Jump to content

Nominations for Tractor of the Month
Garden Tractors and Parts on eBay



Photo
- - - - -

3 point lift capacity on MF 1655??


  • Please log in to reply
20 replies to this topic

#16 hydriv OFFLINE  

hydriv

    Tractorholic

  • Validating
  • Member No: 256
  • 70 Thanks
  • 583 posts

Posted December 13, 2010 - 09:48 AM

Luke,
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.

#17 olcowhand ONLINE  

olcowhand

    Red Tractor Nut & Diesel Addict

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Sponsor
  • Contributor
  • Member No: 20
  • 35,605 Thanks
  • 29,834 posts
  • Location: South Central Kentucky

Posted December 13, 2010 - 10:00 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"!

#18 TUDOR OFFLINE  

TUDOR

    Tractorholic

  • Senior Member
  • Member No: 915
  • 543 Thanks
  • 497 posts
  • Location: Sault Ste Marie, Ontario

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.

Bob

#19 Luke OFFLINE  

Luke

    Tractorholic

  • Senior Member
  • Member No: 204
  • 134 Thanks
  • 352 posts
  • Location: Central Illinois

Posted December 14, 2010 - 10:00 PM

Great to know guys and thanks hydriv for that school lesson! LOL! I don't believe I'm gonna jack with the setting as I have not found a lawn overseeder for a category 0 three point hitch nor have I found one that weighs in under 900lbs so I think all this is in material! I however would like to install a pressure gauge just to see what its putting out for psi for grins and giggles.......does anyone know where to install the pressure tap for hooking a gauge on? Hydriv seems to know alot about hydraulics on these tractors......I need another lesson man! Thanks Luke

#20 TUDOR OFFLINE  

TUDOR

    Tractorholic

  • Senior Member
  • Member No: 915
  • 543 Thanks
  • 497 posts
  • Location: Sault Ste Marie, Ontario

Posted December 15, 2010 - 02:35 AM

Change the fitting for the hydraulic supply line at the hydro (left side for a Sundstrand) for a 'T' instead of a '90*'. Reinstall the supply line and install the pressure guage in the leftover open port of the 'T'. Start her up and dead end one of the cylinders. That will give you your maximum system pressure. Engine rpm has very little to do with max pressure, so you can do this at idle if you want. A spike in the pressure doesn't count, you are looking for consistent pressure.

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.).

Bob

Edited by TUDOR, December 15, 2010 - 02:44 AM.


#21 Luke OFFLINE  

Luke

    Tractorholic

  • Senior Member
  • Member No: 204
  • 134 Thanks
  • 352 posts
  • Location: Central Illinois

Posted December 15, 2010 - 07:19 PM

Thank you Bob! Thats very helpful information........appreciate you sharing your knowledge! Luke




Top