Rear axle vent fitting. Here's a real head scratcher !

[Noonan]

Just pulled the axle vent fitting off of the 1940 axle. 

 

What I've found in the vent fittting is a check ball and spring that allows the rear end to pull a vacuum against the spring and check ball but will not allow pressure to escape from the axle as the check ball is seated in the direction that would relieve pressure from the axle. 

 

Wtf ? 

 

This cant be the right fitting for the job..  

Edited Saturday at 01:10 AM by Noonan

[TodFitch]

That is a Zerk grease/oil fitting of the type used before 1934. At least before 1934 for US built Plymouths, maybe they kept that style later in other assembly plants. I've got one on each side of my rear axle to grease the wheel bearings.

 

The vent, at least on my car and I think pretty standard for a lot of later years, is a special bolt drilled with a vent hole that holds the brake Tee mounted on the top of the rear axle.

[Noonan]

Ok good ! I haven't lost my mind.. 

 

I am familiar with the grease fittings for the outer bearings, mine have been changed to a new style zerk.

 

I'm looking over the t fitting here and the bolt is just standard with no provision for a vent.  I can imagine things got misplaced and changed over the years.  

 

I'll try and find a standard vent plug with the small tin dust cap that I've seen on some trucks over the years. 

[desoto1939]

Check with andy Bernbaum for the axle vent tube.

 

Also if you are using the zerk fitting to grease the inner rear wheel bearings this can become an issue by over greasing the bearings.  According to my 1939 Desoto service manual it states that you should not use a zerk fitting because it will force to much grease into the bearing and then over grease the bearings and then force grease out the other end of the drive shaft and grease can then get onto the brake linings.

 

The proper way it to remove the small nut then put wheel bearing grease on you thumb and push that into the opening. You will have to do that process several times.

 

Refer to your service manual in the lubrication section for your car.

 

Rich Hartung

desoto1939@aol.com  

[andyd]

Todds reply re the special bolt that holds the brake line junction is correct, I think it was the same bolt used for a number of years.

[Noonan]

Thank you for the heads up Rich.  Ive recently installed new outer bearings, seals, rebuilt the braking system etc..  so i am aware of the possibility of over greasing the outer bearing.   I appreciate the warning. 

 

 I packed the bearing quite well with grease before install so I shouldn't have to re grease anytime soon !  In reality anytime the drums are pulled for brake work or adjustment the bearing could be pulled cleaned and greased. 

 

If I ever sell the car I will have to relay the information since I can imagine someone overloading that outer bearing cavity with grease. 

 

It was really that vintage grease fitting that was in place as a high point vent that was a bit odd eh 😆