844xl Loader Plumbing Question (free flow pipe)

[EdR]

After noticing a few leaks and then a pipe splitting I removed the loader from my 844xl so I could get all the hydraulics sorted. Several pipes and filters later I am now looking to put the loader back on.

I have some questions about the pipework. I know next to nothing about loaders, I’ve  put the pipes back on as they previously were;

b1 comes from the hydraulic pump

T1 returns the the auxiliary tank

the previous owners had another pipe running from the T outlet (below t1) to the drain plug at the back end of the tractor. Is this the free flow pipe? Do I need to have it or can I just close off the outlet? What’s the advantages of a free flow pipe? 

I only ask as someone is telling me I don’t need to re-install it, I’m not convinced but want to understand it first.

 

I don’t know what make the spool block is, the plate has worn away and the serial numbers haven’t been fruitful after a Google search.

[nomorejohndeere]

If you leave it disconnected and use the loader does it squirt fluid out?

If you disconnect does it squirt fluid out all the time unless using the loader?

 

[jimb2]

I believe the 844 is an Open Center hydraulic system so the return pipe to drain plug. In an Open Center system the idle state of the hydraulic system is a continuous flow of hydraulic oil from the reservoir to the pump, out of the pump through the various valves and back to the reservoir. If you don't have this continuous flow the pump will be under high pressure all the time and hopefully there is a relief valve in the system or the pump or hydraulic line can burst.
The only reason you would not require that line to the drain is if the auxiliary tank has a line out the bottom to the hydraulic pump but it maybe there to equalize the hydraulic fluid in the diff/trans and the auxiliary tank.

[EdR]

On 10/3/2021 at 3:00 PM, jimb2 said:

I believe the 844 is an Open Center hydraulic system so the return pipe to drain plug. In an Open Center system the idle state of the hydraulic system is a continuous flow of hydraulic oil from the reservoir to the pump, out of the pump through the various valves and back to the reservoir. If you don't have this continuous flow the pump will be under high pressure all the time and hopefully there is a relief valve in the system or the pump or hydraulic line can burst.
The only reason you would not require that line to the drain is if the auxiliary tank has a line out the bottom to the hydraulic pump but it maybe there to equalize the hydraulic fluid in the diff/trans and the auxiliary tank.

Thank you, meant to reply earlier but have been without internet for a few days. This makes sense, I’ve read up on what you said so the pipe is going back on. Really appreciate the response. 🙂

[jimb2]

I was watching a YouTube video on the new John Deere series of tractors and one of the features of the Europe built models there was an auxiliary hydraulic reservoir on the right rear axle and the purpose was to hold additional hydraulic oil for use of a dump wagon/cart that are very popular in Europe. So possibly your 844 being a European model that is the reason for the auxiliary tank.