JD 3050 spool valves leaking internally ? Repair ?

Both double acting spool valves both appears to be leaking internally.

We put an oil pressure gauge on each of the 4 outlet connections in turn and on all 4, pressure builds slowly( 10 secs approx) to approaching working pressure with the lever in centre position.

We have had the wheel off so that we could see clearly what was happening and the actual rod mechanism appears fine with the valve centralising ok. No amount of waggling the levers stops it leaking and in the centre position everything feels free with no pressure on the lever working the valves.

No external oil leaks.

Can the existing spool blocks be serviced to stop the problem , or is the only solution new blocks.

There is a bottom block and 4 leaves on top.



3050 has done 10-12,000 hrs but in fair nick and runs well.
 
Last edited:

Tractortech

Member
Location
Cumbria
Now Then.
Spool valves are rarely 'zero leak'. If you have a pressure gauge in the coupler, it won't take much oil volume to show pressure.
Unfortunately, to put new valve slices in will be at least £1000.00.
What is your actual problem?? I've tested many such tractors but I must admit I've never looked for a leak in the middle position..
If you can't connect a hose with the engine running, just stop the engine..

As a little edit, I see a new valve slice retails around £540.00 , That's kinda expensive.
Vapormatic valves however, are £144.00, a bargain I'd say.
There's nothing you can do with your current valves to improve things..
 
Last edited:
Now Then.
Spool valves are rarely 'zero leak'. If you have a pressure gauge in the coupler, it won't take much oil volume to show pressure.
Unfortunately, to put new valve slices in will be at least £1000.00.
What is your actual problem?? I've tested many such tractors but I must admit I've never looked for a leak in the middle position..
If you can't connect a hose with the engine running, just stop the engine..

As a little edit, I see a new valve slice retails around £540.00 , That's kinda expensive.
Vapormatic valves however, are £144.00, a bargain I'd say.
There's nothing you can do with your current valves to improve things..
Will pick a 21 ft slurry stirrer up while in neutral ( top link attaches to a single acting ram ),so cann't set the stirring height for more than a few seconds. Floor of forage box creeps all the time. Jiggling the lever wont stop it.

The bit that seems odd is theproblem has developed on both spools at more or less the same time.

So there are no O rings to replace ?

Nick Young has these
2784 SELECTIVE CONTROL VALVE (TOP) PT36-1007 AL34593 £135.00
and I need 4 !
 
Last edited:

DrWazzock

Member
Arable Farmer
Location
Lincolnshire
It’s a real enough problem. Trailers creeping up when empty. Round baler door opening half way through bale formation. One reason we went to tractors with open centre hydraulics.
 

DrWazzock

Member
Arable Farmer
Location
Lincolnshire
I’d try a seal kit first. Strip them down carefully on brown paper. I’ll bet there is a seal kit from JD if they delve far enough in the system. O ring sizes will be critical to success so get the right ones not “looks near enough.”
 

Phil P

Member
Arable Farmer
Location
North West
I’d try a seal kit first. Strip them down carefully on brown paper. I’ll bet there is a seal kit from JD if they delve far enough in the system. O ring sizes will be critical to success so get the right ones not “looks near enough.”
As @Tractortech says there’s no internal seals just the ones on the ends of the valve to stop oil leaking out. The valve is just a very tight tolerance fit, chances are they are worn inside the housings and oil is seeping past. It will be a case of replacing the valves or the cheap fix of putting a stop tap on the pipe to the op’s hydraulic ram.
 
As @Tractortech says there’s no internal seals just the ones on the ends of the valve to stop oil leaking out. The valve is just a very tight tolerance fit, chances are they are worn inside the housings and oil is seeping past. It will be a case of replacing the valves or the cheap fix of putting a stop tap on the pipe to the op’s hydraulic ram.
Thanks for the answer
but I don't really like it !
 

Phil P

Member
Arable Farmer
Location
North West
Thanks for the answer
but I don't really like it !
I’ve known the brakes go and filings in the oil scores the valve housings! They either seize up or leak after that so pretty much knackered if its happened! Could just be worn out with age as well, they’re always a pain for holding a little bit of problem in the system.
 

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