4 Fitting Vs 5 Fitting Power Steering Valve?
Posted April 25, 2013 - 08:05 PM
MY understanding is that the power steering "head" (the part that the steering wheel hooks to) on the 318 deere has 5 connections? I picked up a jacobson greens king4 diesel mower (more on that soon...) that has a power steering system which LOOKS like the 318 one, but has only 4 connections on it... Whats the difference?
Also the 2 circuit spool valve on the 318 has a power beyond fitting that feeds the power steering system, correct? I want to upgrade the 316's single spool to a 2 or even 3 spool.
Can I use any spool with the appropriate number of ports, or do I need one with the power beyond fitting. Can a power beyond be added to a non-power steering spool?
Thanks for the help....
Posted April 25, 2013 - 09:24 PM
Any spool valves return port can be used as "power beyond", or simply a return line. But the 318's lift spool valve is supplied oil from the power beyond off the steering valve, then from the spool to the return fitting on the hydro. To use a 4 port steering valve, simply plumb the return line from the spool valve to the pressure input port of the steering valve, and the steering valve's return port to the return fitting on the hydro. When using a 4 port in this fashion, when dead heading the lift, ALL power steering will cease for that instant, but not a big issue at all. Best by far is a 5 port steering valve, so that the power beyond off the steering powers the lift circuit.
- twostep and tamar2112 have said thanks
Posted April 25, 2013 - 09:34 PM
Daniel is correct like usual, great explanation Daniel !! .
Posted April 25, 2013 - 10:15 PM
Thanks! I went and looked at the schematics for the hydraulics (in the manual) - has both new and old setups. So was able to "see it" but was wondering about the dead spot with the 4 port steering.
What if you rigged it the other way - with the steering before the spool? Would the spool only go "dead" when you were turning the wheel?
The spool before steering on a 4 port might be an issue say for snow plowing with a blade, but wouldnt think it would be an issue most of the time otherwise?
If I wanted to add a 3rd spool, I would use a 3 port spool from say a 420 or 430, correct? Are there any fittment issues aside from adding the extra lines? Does the 420 spool mount differently or is it too big to fit in the space, etc?
I got this nice little Kubota 600 diesel and the full power steering system from the Jackobson turf mower, and can probably use the hydraulic tubing as well for the lines. Just thinking my way through the possibilities for low cost fun....... It has a 5 port spool system on it, but is physicallly too big to fit on the little deere. Figure I can sell off the pumps and spare stuff to pay for what I need to get for the 316.
Posted April 26, 2013 - 08:30 AM
Sounds like a fun project!! Can't beat the Kubota diesel's.
Posted April 26, 2013 - 08:43 AM
Changing from a 2 spool valve to 3 spools is no issue at all if there is physical room. Plumbs into the same input & return lines. Just a matter of hoses for the 3rd spool section to implement.
I was told at a hydraulic shop not to put the steering valve ahead of the lift spool assembly because of back pressure against the steering valve when dead headed, but then he said the lower pressures of these GT systems likely wouldn't hurt the steering valves either. The drop in steering is not a big deal really, as most of the time when lifting you are reversing direction & not in a turn situation, and this time is just a second or 2 at most.
- Tennblue59 said thank you