753g aux hydro help

[bobcatgrant]

Hello, I have a 2002 753g. My question to all you out there is I currently modified a BOSS v Plow(late 80's version) to attach to my skid steer. Got the hydraulics to work thru my auxilary on the front by plumbing thru female connector and case drain into the original manifold. Works well or so i thought. when the aux hydros are on, the boom wont lift and the bucket cylinder wont curl. Is that the way it is or am i plumbing something wrong? Also is there an aftermarket coupling i can use for the casedrain or am i stuck buying an oem thru bobcat? Thanks in advance!!!!

 

[Bswwood]

When you say case drain, did you plumb the return to the actual small middle case drain fitting on the manifold block, if your machine has a block with case drain, or to the larger male fitting on the manifold.

 

[bobcatgrant]

When you say case drain, did you plumb the return to the actual small middle case drain fitting on the manifold block, if your machine has a block with case drain, or to the larger male fitting on the manifold.

yes the actual case drain in the middle of the aux block. The female on the aux block i have going to pump port on the plows manifold and the tank port going to the case drain.

 

[Bswwood]

yes the actual case drain in the middle of the aux block. The female on the aux block i have going to pump port on the plows manifold and the tank port going to the case drain.

The case drain port is not designed to handle the return flow of the auxiliaries. You need to plum the return line to the top port of the auxiliary block. See if that helps.

 

[bobcatgrant]

The case drain port is not designed to handle the return flow of the auxiliaries. You need to plum the return line to the top port of the auxiliary block. See if that helps.

Originally i had it that way but the cylinders wouldnt retract fully and very slow(single acting with spring return tightened to the max) Still had same issue of no ability to have boom or tilt function when aux hydro were engaged. SEemd like pump labored more that way also. which is why i switched return to case drain which eliminated the cylinder return(now its fully and faster) and pump doesnt seem to labor as much. Still have issue though with no boom or tilt.

 

[Bswwood]

Originally i had it that way but the cylinders wouldnt retract fully and very slow(single acting with spring return tightened to the max) Still had same issue of no ability to have boom or tilt function when aux hydro were engaged. SEemd like pump labored more that way also. which is why i switched return to case drain which eliminated the cylinder return(now its fully and faster) and pump doesnt seem to labor as much. Still have issue though with no boom or tilt.

Being a single action cylinder, I assume you are dead heading the aux circuit to maintain position of the plow witch opens main relief valve. With main relief open you will not have enough pressure to operate lift and tilt. Is it possible to change to double action cylinder?

 

[bobcatgrant]

Being a single action cylinder, I assume you are dead heading the aux circuit to maintain position of the plow witch opens main relief valve. With main relief open you will not have enough pressure to operate lift and tilt. Is it possible to change to double action cylinder?

I was thinking along those lines but the plow manifold has ability for flow thru according to BOSS plow mfg. It has coils for the valves and when you press the switch it energizes the specific coil for cylinder operation and again for release so I'm not sure that's the problem. Boss recommended a flow restrictor on the flow side to slow down speed. I'm wondering if that might be hindering the full flow of aux hydros thus giving the sense that something is deadheading.

 

[Bswwood]

I was thinking along those lines but the plow manifold has ability for flow thru according to BOSS plow mfg. It has coils for the valves and when you press the switch it energizes the specific coil for cylinder operation and again for release so I'm not sure that's the problem. Boss recommended a flow restrictor on the flow side to slow down speed. I'm wondering if that might be hindering the full flow of aux hydros thus giving the sense that something is deadheading.

If it's a flow thru system I strongly advise not running the return thru the case drain. You do not want high pressure on that circuit as it could damage other hydraulic components. I'm not familiar the the boss plow but most flow thru systems will act like that if the flow is in reverse direction.

 

[bobcatgrant]

If it's a flow thru system I strongly advise not running the return thru the case drain. You do not want high pressure on that circuit as it could damage other hydraulic components. I'm not familiar the the boss plow but most flow thru systems will act like that if the flow is in reverse direction.

Hmmm, interesting. I have not alot of knowledge on certain hydraulic operation but i thought thats what the case drain is for , direct line back to tank with no ability to reverse flow