4020 - Steering valve port function?

Glen D Anderson · Mar 9, 2020

Good evening.

What is the purpose of the small line(# 3 JIC) that is connected to the front of the steering valve & the back / top of the priority valve?

I'm planning on testing a steering valve outside the tractor. Sort of a poor man's bench test. I have the pressure, return, and the steering motor ports figured out, just not sure what the purpose of the small port is?

TIA

WTW · Mar 9, 2020

Glen, The line is a drain line for the back side of priority / pressure control valve to keep it from
hydraulic locking on back side of valve spool. It connects to and drains into steering valve. Has nothing
to do with function of steering valve. DW

Bob · Mar 9, 2020

It's the "bleed line" that carries oil that has sneaked past the spool in the flow control valve to the steering gear where it combines with steering valve return oil.

In other words, when testing the steering valve that port can be capped.

Cliff Nelson · Mar 9, 2020

It is a bleed/vent line for the priority valve. It returns oil to the steering valve housing which then returns oil to the trans filter housing via a different port on the steering valve. Just cap that fitting for bench testing.

Glen D Anderson · Mar 10, 2020

Thanks for the info. gents!

Glen D Anderson · Mar 17, 2020

Good morning.

Due to constant, erratic steering operation this summer I re-sealed the steering motor from our 4020 & picked up a rebuilt steering valve.

I tested the steering motor using the SCV from another tractor to cycle it back a forth. Everything checked out good with smooth operation and no leaks.

To test the steering valve, I connect the work ports to the motor & supplied the valve with pressure from another tractor via it's SCV. The return from the steering valve was let spill into a pail.

After cycling the valve back & forth multiple times in addition to bleeding it I find that one side is receiving about 450 - 500 PSI less than the other when the wheel is held to full turn. See pictures below for reference. Thoughts???

FYI, when not being cycled, the steering valve does not leak out of the return nor does the motor drift.

2000 PSI supply from another tractor(SCV)

2000 PSI at full right turn

1500 PSI at full left turn

Glen D Anderson · Mar 18, 2020

Glen D Anderson · Mar 21, 2020

TTT

Still hoping someone may have some insight to my question above?

4020 - Steering valve port function?

Glen D Anderson

Member

WTW

Well-known Member

Bob

Well-known Member

Cliff Nelson

Well-known Member

Glen D Anderson

Member

Glen D Anderson

Member

Glen D Anderson

Member

Glen D Anderson

Member

Similar threads