1050 woods backhoe hydraulic problems

[AKKAMAAN]

AKKAMAAN, could you pinpoint where exactly load check valves are located on parts diagram. could they be located under the shock/dampening valve? thank you for your help, i've learned more from you this evening than in all my other attempts
buckeye bob

I cant see around the entire valve and I am not familiar with this valve....as I said earlier....load check can be located either between the work ports, but that don't seem to be the case on this valve. 2nd option is under the shock valve, but your control valve do not seem to have shock valves on every work port. And there is no plug for the shock valve port either...so last option is on the back side of valve housing....

Look for HEX or ALLEN plug on the back side of housing.....

 

[robertpberg]

AKKAMAAN, i am going to the load checks first. also, in your opinion, could it be a faulty spool valve? thanks, buckeye bob

 

[AKKAMAAN]

could it be a faulty spool valve?

I wouldn't bet a dime on a faulty spool valve, before I have checked the load check.....

The load checks are there for just this reason....to prevent load from dropping when hitting the valve lever....Load checks are specially important for this reason on Open Center systems, because the oil pressure is low in the center core when valves are in neutral, on the pressure in the work port can be high. At beginning of spool travel, both pump flow and work port will be connected to tank via partly open center core. If load check is not working the load (boom) will drift down until pressure have been built up.

To build pressure, spool valve need to restrict the center flow.

How much spool needs to travel (lever stroke) to build necessary pressure, depends on flow (GPM) in the center core and the size of pressure there is to over come in the work port...

If work port have low pressure (light load), spool do not need to travel far to build enough pressure....

If flow is higher (by raised rpm's), spool wont need to travel far to build enough pressure....(pressure can be increased by raising rpm's)

If work port pressure is very high (very heavy load), spool need to be close at end stroke to build enough pressure, or at the point where the center core is fully closed. This is usually a condition to create max pressure from pump. (Max pressure=relief valve open, relief valve open=work cylinder stalls)

 

[pclausen]

I have a 1050 backhoe as well with the exact same issue. That is, when I pull the boom joystick towards me just a little, the boom drops, pull it a little further and it starts to raise. That starts after a few minutes of operation from a cold start.

Looking at the parts diagram below, I'm not sure which are the load check valves.

Is it item 3? (check valve)

Thanks!

 

[J_J]

Yes, #3 is the load checks.

Load checks are supposed to stop the cyl from moving when the spools are shifted.

 

[pclausen]

Thanks. That's a relatively inexpensive part. I'll get one on order with my dealer and report my findings after replacing my current one.

 

[J_J]

If one of the checks is good, use that to check the other circuit.

It might not be the check valves. Could be air in the lines/cyl.

Just remove, inspect, and clean before doing anything else.

 

[pclausen]

I got the check valve, but after popping the 'valve cover' I don't readily see where this guy would go.

Does it go inside the spool control valve?

Here are some shots of the valve assembly. The valve on the far right with the purple on the upper hose is the boom SCV. The only thing that appears to have a very small leak is the shock/dampening valve on SCV that controls the boom left/right movement. The 5 2400 psi relief assemblies also have a small amount of oil on them.

 

[J_J]

I believe the load checks are on the back side of the valve. You will have to pull the valve bank off or see if there is an access door about where your feet would go.

 

[pclausen]

Thanks JJ. I'll go ahead and pull the valve bank and have a look on the back side.