little, their purpose is to allow air to escape when internal pressures aer built up, and to keep water or dirt from entering, in the case of the WWII CCKW it barely keeps out splashed water. The manuals explain what to do after fording.

Capt Lee P · Post by **Capt Lee P** » Fri Aug 25, 2006 7:04 pm

Thanks for your thoughts on air pressure build up on CCKW's tandem axles. My truck constantly built up pressure (5-10lbs) and did blow thru the oil seal and wiped out the brake shoes with oil/grease. I installed two Ford Part # F6TZ-7034-A (vent, axle breather cap) which are remotely mounted above the inside of the frame rails. I connected this with 20" of vacuum line to each axle.

RANGER · Post by **RANGER** » Fri Aug 25, 2006 8:33 pm

What is unusal about axle venting is that on the later G-742/G-744 2 1/2 Ton/5 Ton trucks is that parts meed ESC(Equipment Serviceability Criteria) specs. The vent will be removed and a tire valve type fitting will be installed in its place, and a small amount of air pressure applied. The axle assemblry will have to retain that pressure for a minimum amount of time, if not it will be repaired so that it will. This is to ensure that the xale is basiccally waterproof and that the steering knuckle boots and wheel seals ire in proper condition. The vent is then replaced. It is much like testing a radiator wher they apply excess pressure for testing purposes.
Nothing looks better than bright shiny NOS GI issue differential vents though. They are approx $4.00 USD ea. They are standard to all Army wheeled 4X4/6X6 vehicles issued from WWII thru the 60s. The ORD part number did not change.

I believe I have seen the guests plight concerning GO leaking out onto his rear brake shoes mentioned elsewhere. I remember at the time he had installed the wrong inner wheel seals, they did not match the specs of the originals which are still plentiful.