Garden Tractor Forums banner
1 - 20 of 21 Posts

·
Tractorholic
Joined
·
399 Posts
Discussion Starter · #1 ·
Looking at purchasing a 58" overseeder and want to pull it with my 1655 but worried about it picking it up with full of grass seed! I'm not worried about keeping the front end down......have a bunch of john deere lawn and garden suitcase weights for the front. thanks Luke
 

·
Red Tractor Nut & Diesel Addict
Joined
·
32,409 Posts
I think 400lbs would be safe enough with front weighted to keep the front down. My 1855 lifts my tiller like it's not there and it likely tops 200+lbs or more. Of course the closer the main weight of the implement is to the hitch, the easier the lift.
 

·
Tractorholic
Joined
·
399 Posts
Discussion Starter · #3 ·
Thats kinda what i was thinking.....400 to 500lbs max. Where does the 3 point get its oil from to raise and lower? Its not like a farm tractor with external lift cylinders........does the hydrostatic pump supply the ground drive plus 3 point lift system? If so can a fella turn the pressure up to gain more flow/pressure to lift more weight.....like a farm tractor? If yeah then has anybody done this and how do you do it? Thanks Luke
 

·
Red Tractor Nut & Diesel Addict
Joined
·
32,409 Posts
Yes, the charge pump that supplies the hydro it's oil also does the hydraulic lift functions. They are set to between 700 to 800psi, but that will lift a lot, so doesn't mean it's been tampered with, plus you don't want to bother anything in the system if everything is working properly. They are a simple valve which is adjusted by adding/taking away shims under a spring which seats the regulator plunger.
 

·
Tractorholic
Joined
·
399 Posts
Discussion Starter · #5 ·
Hmmm, thats alot of psi already without monkeying without setting it higher.......I've set pressures up on our MF1155 and MF2775 farm tractors before but we're talking alot bigger systems with more capacity and bigger lines! This is just all out of "if need be" but whats the highest you could set pressure at without having problems.......don't need anymore of those if you know what i mean!! LOL! Luke
 

·
Red Tractor Nut & Diesel Addict
Joined
·
32,409 Posts
I'm not sure what pressures it would be cpable of, but it's the small pin that drives the gy-rotor in the pump that I would be concerned about shearing....that or reaming out the gy-rotor itself. I bought a JD F935 that wouldn't pull. Turns out someone had monkeyed with the pressure regulator & it ruined the charge pump rotor. New one was $275.00!! I bought a complete used hydro pump for $50 delivered instead.
 

·
Tractorholic
Joined
·
399 Posts
Discussion Starter · #7 ·
Yeah thats the problem screwing with stuff and trying to get the max out of it! Opens up another can of worms! My luck I'd shear the key in the pump and the pieces would tear the pump up! Maybe I'll do some testing with tractor weights to see what it'll do! Will let ya know what i find out! Thanks for your time Dan! Merry Christmas! Luke
 

·
Premium Member
Joined
·
1,616 Posts
olcowhand said:
I'm not sure what pressures it would be cpable of, but it's the small pin that drives the gy-rotor in the pump that I would be concerned about shearing....that or reaming out the gy-rotor itself. I bought a JD F935 that wouldn't pull. Turns out someone had monkeyed with the pressure regulator & it ruined the charge pump rotor. New one was $275.00!! I bought a complete used hydro pump for $50 delivered instead.
when I first put the loader onto my 1655 I couldn't get it to work properly from just using the charge pump. There's a little story to this so bear with me.At the time the hydrostatic was giving me problems as well so I had taken it in to a guy I know who repairs them.He Had to replace some parts in the unit to get it to work .I mentioned to him about it not working good for the loader and he said he'd fix that for me.Well as it turns out he increased the pressure by making a different shim for the spring.He ended up having to rebuild the charge pump again as when the pin broke it scored the pump.So the story here is that the setting is only supposed to be 750 psi to be safe and not shear that pin,which will score the pump.I ended up putting on a extra pump that's driven off the motor and this works perfect.Larry
 

·
Senior Member
Joined
·
4,482 Posts
massey driver said:
when I first put the loader onto my 1655 I couldn't get it to work properly from just using the charge pump. There's a little story to this so bear with me.At the time the hydrostatic was giving me problems as well so I had taken it in to a guy I know who repairs them.He Had to replace some parts in the unit to get it to work .I mentioned to him about it not working good for the loader and he said he'd fix that for me.Well as it turns out he increased the pressure by making a different shim for the spring.He ended up having to rebuild the charge pump again as when the pin broke it scored the pump.So the story here is that the setting is only supposed to be 750 psi to be safe and not shear that pin,which will score the pump.I ended up putting on a extra pump that's driven off the motor and this works perfect.Larry
10-4 on that one Did the same thin myself a long time back. 750 PSI NO MORE ont he charge pump.
 

·
Tractorholic
Joined
·
399 Posts
Discussion Starter · #10 ·
Thats good to know! Note to self....."keep hands off the charge pump setting" Thanks Larry, I'm gonna see just how much weight she'll lift useing front tractor suitcase weights.......u ever pushed the envelope and checked the lift capacity on your 3 point? Thanks Luke
 

·
Tractorholic
Joined
·
583 Posts
My advice would be to leave the relief setting on the hydro pump alone. I'd just put the seeder onto the three-point and then lay the bags of seed on top to see if it will lift the implement when it's full. The leverage of the implement is going to affect what the 3 point will lift. The closer in to the center line of the lift arm holes, the easier it is for the 3 pt to lift the weight.

Now let's say for a second that your hitch won't lift this unit and this is an ongoing need to use this device. One solution is to remove the cylinder from the hitch and replace it with another one that has the same stroke and rod diameter but is larger in diameter. If your cylinder is 2 inch right now and you go to a 2 1/2" or 3" diameter cylinder, you will vastly increase the amount of weight that hitch will lift. There is math available to calculate the difference between the stock cylinder and the larger replacement. Of course, a new bottom mount for the cylinder would have to be fabricated and welded to the bottom of the hitch plate but that's a minor issue. The hitch will rise up a bit slower and fall a bit slower but not by a lot. You don't want to go crazy here but I bet a half inch larger will make the difference.
 

·
Tractorholic
Joined
·
507 Posts
According to Sundstrand in their Bulletin 9679, Revision C, June 1978.

"Implement Flow & Press: 1-3 gpm with relief pressures from 700 to 1000 psi (optional)"

The MF4850 tiller is supposed to weigh 320 lb., without the extra dirt stuck to it.

An increase in cylinder diameter from 2" to 2.25" will yield a 25% increase in lift capability with a corresponding increase in time to lift/lower.

I'd be more concerned about the pin and bracket holding the cylinder on the tractor. Mine was bent from stock pressure and cylinder size when I got it 28 years ago, although that could be from pulling something with a 3PH implement.

Bob
 

·
Tractorholic
Joined
·
507 Posts
I would make a guess that it's just a shim or a heavier spring in the relief valve to bump the relief pressure up. The pump itself doesn't care. The housing is cast iron and 1000 psi is not a lot of pressure compared to what the main pump can withstand. The casting for the charge pump would be the limiting factor and I don't think I'd trust it too much beyond 1000 psi. unless I had a spare close at hand.

I'm just reading and quoting from Sundstrand's literature. I never tried it but these are strong, tough units.

A bigger concern is the effect on the tractor hydraulic support structure. It's not all that strong to deal with a 33% increase in force!

Bob
 

·
Tractorholic
Joined
·
583 Posts
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.
 

·
Red Tractor Nut & Diesel Addict
Joined
·
32,409 Posts
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"!
 

·
Tractorholic
Joined
·
507 Posts
olcowhand said:
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
 

·
Tractorholic
Joined
·
399 Posts
Discussion Starter · #19 ·
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
 

·
Tractorholic
Joined
·
507 Posts
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
 
1 - 20 of 21 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top