how to remove bearing on Modern AG 5ft shredder

Hello everyone,

I bought a Modern AG Competitor 5 ft shredder with a Kubota B7800HSD (my first real tractor!), and when I revved up the shredder the first time I noticed dark gear oil coming past the seal where the PTO shaft connects to the shredder gearbox. There is a good bit of play in the bearing (easily 1/32 of an inch) where the input shaft hooks up to the gearbox, so I thought I might as well replace the bearing and not just the seal.

I already know I need to find some flat snap ring pliers to remove the internal snap ring, but I wonder if the bearing is also pressed onto the shaft or into the housing around the bearing (or both). The bearing seems pretty stuck in its housing, but that may just be due to rust.

Does anyone know if I will need a bearing puller to get this bearing out? The nearest Kubota dealer can replace the bearing and seal for about $125 in labor (unless they decide to charge more), but I would love to do it myself. This is the the first time I have taken apart a gearbox like this, so I am not sure if Modern AG builds them differently than others.

I am hoping someone in this forum has taken one of these apart. I asked one of the mechanics at the dealer if the bearing is pressed in, and he didn't know. The bearing at the other end of that shaft came right out of the housing (at the back end of the gearbox), and it is pressed onto the shaft. This is a 48HP Max gearbox. I am attaching a couple of pics.

Thanks,
CuriousGeorge

Made some progress today and looks like I answered my question

I removed the internal snap ring with one of my smaller snap ring pliers and with a couple of gentle knocks the housing/flange around the problem bearing came right off. There is another smaller snap ring before the bearing (that does not have holes in it) which was a bit harder to remove, but I managed to remove it and now I can tell that the bearing is indeed pressed onto the shaft. Waiting for bearing puller kit to pull the bearing off.

The parts diagram on the manufacturer web site is a bit hard to read, so I am attaching a couple of more pictures for the next lost soul trying to figure out how this comes together.

Also, it's nice to see that if I only needed to replace the seal, it can be removed from the outside without disassembling anything.

Overall this gearbox seems to be well made - both bearings fit in their housings nice and snug.

Dave_eng said:

Before trying to remove the bearing, carefully polish the shaft above the bearing to smooth out any burrs or digs.

A tiny bit of metal being jammed between the inner bearing race and the shaft can make things get nasty.

You can also cut the bearing with an angle grinder and cutting disk to free it from the shaft.

Dave

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Thanks! I had to use a sledge hammer and a pipe to remove the sheer pin yoke because the sheer pin created a burr on the shaft. Already filed that burr down, but will polish the shaft before pulling the bearing. Great idea on cutting the bearing - I appreciate it! I will at least cut the outer race to make it easier to grab the inner race with the bearing puller.

Thanks again... the new bearing puller came in and it made quick work of removing the bearing. Other than initially installing the wrong seal on the cap and installing the cap upside down, it all went well. Knocked bearing in with a piece of PVC pipe that fit around the shaft perfectly. Will have to remove cap and install it with the notch downward (I bet that helps bathe the bearing in gear oil).

here are pics of the inside of the gearbox housing and the cap installed upside down. According to a couple of pics I have of the shredder before I messed with it (and a couple of pics of similar gearboxes online), that notch at the top should be at the bottom

a couple more pics on bearing with snap ring installed (which went on a lot easier than it came out), and the seal installation. The big internal snap ring installs into the cap.

The bearing puller and bearing/seal driver kit cost less than the dealer would have charged to install one bearing, so I'm glad to have those!

Dave_eng said:

From your photo, the snap ring securing the bearing to the shaft looks stretched.

It does not look like it is squeezing the shaft where the two open ends are.

Dave

Click to expand...

I'll pull it and check it again. It took a good push with the screw driver to get it in and it sounded like it snapped in. Nothing wrong with double checking though

GeoHorn said:

Congrats!

Where and How much did you find the pullers and presses?

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Amazon... Bearing puller set was about $59 with tax, and the bearing/seal press set was about $30. Already used the bearing and seal press a couple of times on my trailer after replacing bearings and a seal without it once. I thought "this has to be easier" - and it is (with the right tools)!