2005 John Deere 120c slow final drive and dipper

[mg2361]

23.6 idling and while stalling arm

Full throttle?

 

[Doug802]

Full throttle?

Yes, full throttle it stays the same

 

[mg2361]

It is supposed to be 33.8-36.3. Did you measure using #3 on the monitor? If not monitor #3 when you stall arm out.

 

[Doug802]

It is supposed to be 33.8-36.3. Did you measure using #3 on the monitor? If not monitor #3 when you stall arm out.

That is monitor #3. Idling it’s 23.6 using no functions and full throttle using functions and stalling it out it stays 23.6 doesn’t move a digit

 

[mg2361]

I don't have a spec but that should read something like 4-6 at idle and levers in neutral. What does it read with the engine off and the key on? Check #2 also, both key on engine off and at idle levers in neutral.

 

[Doug802]

#2 is .6 at idle. 0 with key off
#3 is 23.3 at idle 23.3 with key off

 

[mg2361]

If you swap the wires between the 2 pump pressure sensors does #3 still say 23.3? If not then you need to replace the pump 2 pressure sensor. If it still reads 23.3 then there is most likely a wiring issue.

 

[Doug802]

When I swapped the wires #3 shows 0.0

 

[mg2361]

That's key on correct? If so, let's start with replacing pump 2 pressure sensor.

 

[Doug802]

That's key on correct? If so, let's start with replacing pump 2 pressure sensor.

Key is on. Gonna order that part

 

[Doug802]

Replaced pump 2 pressure sensor. #3 reads 0 when engine off, key on. 1.1 at idle. 34.6 when revved up stalling arm. Dipper and track still slow

 

[mg2361]

When stalling bucket and watching #2 is it still low (below 33.8)? if it is I go back to my first post and say check the 5 spool side isolation check valve.

 

[Doug802]

When stalling bucket and watching #2 is it still low (below 33.8)? if it is I go back to my first post and say check the 5 spool side isolation check valve.

How do I check the 5 spool isolation check valve? I bought the operation and test manual. #2 stays at 0.6 when curl bucket in and holding. 35.1 when I hold boom back all the way

 

[mg2361]

The operation and test manual section 9025-05 (Hyd Theory of Operation) look for control valve operation. The picture that shows the left rear bottom of the control valve item #59. That cover has to be removed to inspect the isolation check valve. Make sure everything is on the ground, relieve the pressure from the hydraulic tank and put a vacuum on it (or drain it) before removing the cover. Also there will be more than just the check valve under that cover, so remove slowly and watch that nothing drops. The isolation check valve should be the one closest to the end of the control valve.

 

[Doug802]

The operation and test manual section 9025-05 (Hyd Theory of Operation) look for control valve operation. The picture that shows the left rear bottom of the control valve item #59. That cover has to be removed to inspect the isolation check valve. Make sure everything is on the ground, relieve the pressure from the hydraulic tank and put a vacuum on it (or drain it) before removing the cover. Also there will be more than just the check valve under that cover, so remove slowly and watch that nothing drops. The isolation check valve should be the one closest to the end of the control valve.

I found it in the manual but can’t tell from the picture where item 59 is on the machine.

 

[Doug802]

Can you see it from that picture?

 

[mg2361]

No it is not in the picture. It is not easy to get to either. Since you have control pressure (post #16 above) to your pump and no output to either the right track or the bucket circuit then you are down to 2 things. That isolation check valve dumping pump 1 flow to the pump 2 side or a pump regulator that is stuck/sticking not allowing pump 1 to come into stroke.

 

[alaskaforby4]

You got this Doug! I have a 160c and it has developed a slight leak right where MG2361 has the arrow. Its a large block bolted to the side of that even larger block. Its leaking on both sides. I imagine a o-ring or gasket in there has partially failed. It looks like quite the project getting it torn down that far. Let us know how it goes, tell me its easier than it looks

 

[rmllarue91]

Not to highjack but i have similar issue .I got a 160c had lots of issues and previous mechanics two sets of pumps.... I got all the electrical straightened out. Clean tank filters and strainer no metal. Right track and bucket seem normal. Anything on 5 spool / pump 2 pulls engine down. Left track and stick is to fast. Both build relief pressure in spec. I flowed pumps no load at idle pump one 14 gpm pump 2 18 gpm. Will flow at 2000 rpm and then 2000 rpm at 2000 psi in am. Both have same low signal pressure 4.0 when working functions. What should I look for with pump 2 flowing more or not destroking thanks hef

 

[mg2361]

I flowed pumps no load at idle pump one 14 gpm pump 2 18 gpm.

Measure how much the screw on the top side of the regulators stick out on both pumps (spec 18 - 18.5 mm). Otherwise lets just wait and see what the 2000 rpm/2000 psi flow test reveals.

Also, if you would please, when you are ready to post the results start another thread.