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Front Differential vent tube question

BRONCITIS74

Full Member
Joined
Oct 4, 2015
Messages
340
Got the front of my 74 all apart to get cleaned, painted and lifted. On top of the differential, where the brake lines connect, there is the vent tube coming out. The fitting was plugged and the hose torn off, only about 1/2" of it remaining. How long is this hose supposed to be and where does it go? Thanks for any help. Mike
 

Brent13

Sr. Member
Joined
Aug 1, 2015
Messages
673
Loc.
Colorado Springs
I ran mine up to the driver side engine bay, and secured to top of fender. Basically, needs to be higher than whatever water you plan on crossing. I do not plan on water crossings higher than top of fenders! I believe there is also a breather plug for the Ned of the hose, but I do not have one, just an open hose.
 

B RON CO

Contributor
Bronco Guru
Joined
Jun 29, 2016
Messages
2,428
Loc.
Statesville, NC
Hi, X2. I used a piece of fuel line to raise it into the engine compartment, away from splashing water. Good luck
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
35,133
Stock they are generally shoved into a hole in the frame rail. Most people believe in the overkill theory, that is high up in the engine compartment. I generally loop it over the master cylinder. Open end pointing down so stuff can't "fall" into it. If it is sunk over the master cylinder, it's time to change the fluids no matter what. The hyper-paranoid will put a filter on the end of the hose. Not needed. There is almost no flow through the hose. What little there is will flow so slow any particular matter will just stick to the inside of the hose. I've pulled factory vent hoses off junk that has been abused for decades in AZ dust and the hose is always clean inside by the differential, if it hasn't rotted off with old age. You get more breathing done on a vented gas cap but nobody worries about putting a filter on that.
 

sykanr0ng

Bronco Guru
Joined
Aug 11, 2014
Messages
5,363
Another option is a breather bladder, the bellows expands when the air gets hot and contracts when it cools, the system is closed so nothing can get in.
This allows a shorter hose to be used.
 

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JSBX

Contributor
Sr. Member
Joined
Mar 10, 2010
Messages
617
I ran the hose into the engine compartment. I had some hard brake line that fit in the hose and cut it about 4" long and flattened one end. Drilled several small holes in it and inserted open end into the hose. Zip tied it to the master cylinder. This will keep a dirt dobber from plugging it up or other large objects from getting in. Did the same thing for the rear just ran under the bed rail.
 

Broncobowsher

Total hack
Joined
Jun 4, 2002
Messages
35,133
Another option is a breather bladder, the bellows expands when the air gets hot and contracts when it cools, the system is closed so nothing can get in.
This allows a shorter hose to be used.

Those are for ATVs, with a tiny diff. They don't have nearly the air volume of a truck diff and (for a rear diff) don't warm up nearly as much.
 

sykanr0ng

Bronco Guru
Joined
Aug 11, 2014
Messages
5,363
Those are for ATVs, with a tiny diff. They don't have nearly the air volume of a truck diff and (for a rear diff) don't warm up nearly as much.

They sell them in larger sizes now, the ATV guys that moved up to J**ps and such wanted them, so someone started making them.
 

jckkys

Bronco Guru
Joined
Mar 15, 2012
Messages
5,205
If you like over kill you can do what they did in post WW II military vehicles with fording capabilities. They have vent tubes from all the gear boxes, differentials, distributor, etc. routed to the clean part of the air cleaner, like the breather on the valve cover does. Heated air and vapors can get out with no resistance and no dirt or water can get in.
 

68ford

Bronco Guru
Joined
Dec 26, 2004
Messages
2,710
I ran a 90 degree fitting in the diff then a 45 degree AN fitting on hose and ran it up the radius arm with the brake line so no one can see it. Attached it at the frame pointing down to the ground with a p clamp.
 
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