Adding a Two Spool remote -- Do I need to connect "Tank"

[audoguy]

In the attached I have diagramed the OEM and new solution where I have added a two spool valve to create remotes to a TC1925. It seems to work fine as the new valve, like the OEM loader valve, has power beyond. I am wondering, do I need to also connect the tank line to the new valve? what are the risks if I don't? If I do need to connect the Tank port on the new valve, how to I do so? Just a Tee in the existing tank line?

Thanks in advance for any free consulting

Audo

 

[CalG]

YES! You need to provide unrestricted flow to tank. Valves are only good for a few hundred psi internally. The tank line is what bleeds the pressure fluid leakage

I put a cast iron TEE at the transmission dip stick/fill port on my B7200 when fitting a two spool valve.

On the Hurlimann, I found a plugged tap to connect an added loader valve to tank. (LOTS of work to gain acess, seat base and fenders etc)

 

[audoguy]

That is not what I was hoping to hear. All of the lines are stainless so finding a place to tee into them is impossible. As I have it connected now I replaced the stainless power beyond line with two hoses... Between the hoses and myriad fittings, etc it was $$$. I will probably end up doing the same with the return.... Replace one stainless line with two flex hoses and a tee. Thanks a lot for the hint though. I would hate to explode my brand new valve's internals.

 

[npalen]

Could you cut the stainless return line and install a compression type tee?

An example: 27605-08-08-08 | 1/2" Flareless x 1/2" Flareless x 1/2" NPTF Male

 

[kennyd]

The "T" or "OUT" line also usually carries the "waste" oil from the work ports back to the tank, yes it needs to be connected. Quite often there is a port somewhere you add a fitting to rather than cutting into an existing line.

 

[dusty3030]

Tank line just needs to dump back into sump - top of the transmission. Look all over the top of the transmission for threaded plugs or perhaps an inspection plate you could remove and install a fitting in. Run a hose from tank port to said fitting.

 

[dusty3030]

I just looked at parts break down. Perhaps you could fit a tee into the tank port on the distribution block and retain the stainless line then make up a hose to go from new valves tank port to the tee.

 

[Leejohn]

He said it is working now. Sounds like he does not have PB fitting in the new valve.

 

[npalen]

The downside to dumping the return into the top of the sump is foaming. Dumping into the existing return line, if available and plumbed correctly, is a good route and will probably ensure that the fluid is filtered when returned. Depending, again, on how the existing hydraulic system is arranged.

 

[CalG]

He said it is working now. Sounds like he does not have PB fitting in the new valve.

The "gotcha" on no return to tank is that the trouble doesn't show until the valve is asked to hold an overload situation.

Then the leakage pressurizes the valve until the body cracks.