Need help

[gilbertson]

I screwed somrthing up.... My mini backhoe started leaking betweeen the 6 gang valve body. i tighten the bolts up but now it heats up and slows down. I am thinking the relief valve is not set right but do not know which way to turn it. When hot several functions work at the same time.

Vern

 

[clemster]

you may have torqued to bolts too much causing the valve spools to stick.

 

[gilbertson]

I thought the same and loosened them only to have them leak, tighten till they stopped. what is between the valve spools?

 

[AKKAMAAN]

I thought the same and loosened them only to have them leak, tighten till they stopped. what is between the valve spools?

Orings between the sections

 

[kennyd]

There are O-rings between the valve sections. You need a gauge to properly set the PRV (pressure relief valve)

 

[gilbertson]

Where shoule the gage be installed? supply line or return? Should the supply line go to the relief valve first on the 6 gang valve spool, which it is presently or should the return line?

thanks for your help

 

[AKKAMAAN]

TEE gauge on supply line, between pump and first control valve section.... check before buying gauge what pressure setting is recommended, (if 3000psi is recommended I'd use a 0-5000psi gauge, if 2500psi is recommended i'd use a 0-3000psi gauge etc)

 

[J_J]

I screwed somrthing up.... My mini backhoe started leaking betweeen the 6 gang valve body. i tighten the bolts up but now it heats up and slows down. I am thinking the relief valve is not set right but do not know which way to turn it. When hot several functions work at the same time.

Vern

If the valve was working before, and then started to run hot and leaking, then I would suggest separating the valves and replacing all the o-rings, and remove the relief valve out and clean it. If a piece of crud gets under the relief valve, the relief will not close, and let fluid bleed off at a constant rate, causing heat. Sometimes, the in-rush of fluid will knock out any crud stuck in there. But, anyway, the gage goes in a tee in the input side of the valve, and the input side usually has a P, or IN, letters stamped on the valve. The relief valve is often near the input.

I would also recommend getting o-rings from the manufacture, and not the hardware store.

As far as setting the relief valve, you would have to know the specs of the valve, and set it 50 to 100 psi below the max psi.

 

[gilbertson]

I picked up a gage today but got the wrong size fitting so will get the right ones tomorrow. The valve spool was very hard to move with the 2 middle valves the tightest of the six, as soon as I loosened up the all thread all valves moved freely. I took one apart so I could get replacement o rings. Why with cast iron body's do they torque with some pressure and what torque setting should I set them too when I get o-rings?

 

[kennyd]

I picked up a gage today but got the wrong size fitting so will get the right ones tomorrow. The valve spool was very hard to move with the 2 middle valves the tightest of the six, as soon as I loosened up the all thread all valves moved freely. I took one apart so I could get replacement o rings. Why with cast iron body's do they torque with some pressure and what torque setting should I set them too when I get o-rings?

Here are the Prince instructions for their SV series stack valves: http://www.princehyd.com/LinkClick.aspx?link=products/valves/SVInstS.pdf
That should help.

 

[AKKAMAAN]

I picked up a gage today but got the wrong size fitting so will get the right ones tomorrow. The valve spool was very hard to move with the 2 middle valves the tightest of the six, as soon as I loosened up the all thread all valves moved freely. I took one apart so I could get replacement o rings. Why with cast iron body's do they torque with some pressure and what torque setting should I set them too when I get o-rings?

you NEED manufacturers O-rings and manufacturers torque recommendation for that number of sections there is in YOUR specific valve

IMO those bolts should only be tightened so much so the o-rings get compressed. Which means the cast iron sides in the sections only get to "touch" each other....then there will be no material stress in the valve housing to cause the spools to stick....

 

[gilbertson]

Update:

I picked up new o-rings today from a hydraulic service company, took the valve assembly apart and intalled new o-rings, several of the existing had RTV around them. Installed a gage right off a Tee fitting on the supply line of the pump, 3000 psi, the relief vavle is stamped 2500.

Started engine and leaks every where, the pressure was at 2500 and not matter where if I screwed in or out the 2500 was constant. When under load the gage jumps to over 3000 psi, the cylinders seem to be working against them selves, not moving one way or the other. Blew 2 hoses at the same time.

I have a 5.5 briggs, northern hydraulic pump model S1012,

i think there is a problem in the 6 gang spool valve assembly and the relief valve. Thanks for everyones help

 

[J_J]

Did you take the relief out and clean it. Was there any pressure on the gage before you activated a lever?

Are you sure you have the hoses on right. A set of cyl hoses should go to the same valve section. You could have crossed them over, and that would lock up a cyl.

 

[gilbertson]

I took the relief valve out and cleaned it, had 2500 psi with out moving a lever. I will check the hoses again in the morning but am pretty sure they are on right.

 

[AKKAMAAN]

sounds like you have a closed center valve...

 

[J_J]

You are not supposed to have any pressure or very little because the circuit is an open center circuit. There is something blocking the fluid, a QD not seated, hose hooked up wrong, etc. What position is your 3pt lever. Move the lever about half way and try again, and report the pressure.

Where did you install the return hose?

Is that valve a PB valve?

 

[gilbertson]

here is the latest, when I bought the unit it has quick disconnects to seperate both supply and return for a log splitter, the valve for the splitter was blockin the retune . now I have 450 psi and have set the releif at 2300 psi. the spool block is leaking but everything is working. I am thinking the guy I bought the unit from had tougued the spool. Thanks for all your help