.... Dana 70 Axle vent thread pattern is 7/16 x 20 = Confirmed ! --- Thank You Subway
18-years is pretty good for me; and, after the fight I had today, I can see why I kept procrastinating.
Here is
Amazon's offering; Mopar; but I can confirm it fits a Ford just as well.
Amazon also has the Dorman and I am pretty sure I looked at the Dorman at RockAuto as well.
I opted for the Mopar as I didn't care for the barbs on the Dorman, plus I liked the stainless of the Mopar.
I did get stainless; some reviewers were complaining that they got brass instead; being hollow and quite thin-walled, I am sure stainless will break easy enough and I would imagine brass would be brittle as an eggshell.
Go to the link and then click on the reviewer photo that shows three variants side-by-side and read what he has to say.
Catch the part about both the new Mopar and the Dorman being of larger diameter than the originals.
I ran into that as well; although the thread size is 7/16-20, just like the original, from there on up the shaft is just enough larger that it will not pass through the original brake-block splitter thingie.
I laid under there and twisted a 7/16 drill bit through that hole using a pair of Vise Grips as I couldn't get any drill I had within a mile of there; once reamed with the 7/16 bit, the new fitting fell through with a hair to spare.
The one I got came with Blue Thread-Locker already applied; I don't know how much good it will do as I slathered the whole thing with that silver stuff.
On a Ford, with that second fuel tank about two inches away from the axle tube where this vent goes, it is one ordeal to drill the old out, re-thread, and get the new in.
I had to cut and custom make very short drill bits, cutting away material from both ends of the bits; this is where my Harbor Freight drill bit sharpener and Drill Doctor really shine and pay their keep; I use the Harbor Freight sharpener to grind the initial point on the cut-off bit and then use the Drill Doctor to make her razor sharp.
As the little Harbor Freight right-angle drill adapter is 3/8 capacity, I had to sacrifice my 3/8 reduced shank 25/64 bit to cut down for the tap hole.
I have several powered right-angle drills; but, that little Harbor Freight right-angle drill adapter gets in places those others only wish they could go; it has saved my skin on a number of occasions.
To add terrible insult and injury to the extreme close quarters work, the very first drill bit I poked in there was drilling away when, all of a sudden, the bit caught and yanked the drill; and, somehow, that stupid lock-the-motor-in button got engaged and the drill went wild and snapped the bit off deep in the hole.
I spent hours with the "Dremel" with that long "hose" thing with various Diamond cutters and finally ground away the last of the broken drill bit; I couldn't ever get the Dremel thingie straight in line with the hole and had to go at it at an angle.
After the nightmare fight I had today, if I ever have to do it again, I will move to easier accessed territory and drill an entirely new hole and leave that brake line splitter to it's own devices like it has been for probably thirty years anyway.
My vent had rusted away years ago and rusted over and had never leaked a single drop; I now wish I had left it be and just drilled a new hole somewhere else.
Now, before anyone panics, I pulled the axle and stuffed a rag with a rope past where I was drilling.
After all the drilling and threading was over, I pulled the rope and that pulled the rag out and hopefully all the shavings and grit along with it.
