John Deere 4300 complete rebuild

[dfkrug]

Here is the PTO clutch, brake, and shift fork. If you look closely at
the first photo, under the letters "TO", you can see that the clutch is
missing one friction disc. How did that happen? If the clutch broke,
it is hard to imagine that only one disc of 9 were affected. I checked the
thickness of the plates for the brake and the clutch and they were both
in spec. I suspect that the last mechanic forgot to put in all the discs.

The 2nd photo shows removal of the brake assembly, after removing the
support bulkhead. The shift fork needs to be removed before the clutch
can be slid out toward the rear.

At $250, the clutch "pack" (9 discs, 8 plates) is one of the most expensive
parts of this rebuild. They are only sold as a pack.

[kebo]

Here I am removing the rear PTO cover. Nice big gears in there.

Oh my, look at the pieces of clutch friction disk in there! I picked
out enough fragments for more than one whole disk. There are probably
enough small fragment to fill a 2-oz cup. These are the fragments that
adhered to the suction filter above.

The PTO on this tractor is engaged mechanically and the rental yard has
had a bunch of them broken when the renter engages the clutch at
high RPM with a rotary mower attached. Sometimes the whole clutch
"basket" disintegrated.

All the more reason that no one should ever loan or rent out their tractor to anyone unless you know it's someone who is knowledgable about tractors and can be trusted to not abuse it! I occasionally see ad's on craigslist of peope wanting to rent their tractors for like $150/day. That will hardly cover the cost of any serious mechanical repair that might needed to due to abuse or negligence.

[dfkrug]

Keith, does your 790 use any aluminum castings in the rear? I think
that unit is still all-Yanmar.

[kebo]

To be honest, I haven't looked at it closely enough. I guess the way to tell is with a magnet??? If not, how do you tell? My tractor is about 70 miles from me now so it will be next weekend before I could look at it.

[dfkrug]

To be honest, I haven't looked at it closely enough. I guess the way to tell is with a magnet???

A magnet would easiest. I can see why some smaller tractors use Al, but
I was stunned to find the 4300 does. I am very curious what other
makers use Al for tractors over 2500 lbs naked.

[kebo]

Well, I can tell you that the 790 is only about 2100 lbs. It's probably the lightest 30hp diesel tractor in that class. That kind of bothers me now, maybe it does have a lot of aluminum in the castings?? I've not read of any recurring problems with broken housings or castings on the 790.

[dfkrug]

Now I am splitting the tractor. After removing all the parts necessary to
get the fuel tank out, there was little more to be removed before separating
the tractor at the bellhousing/engine connection (first photo). Splitting
was fairly straight forward.

The second photo is the torsional damper that bolts to the flywheel. This
item contains a sandwich of rubber and some springs to absorb some of the
vibrations between the engine and transmission. This tractor has no foot
clutch, so there is no clutch disc with built-in damping, as you usually have
with clutch-equiped tractors.

At this point, I can tell you that all of the rental company's 4300s experienced
problems with the damper and had the dealer replace all the tractors. I do
not know exactly how the dampers failed, but deere made good under
warranty. This little item is over $500 if you have to buy it!

In the 3rd photo, I have unbolted the engine from its subframe and attached
my engine stand bracket. That gives me another lift point, too, as the
rear engine lift hook is surprisingly missing. The last photo shows the engine,
now free, held up by my Kioti forks. Next: taking the engine apart.

[dfkrug]

Il ck my 4310 this weekend, also any chance u could post a good pic of that hood protector i want one to save my new hood.

Here is another photo of the deere hood armor. The arrow points to the
place where it pivots forward so you can open your hood. Closed, it rests
against the loader arms. The brush guard is integrated into the hood plate,
so you get rid of the stock guard that came with your loader.

If you lend out (or rent out) your tractor, it makes sense to have one of
these!

[dfkrug]

OK, now the engine is on its stand and the head is off. This one is very
different from the pre-EPA engine (also a 3TNE84) from my last JD955. The
oil pan is a heavy cast stressed member that the subframe bolts to. The
955 was a full frame tractor with sheet metal pan. The front gear case had
a crap-catcher plate bolted to it....that is why it looks so nasty...it was
packed with dirt.

The water jacket design results in a fairly thin-walled cylinder. So only a
.25mm (0.010") oversize piston is offered by deere. All three 955s I did
were bored for 0.5mm O/S pistons. Since I do not have a 3-4" inside
micrometer, I made a guage from a steel rod ground down to a point at
each end, and made to the wear limit of the O/S piston bore. At the worst
wear areas, I am right at the limit. Boring for liners would be the only other
option to save this block, if I can not make do with .25mm.

The head is pretty nasty, so I had it hot-tanked after removing the valve
train. I will be lapping to clean up the seats, but no seat cutting. The
valves are in nice condition. Getting the injectors out is often very hard.
One gave me particular trouble, so I removed one stud for better gripping
access. I will reuse these very expensive FI units.

[Wayne_H]

You know, I look at my 8 year old 4400, and wonder what the heck anyone could possibly do to a machine to trash it so much in that period of time. Even when I rent equipment I take care of it! KennyD and I have been inside my trans, and trust me, there was no large chunks like the inside of that one!

Regarding the aluminum axle, I guess you are sure it is Aluminum and not cast? Cast is not always magnetic I think too.

Good luck, in a few months it will look better than mine!

Wayne