New Thumb Build

[lcgoatboy]

I have my own theory,the 2 relief valves are not exactly the same pressure 1700 ish and 1800ish. I want to balance the 2 with the machine running and watching the reaction of the thumb. I think???

 

[ptsg]

I dont think that the thumb has enough weight to open the relief valve

 

[firemanmike69]

I have my own theory,the 2 relief valves are not exactly the same pressure 1700 ish and 1800ish. I want to balance the 2 with the machine running and watching the reaction of the thumb. I think???

I'd try the machine running while I slowly raised the setting on the relief and see if it stops. Then check the pressure

 

[firemanmike69]

Looked in the service manual today here's the layout of the valve and the functions




And if you're not reading the pressure directly at the attachment here's where you can read them on the pump

 

[CNC Dan]

So I do have relief valves on the excavator,that's good. The pressure was 3000psi we lowered it to 1800,that's good! The bad is the thumb ram creeps down quite fast,15 seconds or so. What did I do wrong?

Did it start when you adjusted the relief valves. If not, it sounds like your valve for the thumb has a 'motor spool' in it, rather than the usual type of spool.

 

[lcgoatboy]

I had no time today. I hope tomorrow.
The Takeuchi said they adjust their thumbs to 1800 psi,it seems a bit low to me??
Also the thumb only started this creeping after I adjusted the relief valves.

 

[lcgoatboy]

Looked in the service manual today here's the layout of the valve and the functions


View attachment 410954

And if you're not reading the pressure directly at the attachment here's where you can read them on the pump


View attachment 410955

Thank you Mike. I'll be on this tomorrow.

 

[firemanmike69]

Thank you Mike. I'll be on this tomorrow.

No problem sorry it took me so long to get back to you

 

[lcgoatboy]

No problem sorry it took me so long to get back to you

Ok,so today I adjusted one of the relief valves until the ram stopped lowering. That worked but there is not much clamping pressure. I was told 1800 psi was the number to set the thumb at. Is this at an idle? Thanks.

 

[David Devuono]

I would like to see a picture of the relief valve. I am pretty sure mine has a cross over relief valve near the base of the main boom. Its quite a large unit but I have purchased cross over relief valves from Princess auto for other projects and they where not $250. PA has a 10GPM Poppet style for 99 bucks.