4300 Tractor - front axle seal leak

[wrede]

I determined that my tractor has the ball bearing front axle with a snap ring to hold it together, and so replacing the seal should be easy. The first I thing I noticed upon draining the oil was that it was milky, suggesting some moisture in the front axle, but surely not much, as there is no indication of any bearing or gear damage. How could it get in there? I'll have to carefully flush it out with fresh oil.

The second thing is that the seal appears to be cocked in the housing, maybe a 1/16" at the rearward side, suggesting it was pushed out a little. Is it possible that the moisture in the oil allowed it to freeze and thereby pushed the seal out? Is this too wild a theory? Of course, the drain plug on the affected side has been swaged over, probably by a rock encounter, and I can't get it out. Should I drill it and use an extractor? Removing the axle housing was easy, but I haven't gotten the axle assembly apart yet. I have two snap ring pliers, but neither is the right size. Off to the tool shop tomorrow. It still looks like a simple fix, but we'll have to see what develops. BTW, the JD replacement seal is a new design, and is supposed to protrude about 1/16" when installed, which means it will take up essentially all of the hub to housing gap.

 

[Zebrafive]

Water is most likely from condensation, any idea how long it has been since it was changed?

Hard to give advice on the drain plug. A picture might help.

 

[wrede]

Front axle oil has never been changed. Hour meter is at 560 hours. Drain plug has a ~5mm hex key socket, and is perhaps 1/2" (12mm) OD. I may be able to hammer in a 5 mm hex stud, but that's for tomorrow.

 

[Zebrafive]

Front axle oil has never been changed. Hour meter is at 560 hours. Drain plug has a ~5mm hex key socket, and is perhaps 1/2" (12mm) OD. I may be able to hammer in a 5 mm hex stud, but that's for tomorrow.

How long has the oil been in the axle in real time, not hour meter time? I'll still bet water is from condensation.

Sounds like a good plan to get the plug out.

 

[Dutch445]

if you have a leak, in which oil can leak out,
moisture or water can also go in! depending
on conditions, expansion etc.

 

[wrede]

The axle housing, contrary to the repair manual information has one roller bearing and one ball bearing, and the assembly is pressed together and held with a snap ring. The inner bearing seats in a "cup" in the wheel housing, and so when it's together, the axle is supported at both ends. Getting it apart took a heavy hydraulic press effort, and the same putting it back together. The replacement seal is actually two piece, as I learned when it came apart. I've got it back together, and don't see any leaks. I flushed out the old oil, and can only assume it was condensation that caused the milky appearance, and apparently it doesn't take much moisture to cause that. I have never had the tractor in water, and so don't think it could have had water going in through the seal, which has a head of oil about 6-8" above it, as the wheel housing is completely flooded. I left the damaged drain plug as is, especially after twisting the 5 mm key right out, figuring I'd end up with another project extracting it. BTW, the tractor is almost 10 years old, and it was the original oil. The old seal looked okay, though it was in fact cocked in the opening. Thanks for the helping me out.

 

[defed]

when i got my 4300, the dealer told me all of the fluids had been changed. i never checked the front axle fluid before delivery, but when i did, it was white. i got the dealer to give me the oil to change it. one of my plugs was bashed up too. i drilled it and used an extractor. it wasn't TOO bad.

i had to change the knuckle seal about 2 months later.

 

[reasley]

I, too, have both seals failing on my 4300. The driver's die has been "seeping" for a while, so I put it on the back burner, then the other side all of a sudden started leaking a lot, so it's time. In the workshop manual, it says that there are two types of bearings: either the axle has tapered bearings or ball bearings and you are *supposed* to be able to tell by looking at the axle number which is supposed to be located near the housing where the dip stick is located. Those numbers are no where and I am assuming that the axle probably has the ball bearings. Any definitive way to know other than dis-assembly? Also, I looked up the seals this AM on the JD site and those dudes are almost $30 each. From what you say below, there is a reason for the price, I guess? (two-piece) Finally, I would be curious to know if there is variability across these axles that other owners have noted.

Richard Easley
Waco, Texas

The axle housing, contrary to the repair manual information has one roller bearing and one ball bearing, and the assembly is pressed together and held with a snap ring. The inner bearing seats in a "cup" in the wheel housing, and so when it's together, the axle is supported at both ends. Getting it apart took a heavy hydraulic press effort, and the same putting it back together. The replacement seal is actually two piece, as I learned when it came apart. I've got it back together, and don't see any leaks. I flushed out the old oil, and can only assume it was condensation that caused the milky appearance, and apparently it doesn't take much moisture to cause that. I have never had the tractor in water, and so don't think it could have had water going in through the seal, which has a head of oil about 6-8" above it, as the wheel housing is completely flooded. I left the damaged drain plug as is, especially after twisting the 5 mm key right out, figuring I'd end up with another project extracting it. BTW, the tractor is almost 10 years old, and it was the original oil. The old seal looked okay, though it was in fact cocked in the opening. Thanks for the helping me out.

 

[dfkrug]

In the workshop manual, it says that there are two types of bearings: either the axle has tapered bearings or ball bearings and you are *supposed* to be able to tell by looking at the axle number which is supposed to be located near the housing where the dip stick is located. Those numbers are no where and I am assuming that the axle probably has the ball bearings.

Have you scraped off the paint around the fill hole, Richard? The parts
book refers to at least 4 different front axles. When I posted my thread
about the hub and kingpin seal replacement, I noted that my very early
axle had a tapered roller bearing in the kingpin, and a straight roller
bearing on the hub (photo). My 2000 4300 has a date stamp, too, but
my 2001 has no date, just the axle part number.

You can take it all apart to see what you have, then order your parts...they
all should all be available in 3 days.

 

[wrede]

The dealer may be able to get the right seal based on the tractor serial number, but the axle identification on my 2001 was stamped in the machined flat around the dipstick, at the rearward side, but it was a little faint. Get a flashlight and hold it at a shallow angle to highlight the stamping, assuming it's actually there. The repair book says it's the ball bearing type, but mine had a ball bearing on the outer axle, and a roller bearing at the inner end. You'll need to have access to a hydraulic press, as mine took at least a ton of force (bottle jack type press) to get it apart, and the same putting it back together. The gear is on a tapered spline, and that may be the tightest part. The replacement seal cost $37 including tax, and came with instructions in 5 languages explaining that it should be installed about 1.5 mm (.060") proud of the housing. What it didn't say was that it was two piece, as I learned when it came apart. After installing the new seal (with sealant on the OD), you can put the axle back in, but be sure to hold the seal together as it is a tight fit on the axle surface, and will come apart unless you hold it. If I did it again, I'd be sure I had a piece of PVC pipe or something similar roughly the size of the axle seal ID so that as the axle is pushed in, or actually as the housing is dropped on the axle, the seal can't come apart. I was able to put it back together, and checked to be sure it was free to rotate. I used a bronze drift to tap the ball bearing back into place, and the hydraulic press for the gear and roller bearing. The snap ring has almost no play, and so you'll know when it's home. When you remount the assembly, remember that the inner bearing fits into a mating socket in the steering housing, and it should slide together easily, but you may have to wiggle it a little. I haven't used the tractor since due to the weather, but I drove it back to the "barn", about 200 yards away, and have checked it a few times in the last ten days and it is dry. If I had to do it again, I think I could do it in 3-4 hours, including flushing the oil, but it would have been a little quicker if I had been able to remove the drain plug on the failed side. BTW, the lower plug is an 1/8" pipe thread with a hex socket, which is 5mm, as I recall.

 

[AzChopp3r]

Hi folks, sorry to revive such an old thread but I have a leaky seal on my 4300 I posted about it here :http://www.tractorbynet.com/forums/parts-repairs/310404-jd-4300-mfwd-seal.html without any response so far probably because it is in the wrong area. I am in the process or researching this before I dive into it. I am fairly mechanically inclined and own all the proper tools, press, etc. just like to know what I am getting myself into before hand.



This is the MFWD that I have (S20BZ 107) and I have a leaky knuckle seal (#10)

Questions are:

Am I able to remove the 4 bolts and pull the entire knuckle/hub assy. off and place it on a bench? And in doing so would I need to reset the endplay again?

From what I can see, replacing this seal does NOT require pressing anything apart but replacing the hub shaft seal (#22) DOES.

So basically I plan to remove the 8 bolts holding #24 and remove. Remove cap #20 and split rings #19, #3. Remove spindle. Remove nut #14 and separate the two housings to get to the seal.

As for the wheel shaft seal, I need to press out the shaft #21 from the bearing and separating 21 from 24 to get to the seal.

What have I missed or where am I wrong? Anything else I need, sealant, etc.?

Thanks.

 

[defed]

i changed mine a cpl yrs ago, guess what, it's leaking again.

i don't remember exactly what i had to take apart, but i do remember having to borrow the special socket from the dealer to remove nut #14. i think everything was removed thru the bottom (cap #20), and maybe nut #14 holds the hub (#29) to the knuckle (#9). the nut is up in there a few inches, so the 'spanner socket' was deep. i think i left #9 on the tractor and just had the hub #29 off to get the seal in. when i get a chance, i'll check in the service manual since i have to refresh my memory for when i do mine anyway.

 

[AzChopp3r]

Thanks for the reply, I appreciate it.

Looking at the schematic, it actually shows a total of 3 seals. #10, 22,33. Unbelievable what they want for these seals. Total for each side is $121.76. So $243.52 for the rubber seals for the front end of my tractor. Not including shipping. Wonder if NAPA can cross reference these.

 

[defed]

i probably still have the receipt for when i did mine. i think all i used was the seal at the knuckle (10) and the cap (20).

if you have the original style caps, try not to wreck them. my originals have a steel lip that hits the housing when you push them in. the ones i bought don't, just a rubber seal. while the steel lip doesn't offer much resistance to getting pushed up into the housing, the rubber seal offers none, and is a horrible design in my opinion.

i once was moving dirt w/ a box blade. i had made a pile, which i then straddled (90 degrees from the direction the pile was made) to grade it. apparently when the front end went over the edges of the pile, and sunk in, the dirt pushed the cap in, tilting it, and all my oil leaked out. i didn't even know it happened until i parked it and saw the puddle. probably drove an hr in 4wd w/ little front end oil.

 

[wrede]

I have not had a problem with the knuckle seal, that is, the vertical shaft that runs between the differential drive shafts and the wheel hub. I did have leaky wheel hub seals. There are two designs, and the serial number on the casting next to the dipstick determines whether the axle shaft is held on with a highly torqued nut, or snap rings. Mine is a 2001 model. When the first leak occurred, and I looked at the manual, I assumed that the snap ring on my unit would just pop off and I could pull off the bearings and gear. Forget it. It was quite a press load to get it apart. I had a 20 ton cylinder at the limit, and it wouldn't budge. I then gave it a rap with a big hammer. Bang! The old seal was a face seal running against the wheel hub surface, which left a slight groove. The new seal is a different design, no explanation from J Deere, with a two piece assembly where the inner and outer portions are a light press fit in the housing. The seal is between the mating two halves of the seal, not to the wheel spindle surface. I was nervous about putting the new design in place without instructions, but it has held up well, and I soon had to do the other side. I have about 300 hours on the new seals, and they're dry. If you need the repair manual, I have an e-file copy and could send it to you. Incidentally, the seals are very expensive, but also very special. I suggest you do an internet search to see if you can find them cheaper, but make sure you get the new design, as it seems an improvement.

 

[AzChopp3r]

Would need a manufacturer and part number to see if the seal is made exclusively for JD or it can be cross referenced. Im thinking I had better get my wallet ready....

 

[wrede]

I'd suggest checking online sources. I purchased my wheel hub seals at the local Deere dealer, and remember they were expensive. Again, the replacements I got are different than the original, in that the rotating oil seal is between the two seal halves, not against the hub or housing, as in the original.