Picking Backhoe Hydraulic Lines

[welderboy14]

Hi,

i am currently building a towable backhoe, i am finly at the stage were i have bought the Hydrulic pump and was wondering if anyone knows what size hose i sould use?

Pump: 6GPM
Cylinders: 2"
Engine: 13HP
Valve: 2 hydrulic joy sticks

Thanks

 

[Gale Hawkins]

Reid some of the engineers have have a technical view. I just know our 60 HP Loader/BH uses 1/2 inch but the outriggers use 3/8" for some reason.

TSC in their store locally stock 1/4, 3/8, 1/2 and 3/4 pre made hoses. The 1/2" we put on last Saturday was actually rated at 4000 where most are 3500 it seems.

You may want to look at some log spliters with about the same specs as your hoe "assuming" they put some planning into their design.

It sounds like a great and useful project that you have underway.

 

[kennyd]

My suggestion is 1/4" hose from the valve to the cylinders, 3/8" hose from the pump to the valve, and finally 1/2" hose for the return line. You don't need more than that with a 6 GPM pump.

 

[oldnslo]

Hi,

i am currently building a towable backhoe, i am finly at the stage were i have bought the Hydrulic pump and was wondering if anyone knows what size hose i sould use?

Pump: 6GPM
Cylinders: 2"
Engine: 13HP
Valve: 2 hydrulic joy sticks

Thanks

What size ports on in the pump and cylinders and valve?

For your main cylinders I would use 3/8" hose to help keep the fluid velocity lower and descrease pressure loss which equates to less work you can do.

Pump inlet line should be a minimum of 3/4" inch and if going to be used in coldweather consider going to 7/8" or 1".

Pressure line from pump to control valve I would make 1/2" and the return line from the valve 5/8".

This a based on running 6 GPM and figuring cylinder size ratio of 1.3:1 which will give a return flow of 7.8 GPM when retracting the cylinders.

Ag equipment and infrequent use items will typically have hydraulic lines under sized (excessive flow velocity) for the rated flow they are passing. If this is something you are going to be using very infrequently you could go smaller on all of the lines EXCEPT the pump inlet. Make this to small and you will ruin your pump.

Roy

 

[welderboy14]

ok thanks for the help, i think i will go with the 3/8 hose.

one more qustion whats the best way to measure what length hosei need, i was thinking of using some 1/2" rope.

 

[Gale Hawkins]

And add 5% because under high pressure they shorten.

 

[welderboy14]

And add 5% because under high pressure they shorten.

really they shorten never knew that thanks

 

[Gale Hawkins]

really they shorten never knew that thanks

2-3% actually but the article stated to go 5% over. If they swell just a little then it shorten them by a tad.

Like with log chains an inch too much is better than a inch short.

 

[wdchyd]

Remember the old chinese finger torture when we were kids...you could not get your fingers loose until you push in to expand it....thats how hydraulic hoses shrink while under pressure , the wire braid is similar in construction....when they expand they shrink