Gresen 25p hydraulic valve

Best Practices for Gresen 25p hydraulic valve

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I haven't taken it apart but have one on the old Prentice, 5 sections. I have a pdf of the manual but it is out of support and beyond what I can fix. We were having a cylinder rebuilt for the Lull at a good hydraulic shop and they can rebuild it so I think that's where this one is going at some point. If you need the manual pm me your email.

When i was born the 25p was a workhorse valve, quite a relic now but im pretty sure they made reamers and sleeves and oversize spools for them at one time.  back when brake shoes were relined and distributors rebushed.Nothing special about taking it apart that i recall.

the best thing to do is find a tandem pump. you will like it much more than having a single. that valve bank should have a mid section. think of it as 2 separate hydraulic systems. 1 for each section of the tandem pump. to change it to a single pump. take the midsection out. you will also need a new thru bolt kit. because its going to be shorter and new orings. then the trick is stack all the valve sections with orings in place and install the thru bolts. a barko 80 was a pretty fast smooth loader with a single pump it will not be . gresen is now owned by parker

I agree with what snowstorm said.  The tandem pump dedicates sufficient but not excess flow to each motion.  When you go down to a single pump, sizing is a perpetual compromise.  You are either sized for it to work well going slow and precise, or well going fast.  The flip side is itll either be a slug when youre in a hurry or be too jerky when you need to inch over. Or a half way that is lackluster at everything.  Also your governor may end up being very active.If youre determined to go to a single pump and valve block, consider going to an on the fly hand or foot pedal throttle.  My old bobcat finally grenaded the hoof governor few years back and i put a hand throttle on it like how new cat skidloaders are these days.  Its much better in my opinion.  Runs at idle until i need more then it gets exactly how much more power i need.  I hated the steady state governor that was always lugging or screaming and never right. Good riddance.

My plan was to run  the pump off an international C153 4 cyl power unit. It will cost me about $100 to put a 20GPM pump on it and about $600 for a tandem pump. For now I will run the boom and stick together off the 20 and then use the 5GPM engine pump to run the clam. Will see how it works. Just need it for  stacking logs at the landing, non production. This summer I used my B414 to stack logs but it would only get about 6' high.I can see the benefit of a tandem pump forsure but like anything it comes down to time or money.

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main boom and swing were usually on 1 section of the pump stick and bucket on the other. just buy the tandem pump or have a pump section added to what you have. each should be 25 gpm. most of the time its cheaper to do it right the first time

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