John Deere 4300 complete rebuild

[dfkrug]

The tractor won't come apart.

Did you disconnect the MFWD drive shaft? Both it and the main drive shaft have roll pins you have to remove.

You are following the steps in the service manual, correct?

 

[JustaTreefarmer]

Now that the kingpin is out, I can get the last two housings apart to get
at that blasted kingpin seal. Note: my hub seal was leaking badly, but my
kingpin seal was not. I decided to change the latter seal out anyway
because I wanted to assess the condition of the other bearings. Happily,
JD uses large tapered roller bearings in there, and they are in fine shape.

To get these last two housings apart, you can see (first photo) a large
nut with four slots. Special tool alert! :-( I am not a fan of special tools,
but nevertheless, I had to use one. I first used a large screwdriver to
retract the staking collar (not visible). To make my tool, I found a chunk
of schedule 40 pipe, which has a slightly smaller ID than the OD of the
nut. With a die grinder/carbide cutter tool, I beveled the edge, then
welded two small beads on opposite inside edges. Now I can grab two of
the nut slots and use a large channel lock pliers grab the pipe and unscrew
the nut. It worked great, and the 2nd photo shows the results. The 3rd
photo shows the staking collar, nut, and roller bearing.

Finally, I removed the large seal with my trusty tire iron. Voila.

Assembly, as they like to say, is a reverse of this process. (500 times
easier, too.)

A final note on DIY replacement of these seals: this was tough, and it taxed
the limits of my abilities and tools. Other seal replacements I have done
on MFWD axles were many many times easier. I can not recommend that
MOST people attempt this project for this tractor. I saw this process as a
personal challenge.....others may only be frustrated.

Just goes to show you your contribution to the cause. My left seal was leaking while I watched and read your progress on this at the time. I used this to tear mine down and replace the seal.

My right seal is bad now and I dug up your thread to remind me of the process before I tear into it.

Thank you Greatly!

 

[dfkrug]

I had to re-read it myself. Last fall, I replaced front axle seals and bearings on a Kubota B20. MUCH easier!

 

[JustaTreefarmer]

I had to re-read it myself. Last fall, I replaced front axle seals and bearings on a Kubota B20. MUCH easier!

You didn't by chance do a "how to" on the 4300 rockshaft seal replacement?

I'm interested in studying up on that as a stand alone repair. Mine won't stay up when tractor is shut off and lowers and lifts when running

 

[dfkrug]

I did not replace the piston seal in the 3-point cylinder. I did open up the 3-pt valve, but did not re-build the valve itself. I did remove the 3-point arm upper pivot shaft (rockshaft), but would have to go back to see what I did.

 

[Gregster613]

dfkrug....As usual, a "Great" refabricating adventure explained in exacting detail!! Tractor looks superb and better than new even! I don't own a JD but I sure do enjoy following your processes in dismantling and reassembling. Thanks much for this and past threads. Just love to read about the process. I sure do envy your skills and fabricating tools, thoughts. Thanks for sharing. Keep it up. Greg

 

[JustaTreefarmer]

I did not replace the piston seal in the 3-point cylinder. I did open up the 3-pt valve, but did not re-build the valve itself. I did remove the 3-point arm upper pivot shaft (rockshaft), but would have to go back to see what I did.

As a follow up, the issue was not the seal. The metal mesh inline filter in inlet fitting to the RCV had blown into the valve itself. Evidently this is/was a known problem that they corrected in the 4x10 versions by eliminating the mesh and replacing it and the feed line from the RCV with two chunks of tubing with fittings and a screw on inline filter.

 

[dfkrug]

As a follow up, the issue was not the seal. The metal mesh inline filter in inlet fitting to the RCV had blown into the valve itself. Evidently this is/was a known problem that they corrected in the 4x10 versions by eliminating the mesh and replacing it and the feed line from the RCV with two chunks of tubing with fittings and a screw on inline filter.

The inline mesh filter in that location was itself a bandaid effort to protect the 3-point valve. I have not seen anything like that in that location on other tractors. I recall that both of the steel mesh inline filters on both of my 4300s had become displaced by the flow of oil, but not enough to dislodge the mesh and wash it downstream into the valve. That seems to be what happened in your case.

If I still owned a 4x00 or a 4x10, I would eliminate the filter, but maintain a very clean hydraulic oil system.