loader won't lift with different cylinders

[vermonter85]

Hi, First my tractor is an A/C 5050 with an allied loader, I am having troubles with my loader after I replaced the lift cylinders with a pair of larger ones off another loader. The "new" cylinders are 3" diameter and the originals are 2" diameter they both are the same length. I can lift the bucket empty by running the tractor wide open and it will hold it up once there but it won't lift anything. As a side note the bucket dumps and returns normal. My big question is do the larger cylinders require a bigger pump with more pressure and/or volume. Any help would be great, thanks, Mike

 

[J_J]

Once the cyl are full of fluid, the pump is pumping the same volume, but it will take more time to extend or retract. You will have more force with the larger cyl.

You need a hyd gage in the circuit to tell if you have any pressure. You can test any pressure the valves sees by putting the gage in a tee at the IN port. You could remove a cyl hose and check pressure and flow.

Do you have the same hose feeding the base end of both cyl. Did you perhaps cross connect the hoses at the cyl.

Are there any QD's in the cyl hose , if so, double check them for flow through the QD's. If the rods are extending, then you have flow.

Check the spool to see if it is actually moving in or out of the valve.

If you just installed the valve, or worked on the valve,you might have over tighten the bolts and caused the spools to bind.

You could switch hoses with the curl circuit and see if there is any change.

http://www.federalfp.com/pdf/Prince Valves Manual Loader.pdf

Look at the last page.

 

[Stonehaller]

Welcome to TBN.

First a couple of questions. Was the loader working ok with the previous 2 inch cylinders? Did you have change any other valves or hoses?

If nothing else was changed, it sounds like the piston seals are leaking badly on the 'new' cylinders.

You should not have to change the pump for the cylinders to work. The larger diameter cylinders will move noticeable slower than the original cylinders and will produce significantly more force. Be careful that you do not overload the loader arms or mounting frame. If you want the cylinders to move faster, you would need a pump with higher volume.

 

[vermonter85]

J.J. I did switch with the curl circiut and had the same results, and everything was working before, until I popped one of the seal retainers out of the end of the cylinder (mutiple times during the last big snow storm) it bulged the end of the cylinder slightly promting the replacement of both cylinders with the different style of retainers side note the cylinders were the only thing changed

 

[J_J]

Remove the hose going to the tee to the two cyl and place in a bucket and see if you have flow.

 

[vermonter85]

Hey guys, I got a chance to check things out and I put the old cylinders back on to see what would happen and everything seems to work as it should, so it appears that the "new" cylinders will be getting a rebuild and then another try. Thanks for your inputs. Mike

 

[J_J]

Are you saying that you put fluid to each of the cyl, and they did not move? Even if the seals are bad, it should still push the rod out to the end, unless the nut off the back of the piston.

 

[Kernopelli]

As was pointed out, by increasing the size of the cylinders you are both dramatically increasing your lifting capacity/forces but also slowing your loader down. If you are running the loader off the tractors hydraulics you have about 6.5 GPM of flow. For example if the cylinders have 24" of stroke with a 2" bore and 1.125 " rod your cycle times (full extend/retract) are about 5.1 seconds. With all things being the same except the cylinders being a 3" bore, you've increased your cycle time to 12.8 seconds.

If you are running the loader off a high flow PTO pump etc, you probably won't feel like you're watching paint dry when compared to the old 2" cylinders but be aware that pretty much regardless of pump flow you are going see it take about 2 1/2 times as long for the loader to cycle.

 

[J_J]

He never did say if the rods moved in or out.

 

[Kernopelli]

He never did say if the rods moved in or out.

In his first post, concerning the 3" cylinders he said "I can lift the bucket empty by running the tractor wide open and it will hold it up once there but it won't lift anything. I take that to mean the cylinders would just barely lift the loader itself but not any kind of load.