Axle Vent

-
SpeedThrills

SpeedThrills

FABO Gold Member
FABO Gold Member
Joined
Jun 3, 2008
Messages
2,582
Reaction score
1,447
Location
Very South Jersey
Does anyone know of a vent bolt that will hold the brass vee and is 7/16-14 thread?

I have a 9" Ford in my Duster and there is a solid bolt holding the vee on. So, of course, the axle is not vented. I haven't driven it enough for it to leak, but I want to "stay ahead of the curve".

Searching, I've found Ford (Dorman 924-263, has a fitting for a rubber hose) and Mopar (Inline Tube and Dr. Diff) vent bolts, but they're 7/16-20.
Mine is 14 threads. I can only guess someone changed the thread when they put the solid bolt in.

I really don't want to pull the axle out to weld, redrill and tap the hole.

I'm wondering, maybe I could drill a small hole in the bolt I have, weld a nipple to it and pit a rubber hose on it.

Hmmmm, maybe I could weld up the 20 thread vent bolt and retap that to 14? Nah, I doubt it.

Thinking out loud... and hoping there's a 7/16-14 available. :rolleyes:
 
Take about a 1-1/2” long 7/16-14 bolt, cut the head off, drill a hole, use some blue lock tight or thread sealant, thread it in and clamp the hose to it, run a hose up and to the back along the frame rail what have you. E-z-p-z
 
The Chrysler ones have a valve in them, and terminate right on the axel.

IIRC the Ford's were just a barb fitting and the hose ran up into the frame rail, there might have been a valved fitting on it up in there ( it's been a long time)

Drill the bolt, tap it for a fitting, put on a barbed nipple, run the hose up to the frame rail, probably best to go to the passanger side drivers side might have the gas tank vent depending on year.
 
There has GOT to be a bunch of vehicles used those. I'd take your bolt (or a sample bolt) and head for a junk yard
 
I'm probably going to make something, as 12many and Dana67Dart suggest.
The problem is, at least from my research, is that all the bolts available, that were used in production are 20 tpi, and I need 14.

I'm gonna look more. I can't understand why someone would change the thread in the housing, just so they could put in a bolt that defeats the vent.
:realcrazy:
 
Not sure what the”v” you mention actually looks like but if it’s what I’m envisioning and way it’s mounted you could drill the bolt you have from the threaded end just up to the underside of the hex head, then cross drill it far enough below the underside of the head so it is covered by the “v”
File flats on the sides of the cross drilling 180° from each other or the full circumference. Akin to a custom made banjo bolt like used in brake lines on a caliper.
 
So either retap the hole to 7/16 x 20 or the Dorman vent tube to 7/16 x 14. That's not a mountain, it's a speed bump.
 
SpeedThrills said:
I can't understand why someone would change the thread in the housing, just so they could put in a bolt that defeats the vent.
:realcrazy:
Click to expand...

A person that would replace a vent with a solid bolt is the same type of person that would just cross thread the 14 TPI bolt into the housing because that’s what they had laying on the floor.
 
do this leave the bolt holding the brass brake fitting in place -- move over a couple inches and drill and tap a hole for the 7/16 -20 thread -- go to the junk yard and take a wobble cap vent off any 8.8 in the yard ( 9/16 wrench needed to remove vent from housing ) -- when you drill the hole and tap it , place grease on the flutes of the drill and tap it will hold the metal shavings from falling into the housing
 
I wouldn't drive it with no venting. I had the vent clog in my 71 Jeep, and on a longer trip the gear oil would push past the axle seals.
 
Mine blew the D/S seal with a clogged vent on my 1500. Luckily I caught it when putting on my snows. Vent cleaning is now part of my regular maintenance.
 
I appreciate all of the ideas. Seems there are lots of ways to go.

I just ordered this: Mopar Rearend Vent Bolt

I'll carefully add some weld to it, get it turned to size on a lathe, and then run a die on it to 14 t.p.i.

:thankyou:

Edit: Thinking further, maybe it can't be chucked in a lathe because of the cap. I'll see what the machinist says.
 
Last edited:
RustyRatRod said:
So either retap the hole to 7/16 x 20 or the Dorman vent tube to 7/16 x 14. That's not a mountain, it's a speed bump.
Click to expand...
This got me thinking. Somewhere in the past, I remember something about root diameters being different for fine threads and coarse.

So I ran a die down the Dr. Diff bolt (linked to in post #13), which was 7/16-20 as received. I figured the worst that could happen is that the threads would be ruined, and I would proceed with my weld-and-turn plan.

The first picture shows after I ran the die. It worked! Second shows the installed bolt.

I know myself well enough to know that I can, on occasion, overthink sumpthin. So, I un-thinked this one! (Insert back-up beeper sound.)

Thanks for the ideas, they're what got me there! Plus, if someone searches this with the same issue, here it is.
1668368430953.png


1668368456367.png
 
SpeedThrills said:
This got me thinking. Somewhere in the past, I remember something about root diameters being different for fine threads and coarse.

So I ran a die down the Dr. Diff bolt (linked to in post #13), which was 7/16-20 as received. I figured the worst that could happen is that the threads would be ruined, and I would proceed with my weld-and-turn plan.

The first picture shows after I ran the die. It worked! Second shows the installed bolt.

I know myself well enough to know that I can, on occasion, overthink sumpthin. So, I un-thinked this one! (Insert back-up beeper sound.)

Thanks for the ideas, they're what got me there! Plus, if someone searches this with the same issue, here it is.
View attachment 1716010146

View attachment 1716010147
Click to expand...
And there you have it! Glad it worked out.
 
You must log in or register to reply here.
-

Back
Top