What causes this?

[AKKAMAAN]

This is a common design error...what happens is that gravity from the bucket pushes oil out of one side of the cylinder piston, faster than the pump can replace the void on the opposite side of piston.....
depending on how cylinder is hooked up, extending or retracting, wqhen this happens....problem can be solved in differnt ways.....
a regenerative valve is best cure if cylinder is extending....but do not work on retract...
one way adjustable orifice/ check valves (on meter out)is another option, that will slow drainage so pump can keep up with the void....


Question: IS CYLINDER EXTENDING OR RETRACTING WHEN THIS BUCKET DROPS DOWN??

 

[SPYDERLK]

Oh. Just voids in the cyls. Didnt realize he was describing that phenomenon.
larry

 

[dcyrilc]

This is a common design error...what happens is that gravity from the bucket pushes oil out of one side of the cylinder piston, faster than the pump can replace the void on the opposite side of piston.....
depending on how cylinder is hooked up, extending or retracting, wqhen this happens....problem can be solved in differnt ways.....
a regenerative valve is best cure if cylinder is extending....but do not work on retract...
one way adjustable orifice/ check valves (on meter out)is another option, that will slow drainage so pump can keep up with the void....


Question: IS CYLINDER EXTENDING OR RETRACTING WHEN THIS BUCKET DROPS DOWN??

Extending for mine. Not sure about the OP. Mine will also do it with an empty bucket.

 

[AKKAMAAN]

Extending for mine. Not sure about the OP. Mine will also do it with an empty bucket.

Extending means you could utilze a SUN Hydraulics regenerative valve between control valve and cylinder...around 100-150$...
another option is to use a one way adjustable restrictor/flow control valve, on the rod side line..... around 30$

Read this pdf from SUN about regen valve tips....
To design a regen valve installation you need to know pump flow at idling rpm's, cylinder bore diameter, piston rod diameter, and pressure settings/requirements to operate the bucket cylinder....

The difference between these two first options, is that the regen valve will let bucket dump at "full speed", while the restrictor will slow down the dump (the extension).....some times you want the dump go fast huh??!!

The third option is to throttle "hard" while dumping bucket....that way the pump will put out more flow to fill the void on the capped side....:laughing:

 

[handirifle]

What it is, is when I go to dump the bucket, often times (not always), it will travel about 3/4 of the way, then stop. It seems them I need to rev the engine a bit with the valves in neutral, then full left again, and the bucket completes the last bit of travel. Not sure what the term is for it, but the back of the bucket is rotating closer to me as I sit in the seat.

When in complete motion, the bottom of the bucket is near verticle. Otherwise it stops about 15-20deg short of that.

 

[AKKAMAAN]

What it is, is when I go to dump the bucket, often times (not always), it will travel about 3/4 of the way, then stop. It seems them I need to rev the engine a bit with the valves in neutral, then full left again, and the bucket completes the last bit of travel. Not sure what the term is for it, but the back of the bucket is rotating closer to me as I sit in the seat.

When in complete motion, the bottom of the bucket is near verticle. Otherwise it stops about 15-20deg short of that.

What make and model # is your loader??

This is one of the issues, where a little video clip that shows how your problem acts, could help to explain. Preferably from the side of the loader showing all the pivot points for bucket and cylinder....

Could you make a video clip and post it please??

Or find a video clip online that shows your FEL equipment doing this....