VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Rear axle vent

I plan to replace both the inner and outer rear axle shaft seals with the newer style seals. Will I have to install a pressure relief port
in the axle housing? It would seem some type of pressure relief will be needed. Thank you 55637

With modern seals it is probably to have pressure buildup in the axle housing. That pressure can get high enough to force lubricant past the seals. Same situation if you use sealed bearings. So it is recommended to provide a vent.

I did what somebody here suggested and took out the top bolt of the differential cover and drilled a hole thru it the long way I think it was 7/64" diameter and then put a cotter pin thru the bolt.

My thoughts also on the pressure buildup. I had thought to drill and tap a hole in the top of the left hand axle tube then install a standard vent fixture. I do
like the differential cover bolt hole better though. Good idea. Thank you both!

Barefeet, is the cotter pin just run the length of the bolt and then left a bit loose? Having trouble visualizing...

I just measured mine, the hole is 1/8" and the cotter pin is 1/8", but it does seem a little loose and I believe it will allow air to pass. Spread the legs just enough to keep it from falling out. I am still in the process of restoring the car so have not road tested it. I don't know if others remove the cotter pin when driving.

Here's a pic of mine. It's been in the top rt. bolt hole position for approx 200 hundred miles. No significant leakage, just a slight weeping of fluid.

I did the cotter key through the bolt suggestion. Easy enough to do and makes sense. As a bit of trivia, many moons ago when I went through aircraft mechanic
school for Uncle Sam, we learned this method was used to relieve pressure buildup in aircraft engine magneto cases.