Rear diff breather mod fuel line/hose size
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JSparky
New member
I forget which size I used, but the flexibility and wall thickness of various manufacturer hoses can change slightly. If you're using the Toyota oem axle breather barb I'd just take the barb with you to the auto parts store to get the perfect size.. that's what I did and takes the question out of it. Use a hose clamp if desired.
wild_turkey
New member
5/16" if you're using the OEM barb. I started with 3/8", but it slipped on too easily.
I have the silver union here and 3/8" hose. They fit perfectly. Inserts easily, Takes a pretty good pull and twist to get apart. I've got it right here. This is Toyota OEM part. The shaft of the union measures 0.363". The barb is 0.400".
With a clamp added, no way it would separate.
3/8 = .375
5/16 = .313
If you already have the union, measure it. For mine the 3/8" is best fit. If yours is different then you might go 5/16" or something metric.
With a clamp added, no way it would separate.
3/8 = .375
5/16 = .313
If you already have the union, measure it. For mine the 3/8" is best fit. If yours is different then you might go 5/16" or something metric.
No, the barb fitting is made to work with the tubing. If you use too small a diameter, the barb will stretch and distort the hose so that after the barb there will actually be a gap. that means there is no hold there. So instead of 3/4" of hose gripping / sealing, you may have 3/8" gripping / sealing. When the hose is pulled it contracts and grips. So you are now holding with only 3/8" length of tubing surface.
The tubing is supposed to fit very closely to the barbed fitting. The barb then mildly distorts the tube and it naturally contracts on the gripping / sealing side. So smaller is not better. The closest size is better. There really will never be any pressure on this fitting so it can't get blown off. It will only be pulled off. So you want as much of that gripping surface as possible. That area from barb to nut faces. The more contact you make there, when the tube is pulled, the more grip it will have. If there is a concern for undue pulling then you place a clamp but never over tighten so as to distort the tubing and again reduce it's mating surface for gripping / sealing.
That's how hose barb fitting work. You don't shove them into the smallest hose you can make fit. that actually reduces their effectiveness.
That's why you either need to measure everything first or take the fitting to test fit in the hose. This is not a critical application but some are.
Saker
Senior Member
This is what I did and what I used....
http://www.toyota-4runner.org/1721720-post13.html
http://www.toyota-4runner.org/1721720-post13.html
A properly secured hose clamp will likely make all of them work...
Saker
Senior Member
Anything that is the same size as OEM or larger will work fine. I prefer larger than OEM.
Yes, I used clamps on all connections.
Remember to let the rear wheel droop as much as possible before anchoring the hose.... giving it room when flexing!
This will assure your hose will not disconnect.
