Hydraulics Problem

[Anonymous Poster]

I can't get the backhoe on my B20 to lift back into position. It's sitting on the gound and I thought that possibly I was low in fluid but it's fine. The only problem I notice is a hissing noise coming from the auxillary hydraulic system. There is some fluid there so I am assuming there is some kind of leak however I can't tell if it's a hose or a connection/seal. My dealer wasn't able to determine over the phone. Any ideas?
Thanks!

 

[TomG]

I don't know if this is a 3ph hoe, and by 'lift' you mean with the 3ph. First, let me say that the hitch on a 3ph hoe that is properly installed is not supposed to lift. It's extremely dangerous if a hitch can lift with an operator in the hoe seat. The operator gets crushed between the hoe console and the ROPS.

I'm also not sure what is meant by 'auxiliary hydraulic system.' The term makes me think of a PTO hydraulic pump, but that may not be the case.

If the 'hiss' is more like a 'howl,' then it's probably a pressure relief valve, and it's not good to run a tractor for long when a relief valve is opening. The oil overheats. If it's a relief valve, there's a good chance that either the 3ph is in a raise position, or one of the hydraulic control levers (loader etc.) is not centred.

My 3ph hoe gets its hydraulics from a rear pair of lines, which are fed through a control valve. I have to hook up the hoe lines, and then hold the control valve open with a bungee cord to route a continuous oil flow to the hoe and back to the return through the control valve. My 3ph is behind the loader control valves, so the 3ph won't lift while any control valve is operated.

Anyway, I'd get a condition something like you describe if I hooked up the hoses, bungeed the valve open, but one of the hose connections wasn't completely made. In such a condition, there is no return path for the oil except through a relief valve. I also could get this condition if I properly mounted the hoe on the 3ph while the hoe was on the ground. As noted, it's not supposed to raise. If I tried to lift it with the 3ph, the relief valve would just open.

My 3ph mount requires 3 top links to be in place for the hitch to be locked down. The only time my hoe is mounted and the 3 links are not in place is when I trailer the tractor and hoe. Sometimes it helps to raise the hoe above its normal operating position with the 3ph. First thing off the trailer, the link goes back on. If this is a 3ph hoe, you should be 100% clear on how the mount works. It's extremely dangerous if you're not.

 

[TomG]

I had an important after-thought. The hose connections to the hoe should be checked to make sure that the input hose to the hoe is connected to the pressure hose from the pump.

Hoses for double action hydraulic cylinders may be connected either way, but most hoes have definite input and return connections. My hoe manual indicates that a bunch of things get ruined in a big hurry if the hoe is connected backwards.

My hoe came with a tag marked 'pressure' on one hose. In addition, one hose nipple on the a brass housing where the hoses attach to the hoe is stamped 'IN.' I believe that a stamp of 'IN' OR 'P' is standard for hydraulic equipment.

I can test which of my rear hoses gets pressure when the operating lever is forward without the hoe being connected. I just grab a line and push the operating lever. The valve in the female disconnect holds the pressure, and the hose which gets pressure can be felt to stiffen. However, I put short red plastic straps around the feed and hoe input hoses to make sure I don't get them confused.

 

[Anonymous Poster]

Make sure yor hose couplers are connected sometimes they look like they are . After connecting see if you can pull them apart. Also check to make sure the 3ph raise lever is'nt all the way in the up position if the feed back linkage is not adjusted properly the tractor will run on relief. This would also cause the loader to not work properly. Also check the diverter valve position is in 3ph or backhoe? Should be in backhoe position.