Excavator boom swings and drops too fast

[r8f1k]

I have an old Case DH4B trencher/excavator combo. Finally got the excavator up and running with the controls in the two joystick SAE configuration. When I run it, the boom drops FAST. Barely move the stick and she slams down. The left and right control is not quite as bad, but it is too fast. When I swapped out the old 6 stick valve for the twin joysticks, I could see screw in orifices in a few of the ports. They had pretty small holes and they were threaded in somehow. I couldn't get them out with a big flathead, they had a slot in them. Is there anything like that I can add to the current control valve to slow the cylinders down like the orifices? They looked just like sprayer orifices.

 

[oldnslo]

Adding thread in inserts Depends on how deep the ports on your valve are threaded. You can also purchase orifice fittings and or fittings threaded to accept an orifice. Another option is in line flow control that is adjustable. These are also called needle valves. Just make sure they are pressure rated for hydraulic service.

 

[r8f1k]

Is there anything that can be placed right on the end of a JIC fitting? There isn't too much room near the control valve. If so, how do you decide what size to put in?

 

[r8f1k]

Will this work?

 

[Rich B1]

Likely the orifices you saw were orifice checks that were port options in the valve. The checks allowed free flow in one direction, restricted flow in the other.

Most circuits using orifices are typically installed to allow exhaust metering, especially on circuits that gravity can affect, like your boom down. By restricting the exhaust, there is back pressure in the cylinder to prevent it from running ahead of pump flow.

Parker did make a fitting that had an orifice check that was part of the fitting. It was available as a check and a number of sizes. I don’t know if those are available in the consumer market. Maybe contact a Parker parts store.

The adjustable flow restrictor is a good option, you can have free flow one direction, restricted flow the other. They don’t have to be at the valve, you can install them at the cylinder ports or in-line if needed.

 

[oldnslo]

Will this work?
View attachment 791399

If that is the correct size fitting it looks like it should.

 

[Unicam]

restricted orifice fitting. it will slow both ways obviously but less chance for damage. also, you can drill it out slightly if it's too slow. from my experiance adjustable flow valvces are garbage, don't hold setting, leak and prone to failing plus cost to much

https://www.tractorsupply.com/tsc/p...U4qNtb-PIgdS1vJwH07SmyUnp5wSYO_xoCz-IQAvD_BwE

 

[LD1]

What is the GPM of the machine and what was the GPM rating of the valve?

Sounds like the valve was too big. It comes up often on here but you want to try and match the rating of th valve as close as you can with the flow of the machine. If you have a machine that runs at 8gpm and put a 25gpm valve on it you loose the ability to feather the controls.

Its like trying to control a garden hose sized stream of water with a fire hose nozzle. Barley crack the nozzle and you are already at full garden hose flow....

 

[5030]

Because I'm inherently cheap, I make my own restrictors out of appropriate sized copper blanks and drill my own restrictor holes in them the copper acts as a seal too. You can use brass as well but copper is better.

 

[LD1]

Do them copper blanks cost you about $0.01 ea?