743b has no down pressure on boom control???

[billrbg]

Ok thanks for the replies guys... Sorry I haven't checked back earlier... I am definitely sure aux hydraulics are not stuck as I have a 4 in one bucket for one... And two, I have attached my backhoe and it works as it should perfectly... The only problem I have is tht the boom just will not come down under hydraulic pressure. It only comes down when I mash the pedal into detent... And now after using it for a few days like that it won't even stay in detent no more... Another symptom is if I mash the pedal into detent as soon as the bucket begins to lower if I rock the slightest bit back on the pedal it will have hydraulic power but uncontrollably.

I would tee-in temporary pressure gauges at the ports of one of those boom cylinders, to look for hints on what is going on. Also (a separate check), open one port on each cylinder and see how much fluid comes out when the other port is pressurized, try to get a feel for whether a cylinder piston seal is way bad. Point is, you are probably going to have to dig into the Control Valve, and that is the LAST thing you want to tackle; check everything else first... Maybe connect the lift/boom cylinders to the aux and see how lift operates? All of these games will require some expense for fittings and hoses, which you will probably find future or repeated use for, but that Control Valve is miserable!

 

[Onemancrew]

I would tee-in temporary pressure gauges at the ports of one of those boom cylinders, to look for hints on what is going on. Also (a separate check), open one port on each cylinder and see how much fluid comes out when the other port is pressurized, try to get a feel for whether a cylinder piston seal is way bad. Point is, you are probably going to have to dig into the Control Valve, and that is the LAST thing you want to tackle; check everything else first... Maybe connect the lift/boom cylinders to the aux and see how lift operates? All of these games will require some expense for fittings and hoses, which you will probably find future or repeated use for, but that Control Valve is miserable!

Ok... Well, I ended up pulling spool out.. It's a pretty piss easy job to be honest I'm not sure what I was worried about now.. And I believe I have solved the issue. One of the springs that holds the detent ball had broken into little bit and the little washer that the centreing spring sits on was shattered. See pic for reference. For anybody else having similar issues.

Thanks to this forum.. You guys are great.

 

[Onemancrew]

Ok... Well, I ended up pulling spool out.. It's a pretty piss easy job to be honest I'm not sure what I was worried about now.. And I believe I have solved the issue. One of the springs that holds the detent ball had broken into little bit and the little washer that the centreing spring sits on was shattered. See pic for reference. For anybody else having similar issues. Thanks to this forum.. You guys are great.

http://i67.tinypic.com/2ex26pw.jpg

 

[Onemancrew]

http://i67.tinypic.com/2ex26pw.jpg

Ahh damn it the pic wont embed...

 

[billrbg]

Ahh damn it the pic wont embed...

Just be happy it was the TOP spool!

 

[Onemancrew]

Just be happy it was the TOP spool!

I am very grateful for that billrbg.. Lol

 

[Tazza]

I am very grateful for that billrbg.. Lol

I fixed the picture for you.
That sure is some damage right there.

 

[mmsllc]

I fixed the picture for you.
That sure is some damage right there.

I'm glad you found it. Who would have guessed there would be that much damage? wow.