Vented fill plug for rotary mowers

mf175s · Sep 26, 2022

I am in need of a vented fill plug aka breather fill plug for a rotary mower. Believe its either 13/16" or 3/4" threads. Has anyone found a place that sells those reasonably?

glennster · Sep 26, 2022

mcmaster carr has them
poke here

mf175s · Sep 27, 2022

(quoted from post at 18:33:56 09/26/22) mcmaster carr has them
poke here

Thanks!

Since mine sits on the side, I drilled a hole thru it and plan to put a pipe cleaner or something along those lines in it to keep dust out. That should alleviate the pressure enough to preserve the seals with cornhead grease in the gearbox.

caterpillar guy · Sep 27, 2022

Use a cotter pin through the hole. Pipe cleaner will wick water in from the fuzz on the cleaner.

DanielW · Sep 27, 2022

I'm almost certain what you have is 3/8 pipe thread (NPT), which has threads about 11/16 diameter (you
might have a 1/2 NPT, which is about 7/8 thread diameter, but both my Woods and Bush Hog mowers are 3/8
so I'm guessing that's it).

As mentioned, just grab a regular pipe plug from your hardware store and put a small hole and cotter pin
through it. Or, if you're really worried about a tiny amount of water getting into it, any Bush Hog or
Woods mower dealer likely has them. 3/8 NPT: Woods part #39325, Bush Hog Part # 81572.

Or just ask your nearest farm dealer if they have vented pipe plugs - lots of gearboxes on other equipment
have NPT vents and there's a good chance they have something sitting on the shelf.

504 · Sep 27, 2022

I put a 90deg in the side and changed it from 1/4 to 3/8 and used a breather
plug from a hyd cylinder. I use the plug on the other side for a check plug. I
fill in the 90.(gearbox leaks after a new seal, so I just fill it every usage)

Vented fill plug for rotary mowers

mf175s

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glennster

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mf175s

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caterpillar guy

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DanielW

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504

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