sagging curl on front end loader

[TTTTTT]

Heres a recent thread that may help as well

http://www.tractorbynet.com/forums/hydraulics/207979-help-curl-cylinders-acting-up.html

Dave

 

[merrickvilleguy]

Spoke with the dealer this morning, and he suggested yanking the cylinders off and replacing em (I'm 2 weeks outside warranty and they are still going to eat it) ... so will see if that covers things ... or if its the valves that are shot ?

 

[AKKAMAAN]

Spoke with the dealer this morning, and he suggested yanking the cylinders off and replacing em (I'm 2 weeks outside warranty and they are still going to eat it) ... so will see if that covers things ... or if its the valves that are shot ?

(2 mins itll sag about 1/4")

1/4" drift on cylinder or 1/4" drift on the front end edge of the bucket??

If we assume bore 2" and rod 1", a 1/4" drift on cylinder (cyl extends on drift, flow from rod end) is about 0.59cui or 12.9cc. That will make a 6.5 cc drift per minut, which is a little more than normal for a spool valve leakage, especially if drift is under low pressure.

Spool valves always leak, and they are designed to do that. A "normal" spool leakage number is around 3 cc/min @ 1500 psi. Spools normally do not wear like a piston seal, and leakage can be expected to stay almost the same over almost the entire lifetime of the equipment unit.

The drift can also be caused by a leak between cylinder and spool valve, if there is a work port PRV installed.

How many total hours of operation do you have on your FEL??

I still think there is a good chance, that replacing the cyl's will fix the problem. Please keep us updated.

 

[merrickvilleguy]

the 1/4" drop was for the level gauge, I later did a 10 minute measure of the cylinder of 1.75" at 1500rpm and no load (this amounted to a lot at the edge of the bucket)

edit: just under 200 hrs on the tractor (1yr old) and most of that the loader was on, probably 1/4 of the hrs are loader work

 

[J_J]

You seem to only be talking about when the engine is running.

What is the rate of fall with the tractor not running. The valve could be leaking fluid into the base end.

Raise the lift arms up fully, and curl back the bucket and shut off engine, then tell us what the leak down is.

 

[AKKAMAAN]

First of all, the engine rpm's should not have any noticeable impact on the cylinder drift. There is of course a few psi variation of back pressure in the return line, at different rpm's.

Lifting the FEL all the way up, and the curl all the way up/back, will certainly change the leverage structure on the curl cylinders and the bucket point of gravity relative to the bucket pivot point. In a fully raised position like that we can assume a less pressure in the curl cylinder and therefore less drift.

This FEL lift/bucket curl drift is for sure a PITA and a hazard when travelling on the road, especially with a heavy load in the bucket, or on the forks if such are used.

 

[J_J]

Are you sure that the spools can't leak and add some fluid to the base end of the cyl and aid to curling the bucket down?

If a valve lever does not reset to neutral, what would happen?

 

[J_J]

If you want positive confirmation that the seals are leaking, add some shut off valves to the curl cyl, grab a load and lift somewhat, and then shut off both valves. If the bucket curls down, you will have your answer.

 

[LD1]

Just swap out the lift and curl hoses at the valve.

Keep in mind that the functions will be backwards.

If the problem moves to the lift, it is the valve.

If the problem stays the same, it is the cylinders.

 

[merrickvilleguy]

Just swap out the lift and curl hoses at the valve.

Keep in mind that the functions will be backwards.

If the problem moves to the lift, it is the valve.

If the problem stays the same, it is the cylinders.

actually thought of this at work today and tried it out at home ... sure enough the curl still sagged ... so now I have to take the curl cylinders off and get the seals fixed