2550 Front Hydraulic Pump Leaking

Gents, I'm back! My hydraulic front pump on our 2550 Deere is leaking on top between the pump and the pump cover. It's a pretty significant leak (as evidenced by the broad trail of fluid I left on the road yesterday). All the bolts I can reach with the pump on the tractor are tight.

Long story short: John Deere's parts site is awful. Problem in this case is, their diagrams print in such low quality that you can't make heads or tails of it, and I can't see a way to print just the diagram in high definition. I am in need of the "exploded" diagrams for the hydraulic front pump. After looking at the parts site, there are two different pumps that "look like mine." Is one an OEM one and and the other an "aftermarket" one? How different are they?

I would need to check the model number on the pump to let you know which one I have, if they're different enough "to matter" (I'll do that tomorrow).

Also, this pump has also been rather noisy (a loud clanking at idle--it seems to go away or almost go away whenever the hydraulics are "called upon," like for the loader, steering, or 3 point lift) for a good long while now, even after us fixing a hydraulic issue in one of the SCVs last fall (posted about here, and after which the hydraulics ran MUCH smoother until now), and being certain about fluid level (HyGard). Could the noise be related to this leak (I have my doubts, as the noise was going on before the leak started--I guess the issue causing the noise could have led to this leak), or a symptom of another hydraulic issue?

To let you know, the tractor has a 245 loader, plumbed "as it should be", according to you guys. It also has the hi-lo shifter.

What do you suppose is going on to cause this leak? Seal broken between the pump and pump cover?

Thank you all for your help, fellas!

Should have specified--I have the "40 CM3" type pump, not the "23 CM3" type.

Sounds like its due for an overhaul,the swash
plate prolly wore and the radial pistons are not
seating good is usually why they chatter at low
speed no load,most of the time before chatter
gets worse higher speeds they blow oil out like
yours did.
However i have seen other things cause that too

(quoted from post at 06:04:56 07/15/19) Sounds like its due for an overhaul,the swash
plate prolly wore

Click to expand...

JD piston pumps such as the one on 2550 has "no swash plate" to wear out.

(quoted from post at 23:55:52 07/14/19) Should have specified--I have the "40 CM3" type pump, not the "23 CM3" type.

Click to expand...

Sounds as if o-ring(key 37) has failed. How many hrs on the speed-hour meter. New aftermarket pumps are around $1000

I forgot to mention to check for worn pump drive coupler making the noise.

There are many o-rings between that cover and the pump housing. Over a dozen as I recall and any one of them can cause a leak. I would
just buy a seal kit, take the pump apart, and reseal it. Deere uses two series of pumps. German design and USA design. You have the USA
design. They came in several sizes and were originally expressed in cubic inches - not this cubic centimeter metric nonsense. You have a
2.4 cubic inch pump. Very common. The main shaft in it is supported by adjustable cup and cone bearings. So you take it off, check main
shaft end-play before removing any bolts. If it is good - then no future bearing shimming needed. If too loose - you must tighten it up
with shims.

The rest is pretty straight forward. All the USA pumps go together the same. The clacking you hear is likely your stroke-control-valve and
seat. It is a normal wear item. Buy a seal kit, a new stroke-control-valve - and you will likely be fine.

I will note that Deere had many issues with the 8 piston nut-caps leaking on early pumps. They are all accessible on the outside of the
pump. Deere's fix was to put a teflon sheaf over each o-ring before installing.

Deere German pumps do not have adjustable bearings and come in small sizes of .7 or 1.4 cubic inches (11.5 or 23 cc).
Deere USA pumps come in 2.4, 3, and 4 cubic inches (40, 50, and 66 cc)
Deere also made a four-piston USA pump that was just have of a bigger one.

Thank you all for the replies. I don't mean to muddy the water with the following information, but it may be pertinent to the conversation:

On another recent post (https://forums.yesterdaystractors.c...amp;postdays=0&postorder=asc&start=30), it was mentioned that a leaking loader valve can throw the hydraulics into chaos.

I felt those messages were directed right at me personally haha!

The loader on this 2550, while I believe it is "plumbed correctly" as stated above, has a leaking valve. Could this have caused the pump seals to fail as they did? Or is it just "one of those things" you deal with with 40 year old machines? In either case, I will be tackling that leak as soon as I get the pump going again.

Someone asked: The proofmeter shows ~7100 hours. I cannot be certain it's accurate, but I believe it's close.

Thanks again!

There is nothing anywhere on or in the tractor outside the pump that can cause the main pump to leak other then mechanical damage from
debris in the oil or extreme overheating.

The pump has its own protection system so it cannot exceed PSI limits.

A leaking loader valve will just result in oil leakage and that is all. That is, unless you have a convertible valve which Deere used on
some loaders in the 80s-90s. A convertible valve works with an open-center or closed-center system. Your Deere has a closed-center. If
that valve is a convertible type, and the conversion plug in it blows its seals - then the hydraulics work awful and overheat. Plus the
tractor tends to get very hard to start and burns up starter motors.

After our "local mechanic" came to take a look at the pump and heard it run, it looks like our best option is a new pump. Where might a fella find a good aftermarket one for the best value?

Also, a local scrap yard has a couple of junked Deeres on his lot--how many other model pumps are compatible with my 2550's set up?

Here are the numbers off our current pump:

ROPVEA1023324
RP1040J0F0100