My 317 JD has an operating pressure of 3450 PSI. I have an attachment left over from the tractor that says not to exceed 3000 PSI. Is there some sort of a pressure relief I can put on the machine that I can limit the PSI with this attachment? What do I do? I really need to be able to use this attachment. Thanks
Will the hydraulics explode if I use it? I spose I could replace lines/cylinders.
What kind of attachment is it?
grapple
nedly05, I don't know that product but on most attachment circuits there should be a relief valve in the control valve or upstream of it to control that circuit at a lower pressure than main relief valve. Your dealer may be able to supply a valve with a different operating range if the current valve can't be adjusted lower than you need.
Thanks Wulf, I'd like to get something like that so I can adjust it down for the grapple, then back up for other attachments.
I would not sweat 400 psi. I would run it.
I was thinking the same thing. I doubt it will make much difference.
Well 400psi (28.5 BAR) is not really that much but if your worried then get some pressure reducing valves (PRV) for the circuit. If you know a good hose man then the leak off side of the valve's can be T-Linked into the returns with Check valves in place. $$$ The PRV can be adjusted to the correct pressure. TBH I would only bother if I was dropping the Pressure by 100 BAR or more. Ross
I have seen this many times, using a tractor attachment on a modern skid steer. The PSI limit is not necessarily for fear of blowing out seals, but for avoidance of bending/breaking parts. Hydrostatic skid steers have more pressure and cfm fluid flow than tractors, so care is needed when operating attachments designed for less. If you don't force the grapple, you can take the advice above and not have a problem. If pressure relief was necessary, you would have to have a by-pass on your control valve. Spool valves generally regulate the flow to prevent extreme pressure fluctuations. Most attachments use single-wire braid hose which has a working pressure of around 3000 PSI.
Thanks guys, lots of good info, It makes me feel a lot better to hear all of this. I e-mailed the grapple mfg, no response yet, I e-mailed www.tracksplus.com and the quoted me right around 1400 for tracks for my machine, for all of the research I have done I think they are a hell of a set of tracks for the money. Man do I love this machine, cant wait to get the tracks!!!!!!
Did you ever get a set of tracks, if so how are they working out for you.
I'm not familiar with the machine but I haven't seen a hydraulic circuit design that didn't include some kind of circuit relief. However you stated that you wanted to be able to easily change that pressure when installing other attachments. We used to obtain and install what was called a Drac valve. I don't know if that was the name of the manufacturer or a type of valve. It was a block of steel or aluminum that had cartridges that you could set. They were cross over reliefs. Pressure would be bled to the return side of the circuit. You could mount one somewhere on the grapple so that that only time the pressure would be affected is down stream of the machine quick connects. There should be a hydraulic component supplier in your area that can help you out. Good Luck?