John Deere 4120 front axle seal replacement

Tundradog · Mar 22, 2015

I had a left front tire bead bust and the wire got wound around the outer hub. Leaking oil badly from outer seal now... I have a blow up pic sent from parts dealer shows the outer shaft, seal, bearing set, housing, inner bearing set, gear, shim, washer, and lock nut.
The question is. Can I pull wheel, unbolt the 8 housing bolts and simply pull out the hub assembly to replace the seal. Looks like the lock nut holds everything together. Contacted two JD dealer service shops and these guys aren't very forthcoming on DIY repairs. Told me I needed special tools etc. I have extensive mechanical tools including torque wrench.LOL.... I am guessing the lock nut is torqued to preload bearings but need torque specs. Local NAPA will press off the shaft and press in new seal for about $20.
Dealer quoted 70/hr labor plus parts... minimum 4 hours. Looks more like a 1-2 hour job. Being spring, they are all booked up through April... With spring sprouting need to get this fixed this week. ,

Tundradog · Mar 22, 2015

So, I just found link on line for diagram... need seal item 35, part number LVA14181. Looks like only need to remove wheel, unbold eight housing bolts and the shaft, gear housing come right off.No need to pull apart the rest of the drive knuckle.

Tundradog · Mar 22, 2015

John Deere - Parts Catalog

Forgot link to diagram..

Blueforester · May 9, 2015

Tundradog said:
I had a left front tire bead bust and the wire got wound around the outer hub. Leaking oil badly from outer seal now... I have a blow up pic sent from parts dealer shows the outer shaft, seal, bearing set, housing, inner bearing set, gear, shim, washer, and lock nut.
The question is. Can I pull wheel, unbolt the 8 housing bolts and simply pull out the hub assembly to replace the seal. Looks like the lock nut holds everything together. Contacted two JD dealer service shops and these guys aren't very forthcoming on DIY repairs. Told me I needed special tools etc. I have extensive mechanical tools including torque wrench.LOL.... I am guessing the lock nut is torqued to preload bearings but need torque specs. Local NAPA will press off the shaft and press in new seal for about $20.
Dealer quoted 70/hr labor plus parts... minimum 4 hours. Looks more like a 1-2 hour job. Being spring, they are all booked up through April... With spring sprouting need to get this fixed this week. ,

So how did your repair go? I just replaced front axle fluid a couple weeks ago and noticed this week that the front right wheel hub seal is leaking. Imagine that. I thought I was doing good preventive maintenance. I do all my maintenance myself. Just started researching how to replace this seal.

Blue

Tundradog · May 9, 2015

Sad to say... not looking good for my 4120.... JD was not helping to share repair specs. It is a two to four week wait to buy the service manual @$295.00... So I got the 4120 into the dealer. The seal was $44.00 and nut was $4.00 All total $389. Got the tractor home and put about 4 hours on her and daggon it the seall is already leaking again. So I call the dealer on Friday last week and they are so sorry... and tell me to bring it in right away and they will redo the seal. So I wait about 3.5 hrs and it all done. The guy takes the tractor for a spin around the lot 3-4 times, checks for leaks and we load er up and take it home. I bush hogged about 8 acres in two hours. Park it and bamm... it's leaking again.
Of course dealer is closed till monday. I will tell you, I saw another 4120 disassembled on Friday and the same service guy tells me JD stopped making the knuckle and its about $4K for a new one. As I am chatting with the guy he happens to tell me he saw a burr on my shaft and filed it down. Good grief... R you kidding me? I am betting the guy botched the job and knows it. I checked on line and a new shaft is over $500 but guess what .... not in stock. Apparently,these things are known for leaking seals and they do lots of them. BTW the second repair was no charge. Wish I had taken it to the dealer where I bought it... They warned me... If they can't resolve, I will do the work myself next time. It's just a seal for heavens sake. I will be calling JD corporate on Monday as well. Just ain't right that they won't keep shop manuals available and won't share torque specs over the phone...

whis · May 9, 2015

if he didn't file the burr it would cut the seal

Tundradog · May 9, 2015

Of course I will never know the extent of the damage if any that was caused by the steel tire bead material that got wrapped around the axle to begin with. I am always cautious when a mechanic goes after a scratch or burr on a machined shaft that is supposed to be perfectly round with out flat spots. If you remove to much material you may never get a seal to hold oil. Been there done that in my younger years. Often times I've taken a shaft and milled it a couple thousands and was able to use the OEM seal. Other times, you go out of tolerance and have to resize the seal or buy a new shaft.

Suffice to say, I don't have a ton of confidence in the local dealer at this point. Ordered the CD tech manual for my tractor....found it for $92 but have to wait 2-4 weeks. One must be very careful to not run these front axle knuckles dry. New whole knuckle assembly is $4774...

joecdeere · May 10, 2015

Couple of things here guys-

first off, shoot me your email, I have a PDF of the Tech manual you are welcome to for free

second, Deere just loves to put thin as water hydraulic oil in these front ends. They are nothing but big gear boxes, I worked in a dealer in the 90's and 2000's and when we had one like this we would, (with owners permission) put 145 wt gear oil in the front end. It is much thicker and would be a lot less prone to just pouring out like the water they use. You might still have a wet joint, but it just mighr be something you can live with for a lot less money. Just something to think about-
Good Luck

Joe

Tundradog · May 10, 2015

joecdeere said:
Couple of things here guys-

first off, shoot me your email, I have a PDF of the Tech manual you are welcome to for free

second, Deere just loves to put thin as water hydraulic oil in these front ends. They are nothing but big gear boxes, I worked in a dealer in the 90's and 2000's and when we had one like this we would, (with owners permission) put 145 wt gear oil in the front end. It is much thicker and would be a lot less prone to just pouring out like the water they use. You might still have a wet joint, but it just mighr be something you can live with for a lot less money. Just something to think about-
Good Luck

Joe

Joe ... email is reidnkim@hotmail.com Mine is serial number LV4120HCBH810311. 2011 model. I understand the Manual numbers changed post serial number 610001. TM105019CD is the tech manual they call for mine. I would really appreciate it. I have a assembled a part list for replacement of the shaft, bearings, bearing cups , seal and locknut. I like the idea of temp fix with heavy weight oil. Tractor is out of warranty so I am on my own. Service tech indicated there is some kind of bearing preload required that means a torsion setting. I am getting the idea they simply don't have the correct torques settings. I am thinking I can do the repair, mic the shaft for roundness and properly torque the shaft. Otherwise, I am off to the selling dealer to drop another $380 for seal replacement with no gaurantees. Really should not have to worry about a leak on the frond MWFWD. Thanks very much for helping with the pdf.

Tundradog · May 11, 2015

Tundradog said:
Joe ... email is reidnkim@hotmail.com Mine is serial number LV4120HCBH810311. 2011 model. I understand the Manual numbers changed post serial number 610001. TM105019CD is the tech manual they call for mine. I would really appreciate it. I have a assembled a part list for replacement of the shaft, bearings, bearing cups , seal and locknut. I like the idea of temp fix with heavy weight oil. Tractor is out of warranty so I am on my own. Service tech indicated there is some kind of bearing preload required that means a torsion setting. I am getting the idea they simply don't have the correct torques settings. I am thinking I can do the repair, mic the shaft for roundness and properly torque the shaft. Otherwise, I am off to the selling dealer to drop another $380 for seal replacement with no gaurantees. Really should not have to worry about a leak on the frond MWFWD. Thanks very much for helping with the pdf.

Joe... appreciate the manual pdf. Unfortunately, it is only good for Serial numbers up to 610001. I am hoping the axle hubs are unchanged. That is what I was looking for anyway.

Contacted the JD dealer this a.m. They said they had indicated the housing may be damaged and they were hoping the seal would hold and save me the cost of a new housing. That part is almost $600. They will do labor for free but I still will now have well over $1k in the repair and 6 weeks out of service at prime farming time lost.

Stuck with this for now... Perhaps the part will come in this week and I will be back up and running by Saturday.