replacing 5 valve bank with a three valve and a 2 valve bank connected

[quietrangr]

Hello, everybody,
That aftermarket float looks like a lot of extra plumbing. Will have to think about it. The float kit looks easier, but would be hard to get; Surplus Center doesn't have them. Thanks for showing me where to find that manual, JJ. Could come in mighty handy.

 

[Tx Jim]

J_J
I'm asking not arguing. Doesn't spool require more lands for float than a plain old 2 position valve or can float detent spring be added to any spool valve to add float option?? Why does this state spool with float will only function in a certain location in valve body?
Thanks,Jim

 

[J_J]

Float is an option, whether it is installed at factory or in the field. It also has to go in a certain bore of the valve.

The float spool does have a different configuration, and you can have float with out detent also.

Once a spool is installed, it is left in place.

You may have to have a special spool for float to work properly, and the detent mechanism is what keeps it in float.

In your above illustration, there are different spools for the valve position, it can be a float spool or not.

Most loader valves will have float and detent.

 

[Tx Jim]

J_J
Thanks for confirming float spool has a different spool from regular valve.
Jim

 

[quietrangr]

I'm getting a two valve Cross monoblock tomorrow, and I found the following quote at Cross for converting to closed center. Not sure what they mean by "the relief on the handle end of the valve must be replaced with a no relief plug." Are those bolt heads on top of the block actually the relief valves, and they are to be removed and replaced with the no relief plug? I thought there was a single relief for all valves on the monoblocks. Would I need to replace both of those relief valves with no relief plugs, and then do I even have a relief valve functioning for those control valves? I'm confused

From Cross:
To convert an open center valve, remove the short conversion plug and replace it with the closed center plug as shown. The relief on the handle end of the valve must be replaced with a no relief plug. (See table for part numbers.) Failure to replace the relief will result in chattering caused by the constant bypass of oil and will build excessive heat in the system. An outlet must be plumbed to the tank to dump the oil from the return passage

 

[J_J]

If our tractor has a closed system, the relief is by the pump.

Replace each valve relief with no relief valve and install the closed center plugs in the valves.

 

[Tx Jim]

If our tractor has a closed system, the relief is by the pump.

There is no relief valve by the pump on a JD440C. There is a stroke control valve in the pump that controls whether pump actually pumps oil or doesn't pump oil.

 

[J_J]

If the relief is not on the valve , where is it.

Just about every hyd system will have a relief valve.

 

[Tx Jim]

JD ag hyd systems have a priority(pressure control) valve that ensures power steering get the last psi of pump output. Some models such as rowcrops have brakes included but utility tractors aren't included. Other than that priority valve the only other valve with relief valve(thermal relief) is the rockshaft control valve. Scv's & FEL valves don't require a relief valve because if stroke control valve in frt pump is functioning properly hyd psi will not exceed stand-by pressure. As I've previously stated my experience is with ag tractors and industrial tractors are a little different and some ind backhoe & FEL valves could have relief valves. I'm confident there isn't a relief valve close to frt hyd pump on a 440C.

 

[quietrangr]

Thanks guys. Yesterday I got a Cross 3 valve bank and a two valve bank, one barely used, one never installed, (craigslist.) I ordered the closed center conversion kits from northernhydraulics this morning. Surplus Center doesn't have them. Not sure, but I was told the pump had a 1750 relief valve that works on the whole system. Not sure if the Ag and Forestry machinery use the same system. I know the steering does get priority on my machine, and there is relief somewhere. I can feel it on the log loader and on the steering. I will let you know how everything comes out. Without relief, wouldn't everything blow up?