Deere 4720 wheel seals/ wheel hub internals

[johnesc]

I have a JD 4720, noticed the left front wheel was leaking real bad. Found the hub was moving up and down, which destroyed the seal before any other damage could occur.
After pulling off the hubs I found Left side hardened washed in pieces sitting in the gear area, Right side hardened washer is all broken, but in location, shown in pics.
Any idea what could have caused this?
Any one have a video for installation?
I found lots of videos on the snap ring type, but none on the retention nut, hardened washer, shim style.
TIA

 

[johnesc]

I must be the only one to have this issue.

 

[TractorTech]

I had a customer with a 4720 that had blown out the bottom spindle plug, but when I replaced, there was no noticeable wear in the hub.
Not familiar with the washer you are showing or a different style of hub you are talking about.

 

[johnesc]

The washer, nut, gear is the final drive. It's just out board of the plug you replaced.

 

[TractorTech]

Yeah, got that. I haven't looked at or done one of these before and I don't see what the shim in that position does. Tapered bearings on the shaft, but the shim is on the outside. Parts book shows the same thing. Also, the book shows the shim and a flat washer under that nut. I don't see the washer on yours. My thought is it was not assembled correctly at the factory and is just now showing up.

 

[johnesc]

The washer was broken to pieces along with the factory 0.065" shim, allowed the bearings to have no preload, axle moved destroying the seal, oil leaked out.

 

[oldnslo]

was there a lot of loader work done with the tractor? Just wondering if that could put additional loading or thrust on that assembly especially if on side hill or turning a lot.

 

[5030]

Hope you don't run in FWA all the time... FWA should only be used when needed.

Your king pin through shaft busings are shot and that allows the entire assembly to wobble. The upper and lower busing are replaceable btw. Once it starts wobbling, the seals start leaking and everything goes south real fast. Lucky you didn't destroy the pinion and drive gear.

 

[johnesc]

attached my write up for rebuilding the final drives on a JD 4720

 

[johnesc]

Hope you don't run in FWA all the time... FWA should only be used when needed.

Your king pin through shaft busings are shot and that allows the entire assembly to wobble. The upper and lower busing are replaceable btw. Once it starts wobbling, the seals start leaking and everything goes south real fast. Lucky you didn't destroy the pinion and drive gear.

We only use MFWD when needed, the wobbling was due to no preload on the taper roller bearings.