Kubota belly mower keeps popping out oil cap????

[lharrell799]

Hello all,

I bought a B2910 with a 60" belly mower, last year. I have been using the belly mower to shred a pasture. The pasture is mostly grasses/weeds, with a few small mesquites. The mesquites are only about 1/4" to 1/2". The mower does fine with all of this. However, about a month ago, I was mowing and noticed the front oil cap on the gear box had popped out, and the gear box was empty. I disconnected the mower, took it home, cleaned everything and placed the cap back in the gear box and filled it up with gear oil. The cap fit very tight. The next week, I mowed about 5 acres with it, and it was flawless.

2 weeks later, I mowed about 2 acres. I looked down, and noticed oil all over the deck. I shut the mower down and inspected. This time, the oil cap on top of the gear box had popped out, and all oil was lost. The gear box was hot to the touch. What is causing this? Am I working the mower too hard? Is it possible I'm overworking it, causing it to get hot, which pressurizes the gear box? Maybe the gear box is building up pressure and pushing the caps out?

Anybody ever had anything like this happen?

 

[stevewarner1957]

Are you overfilling the gearbox? Hot oil expands and could pop the cap. Is there a plugged vent? Most gearboxes are vented. Sometimes the fill plug has a small vent hole drilled in them

 

[Wolfy]

Yep check the vent, once you get that resolved I would fill the gear box with Lucas Hub Oil, its incredible.

 

[lharrell799]

Hmmmm, didn't know these decks had vents. I will have to check that out. I'm using Lucas 80W-90, and filling it just until it seeps out of the inspection plug hole.

 

[lharrell799]

Ok, just checked the parts manual and messicks. There is indeed a dedicated breather plug on top of the gearbox. I'll check it out tomorrow.

 

[diesel85]

Sounds like the breather plug is clogged.

I recommend, before you fill it (and whenever you service it), that you get compressed air and slightly pressurize the gearbox. This will clean it out, along with putting some air through the vent hole.

 

[lharrell799]

Well, I pulled the vent plug today, and it was dirty. I couldn't really tell if it was completely clogged or not. Cleaned it up with some brake cleaner and then blew through the bottom of the plug. It is definitely not clogged now. Put everything back together, filled it up with gear oil, and mowed for about an hour. Everything seems well again.

The other day when I blew the plug out, I remember hearing a strange noise. I mowing, and I thought I hit a glass bottle in the tall grass. It wasn't a shattering glass sound, it sounded as if I had hit a bottle, and the mower chucked it 20 feet. It was a loud, hollow, "dink". Looking back at that sound, I'm pretty sure that was the gear box blowing the oil cap out.

Thanks for all the help.