Ameriquip 80a backhoe hydraulics ratings

[Stimw]

yes. The point is; if the valve can only handle 8 gpm, putting 10 gpm through it could cause problems whether not it is going to one of the cylinders.
You would have to make sure you never see more than 80% of rated engine rpm while driving.

As long as your pressure relief valve is working properly there is nothing to worry about.
Hydraulic items have a safe working limit above working pressure.
Think of a garden hose with a nozzle on it.
When you restrict the flow to a small stream or stop the nozzle doesn't explode as long as the water pressure is in the acceptable range.

 

[Groo]

And when you push more fluid through than the relief can handle?

 

[Stimw]

The relief valve is sized for the pump output.

 

[Grandad4]

but as you drive around with the loader, the valve for the hoe will see full rated flow, since that much oil is going through the whole system whenever you hit peak rpms, weather or not you are using the hoe at the time, it still sees it.

The issue is not 8 gpm flow, it's the psi of the tractor vs the bursting strength (in psi), of the backhoe components. Usually there is considerable safety margin built into OEM hydraulic components but if there have been repairs, you want to be sure the correct parts were used. Having a surplus of hydraulic flow is a good thing and nothing to worry about.

 

[aczlan]

The issue is not 8 gpm flow, it's the psi of the tractor vs the bursting strength (in psi), of the backhoe components. Usually there is considerable safety margin built into OEM hydraulic components but if there have been repairs, you want to be sure the correct parts were used. Having a surplus of hydraulic flow is a good thing and nothing to worry about.

Not exactly, running 10GPM through a 8GPM valve will create a lot of heat. Not a big deal for 5-10 minutes at a time, but an issue for longer.
If your pressure ratings match and you want to make sure the flow wont be a problem there are three options:
1. Priority flow divider such as: 8/3 GPM Prince Priority Flow Divider w/Relief | Prince Mfg | Brands | www.surpluscenter.com - That will feed the first 8GPM to the backhoe and dump the rest in the "tank" link going back to the tractor (bypassing the 8GPM valve)
2. A selector valve (to let you choose to bypass the backhoe valve or not): 3/8" NPT 2 GPM Prince Selector Valve | Prince Mfg | Brands | www.surpluscenter.com
3. Run the backhoe off of one of the tractor's rear remotes and only turn the remote on when you are ready to use the backhoe

Aaron Z