Multiple hydraulic problems JD 4300 HST

[roquefortnight]

Really appreciate all the helpful replies! I think I'm going to drain the fluid tomorrow morning, check for possible loose connections, and either go to the dealer for replacement filters and fluids or if I don't find anything obvious I'll call and see what they say.

When I saw that "manifold" I thought the solution was at hand: the rubber had softened, collapsed and was restricting flow. But looking more closely it seems to be an injection molded plastic part that happens to look like it collapsed!

I did read that 4200 thread before I posted with my question. I'll see if I can find one of these high-pressure gauges and put together an assembly to test with, but I suspect (hope) I'll have a clearer idea of what's going on by day's end.

I'll keep checking this thread, and will give a progress update when I have something to go on. Many thanks.

 

[roquefortnight]

Condensation is another possibility. It probably got up to 34 today, which is about as warm as it's been in a while. But since the problem worsened only after a few hours of work, I doubt that icing is the problem. It's a good thought, though, especially since these hydraulic lines go every which way and could lose enough heat to prevent thawing. The weather's supposed to be pretty mild the next few days, which is good for some things (not freezing me or the tractor too bad), but introduces its own misery as compensation (wet snow sticks to everything, gloves get soaked, etc).

 

[RoyJackson]

There is a thread from just several days ago here on a JD 4200 on which the loader would not work.
http://www.tractorbynet.com/forums/hydraulics/164131-john-deere-4200-loader-slow-4.html#post1892726

That's a great link, Egon. I forgot all about pressure relief valves in the system.

 

[kennyd]

I would check te rubber "manifold" on the hydraulic pump. The suction line hooks up to this manifold. I have seen some of these develop a crack that will suck air. It is high enough that oil won't run out when not running. It is #2 in the diagram. Also check hose #8 for tight clamps.

Agreed. Fluid will look "foamy" while the machine is running.

 

[roquefortnight]

I would check te rubber "manifold" on the hydraulic pump. The suction line hooks up to this manifold. I have seen some of these develop a crack that will suck air. It is high enough that oil won't run out when not running. It is #2 in the diagram. Also check hose #8 for tight clamps.

This is definitely a part of the problem. The part is rubber, not plastic as I had guessed, and it is collapsing. I don't know why I didn't see that before. Thanks for the suggestion.

 

[Egon]

This is definitely a part of the problem. The part is rubber, not plastic as I had guessed, and it is collapsing. I don't know why I didn't see that before. Thanks for the suggestion.

Surely hope Kenny's advice:thumbsup: will solve the problem.

 

[roquefortnight]

After all that, a fluid and filter change and cleaning the pickup screen restored all my hydraulic functions. Even the steering seemed better, though I'd be surprised if that problem is fixed, since I had already done the above when that problem developed. Anyway, I know more about my machine's hydraulics and will remember the other suggestions should anything similar happen again. I think I'm also going to keep a complete transmission service kit handy in case this ever happens again.

Two other pieces of metal came out of the main transmission drain when I opened it, similar to the others I had saved. The pickup screen was cruddy, but not with big chunks of anything. Looked more like lint to me (maybe metal "lint"). I washed it in kerosene and scrubbed it with a toothbrush and blew it with compressed air, but I couldn't get it as clean as I would have liked. If that part isn't too expensive I might get another to have on hand as well. The guy at the dealership didn't know what the metal pieces could be from, but said perhaps they were fragments of a servo that was failing. I've got something else to research now, as I don't even know what a servo is. I also found out they've got a discount on parts and labor, and free trucking for most of this month. I'm overdue for my first engine valve clearance check, and while I've done such things on cars and motorcycles I don't have the specs or procedures for this job. Has anyone on this forum done it?

I also have a leak in one of my front spindle assemblies (I think that's what it's called). Don't know what's involved in that either: any suggestions?

Of course I'm totally happy with how this has worked out (knock on wood). It was a great day for working outside: neither too warm and sloppy nor too cold, and my wife was here to take the full one-gallon buckets (the biggest container I can get under the drain hole) while I held my thumb over it. Making the job a lot easier: it's about seven gallons of fluid, as you all must know.

I'm glad I posted my question here, and sincerely thank those who offered advice.

I noticed that I get logged out pretty quickly and have to re-log in. (Learned to copy my comments and save them pretty fast) Is this normal for TBN, or is it my browser settings?

 

[Egon]

Good Show:thumbsup:

Think about buying the technical manual.

 

[kennyd]

This is definitely a part of the problem. The part is rubber, not plastic as I had guessed, and it is collapsing. I don't know why I didn't see that before. Thanks for the suggestion.

Well to late now...But if you had wrote this before I would have told you that the suction screen was blocked for sure!

Is the material removed definitely metal? Could it be friction material (like from a clutch)?


I am not sure what he was referring to either by the term "servo"

 

[kennyd]

I noticed that I get logged out pretty quickly and have to re-log in. (Learned to copy my comments and save them pretty fast) Is this normal for TBN, or is it my browser settings?

Are you checking the "remember me" box? Will your browser accept cookies?