4300 hydraulics weak at first after setting for a few days

[larboc]

Weird problem started with my 4300. When I let it set for a few days it will barely pick up the loader. When I go to pick it up, it drops as I pull the lever back until I have it all the way back. Then it will lift, but very slowly. When I return it to center it drops a little then stops. Doesn't have much pressure either as it can't lift much more than an empty bucket and it can't lift the front end.

After running it up and down for awhile, it all of a sudden goes back to normal and works fine the rest of the day.

Plenty of fluid, I replaced the filter and hydraulic oil with OEM deere hytran low vis and deere filter.


Guesses?

 

[kennyd]

I would suspect the rubber "manifold" on the return line at the pump, they are known for craking and letting in air. IIRC they are only $20 or so and fairly easy to replace.

Sorry I can't post a link or picture right now, but if you search manifold in this forum you should find some.

 

[larboc]

Thanks, I'll check that. Are you talking about the one that connects the metal tube to the back of the pump on the left side of the engine?
I didn't see anything in a search.

 

[larboc]

Ahh, this thing.. John Deere Original Equipment Manifold M134346 | eBay
M134346

I'll check it out. Looks similar in design to the one on the rear pump on the x55 series tractors that tend to do the same thing.

 

[kennyd]

Yup, thats it...
Even cheaper at GFP, especially if you use the GTT discount code and or add more stuff to get the free shipping.

Green Farm Parts: John Deere Parts Online at Discount Prices

 

[larboc]

Don't think it's the manifold.
Not a single sign of a drop of oil anywhere near the manifold. Also, the power steering works just fine when this condition exists. Sometimes it can take 5 minutes of run time before the loader works properly. I can't imagine there would be enough air in the suction line to cause a problem that long on an open center system.

 

[jenkinsph]

While it may be free of any oil leaking out on the external surface I would still check into this. It is under a slight vacuum under normal operation with engine and hydraulic pump sections turning and also when you stop the engine and the oil is being drawn by gravity back to the sump. I don't think this manifold is ever under pressure. Don't think you have a transmission pump charging this line on your tractor.

Pull it off and see if it is pliable without any cracks. You could tape it up if you suspect a crack and reinstall it while waiting for a new one to arrive. That might help you determine if this is the problem.

Not knowing your specific tractor I would check for any leaks between the pump and lines to the sump.

About the five minutes, if the air leak gets a little worse it might not ever prime the pump. All the time you are operating without the proper lubrication.

 

[larboc]

While it may be free of any oil leaking out on the external surface I would still check into this. It is under a slight vacuum under normal operation with engine and hydraulic pump sections turning and also when you stop the engine and the oil is being drawn by gravity back to the sump. I don't think this manifold is ever under pressure. Don't think you have a transmission pump charging this line on your tractor.

Pull it off and see if it is pliable without any cracks. You could tape it up if you suspect a crack and reinstall it while waiting for a new one to arrive. That might help you determine if this is the problem.

Not knowing your specific tractor I would check for any leaks between the pump and lines to the sump.

About the five minutes, if the air leak gets a little worse it might not ever prime the pump. All the time you are operating without the proper lubrication.

But both pumps are fed from the same manifold, if the front pump (power steering?) is getting fluid the big rear pump would have to be as well.

 

[beenthere]

I'm going to look into changing out that manifold hose, just as a precaution for any future problem. I'd rather not have it part of a future problem, if I can prevent it. Thanks for the heads up.

 

[jenkinsph]

Will the three point hitch lift an implement when this happens?