3 point lift capacity on MF 1655??
Posted December 13, 2010 - 09:48 AM
I understand what Bob is saying here but I don't know if you understand hydraulics well enough to apply his words to your situation. There are two issues here. One is the hydro pump itself and the other is the three point hitch.
Relief valves are installed in pumps for the same reason we install fuses and circuit breakers in our homes. Those items protect things that are beyond the source of the supplied power from damage. Bob is rightly concerned that the engineers at Massey decided to limit the pump pressure to a mere 750 PSI so as to protect the hitch components from damage due to bending or even snapping.
Coincidentally, the CAT O 3pt hitch used on the Case GT also has a relief setting of 750 psi. However, the nearly identical CAT O hitch used on the 600 series Case FEL tractors has a 1000 PSI setting. The 600's are much heavier in operating weight plus they have the counterweighting effect of the bucket sticking out the front.
My biggest concern here is not for the hitch components or the pump itself but rather for whether there is a test port to install a pressure guage in or not. I would also want to know if there is a factory shim kit available plus a service manual that would instruct me how to proceed. Sometimes only a few thou can make too big a difference in max pressure so one has to be ultra-cautious when playing around with relief settings. A guage is an absolute must or you won't know if you have hit the target or exceeded it by a country mile.
Hydro pumps are complicated and quite expensive to replace or even repair so make sure that you fully understand how to do this in advance of taking it on.
Posted December 13, 2010 - 10:00 AM
Posted December 13, 2010 - 11:25 AM
Hydriv, yes there are ports for gauges. But Luke, unless something goes wrong, I advise against messing with any settings. I'm a firm believer in "don't fix what ain't broke"!
Luke, you will note that I mentioned that I haven't tried to change the relief setting in a previous post. I've operated my 1655 for 28 years with out changing it for just the above reasons posted by hydriv and olcowhand.
Posted December 14, 2010 - 10:00 PM
Posted December 15, 2010 - 02:35 AM
If you want the pressure for lifting a specific implement on the 3PH, install the 'T' in the rod end port of the 3PH cylinder. For the mid lift it goes in the cylinder base end port I believe, I took mine off many years ago since I can't use it with the FEL installed and I forget which end does the work.
I suggest at least a 2' long x 1/4" 5800 psi hose hose on a 2000 psi guage to get the guage out to where you can watch it and operate the controls comfortably. Take care with the routing of the hose. If you want to check the transmission pressures, you should sub in a 5000 psi guage. The reasons for the higher pressure guage is that the cross-over relief valves are factory set at 4500 psi to protect the system from extreme shocks even though the system operates with 1500 psi relief valves, and guages read most accurately in their mid range. The hydro will develop maximum pressure at idle, it just doesn't move much oil. If you chain the tractor to an immovable object, at idle and sufficient forward pressure on the pedal, it will develope max pressure. By advancing the throttle to its normal operating position and trying again, you can discover the pressure that will result in wheel spin at that rpm and on that drive surface or condition (dirt, grass, gravel, wet or dry, etc.).
Edited by TUDOR, December 15, 2010 - 02:44 AM.
Posted December 15, 2010 - 07:19 PM