Can someone let me know what size tubing I need to buy for my vent tubes on the axles? Thank you.

 

What happened to your old vent tubes? (If any remnants remain, their inside ID's could serve as a guide).

I had to replace my rear axle vent tube. The tubing failed (cracked apart or something like that) immediately past the barbed fitting.

The hose failure appeared to be degradation of rubber from exposure to petroleum distillates vapors, so I replaced the line with SAE R30 fuel hose. I wanted a thick wall hose that would last longer than the 20 or so years that the original hose lasted.

Here is a photo of the ID and OD of the new fuel rated hose that I retrofitted.



I have spare sections of fuel and vacuum line on hand, so I wasn't faced with having to order a size. I just matched up what I had on hand that friction fit the barbed fitting on the axle snugly. I'd say the ID of the line was about 1/4".

I'm thinking 1/4" is also what was imprinted in writing on the fuel line, but to be perfectly honest, I never checked the ID printed, only the hose type and rating, as I matched the physical ID with both the remnant of the old hose, as well as the diameter of the barbed fitting. Still, I used a small fuel injection hose clamp to secure the new vent hose, as seen in the photo below:

(The new axle vent line of interest is actually the BLURRY "Made In USA" hose, not the grooved brake line that the camera chose to switch focus on)



Speaking of using fuel parts, I also added a fuel filter to the axle vent as a way to catch and evaporate any splash entering the end of the vent line. There are one way check valves available for this, but I didn't have one on hand at the time that I discovered the broken vent line.

 

Awesome post my man.

For clarity hose is measured by ID, tubing is measured by OD.

 

A while back I found the axle vent tubes to be cracked, dry and not serviceable in my opinion. I used some fuel line I had left over from the H/H mod. The 30R9 reinforced hose was a tight fit over the breather fitting, but I was OK with that.

I cannot help with the internal size, but I will add that a screen of some sort should be used at the open end of the hose. This screen will let the axle vent as required, but more importantly it will keep insects and debris out.

I used aluminum screen from another project and secured it in place with zip ties. Years later the hose and screen are still working well.

 

I’d be thrilled if somebody made a 304 stainless vent barb instead of the mild steel that gets rusted out and allows the crud to build up and stick to the inside that much easier. As for the tubing some 100% silicone vacuum line would be ideal for longevity. I get under there and blow into the end of it every so often just as a preventative check to be sure it’s open. Nothing fancier than that is super necessary IMO but that area does get a lot cruddier than say, the breather on top of the transmission so it has to be kept an eye on.

 

Old thread....but look for exhaust mufflers, silencers, vents at Grainger or McMaster Carr