Tractor pump is too big for backhoe valveset, how to fix?

[aczlan]

Do you have a make/model on the backhoe and/or valve to know how many GPM they should be getting?

Aaron Z

 

[hirsch56]

Do you have a make/model on the backhoe and/or valve to know how many GPM they should be getting?

The backhoe is an Amerequip 85. I don't see any markings at all on the valves, except IN/OUT.

 

[J_J]

The problem happens at all rpms, even at idle.

Explain the dust caps and seals and show picture if possible.

Are you talking about the seals on the spools, and the cans on the bottom of the valve.

If you had a good valve and very little back pressure, you should have no leakage.

If someone hooked the valves up wrong, and high pressure was directed back up stream, that itself will blow the seals.

 

[aczlan]

The backhoe is an Amerequip 85. I don't see any markings at all on the valves, except IN/OUT.

Per the manuals on the Ameriquip site, their 80 series backhoes all take 4-5 GPM to run.

Aaron Z

 

[J_J]

Somewhere, the manufacturer states that if the BH is used on a tractor with a larger pump, to reduce the engine rpm to obtain satisfactory performance.

You don't need to bypass anything.

What is the size of the OUT hose on the BH valve?

You still have not told us the back pressure.

Where is the BH in the series hyd path.

Are you using the PB on the BH valve.

The hyd sizing nomogram, indicated the hose size should be above 1/2, and 5/8 in hose for 10 GPM, at a 15 ft/sec flow velocity.

If you used 5 GPM, you could use 3/8 as the OUT/return hose.

Excerpt:

While looking at the Prince web site, I came across this question and answer.

Q: I just put a Prince control valve on and it’s leaking out the back of the valve. What went wrong?
A: There is a very good chance that the outlet line (return to tank line) has been pressurized. Just one tank line spike, over 300 psi, can cause the valve to leak at either the handle or the spool end cap.

 

[hirsch56]

Aaron, thank you for the Amerequip link and manual. I had searched for that previously without success.

I don't have a way to measure the backpressure, but it is obviously too much. No other leaks. The flow is in the correct direction and the BH works well except for the constant leakage out of the dustcaps, but right now it is not mounted. The caps bulge up, and I have in the past flipped them over to get it to stop, but it doesn't last long before they bulge and leak again. I'll have to check the return line size, but I'm pretty sure it is 1/2".

I agree reducing rpm should help but it does not, so I think the problem is that I need to use PB in some way. I just now went and did some reading about PB. Am I correct that using PB allows to connect them in parallel instead of series?? I connected the BH in series with the loader when it was mounted, and I am not using the Power Beyond in the loader valve. I don't know if the PB sleeve is in the BH or not, but I suspect it is not. I don't think I need PB because I never use the loader, 3PH, or BH at the same time.

 

[aczlan]

If you can put another tee before the ball valve, you could add a gauge there if you wanted to see the pressure. $16 (plus shipping) will get you a 3000PSI or a 5000PSI gauge.
I cant speak to what is needed with respect to power beyond.

Aaron Z

 

[J_J]

If your valve has PB, you should install a PB sleeve or hex plug and connect the valve in series only, no parrallel anything.

If you did not use the PB outlet when connecting the BH in series, what I said above is true.

What would happen is when you used the 3pt, and maxed it out, causing the relief valve to operate, it does this at tractor max operating pressure. This pressure is felt from the 3pt, back up through the BH valve, loader valve, to the pump.

Most OUT/return ports are limited to about 500 psi.

Read the excerpt from Prince again.

If you want to get rid of most of the back pressure, run the OUT port hose from BH valve directly to tank. The 3pt will not be usable until you put the 3pt back in series with the hyd flow.

Whatever back pressure you have will be working against the fluid flow.

Who set up the BH for you?

Can you show a picture of the BH valve on the OUT port side.

Installing the PB might not help stop the leakage, but PB is the way to connect valves in series.

These are two kinds of PB adapters.

 

[aczlan]

An alternative to PB might be to use your rear remote locked into position to run the backhoe (assuming you have one). Then you wouldn't need power beyond.

Aaron Z

 

[J_J]

I do not understand the reluctance to connect things correctly.

But whatever.