John Deere 5720 2003 model, loose hydraulic power when breaking

[knutmartin]

Hi
I have some trouble with my John Deere 5720 2003 model.
I bought it used with a frontloader, (should not be the issue).
We was not happy with the way the hydraulics worked so we bought the "kit" John Deere have fitted to the 5020 series (valve that stop flow to the hydraulic trailer breaks), but it didnｴt help much. So we payed to get the largest hydraulic pump, but made no difference.

The problem is that when I hit the break, steering gets hard. If I steer or I apply a bit of pressure on the break pedal, I can not use the frontlift.
My dealer can not help me and they have measured the pump etc. and say everything is fine. But I tried a 5820 2009 model and it is a different world.
Do you have any suggestions?

 

[jenkinsph]

Has anyone measured the pressure to the various ports while you are having this problem? There is a priority valve which shifts all flow to the steering and brakes when the pressure drops below 1900 psi IIRC at least on the older closed center systems. You could also have other issues with the pilot valve sensing.

 

[knutmartin]

Has anyone measured the pressure to the various ports while you are having this problem? There is a priority valve which shifts all flow to the steering and brakes when the pressure drops below 1900 psi IIRC at least on the older closed center systems. You could also have other issues with the pilot valve sensing.

I will check this as soon as I get the time.

My guess is that the priority valve is damaged or the spring is broken, or mailfunction for some reason. If anyone have partnumber for the spring, valve part and seals I need I would be very thankful.

 

[jenkinsph]

Did you look at JDparts online?

John Deere - Parts Catalog


Look at the selective control valve section, I had the priority valve pinned but it goes back to the main page.

 

[knutmartin]

Thank you, will have a look.

 

[knutmartin]

The online spare parts cataloge was great, but would be even better when i get home and can use a bigger screen than my 13" laptop.

It looks like its a kit with spring and seals that i quite cheap, think I will test that on the priority valve. I thought it would be a priority valve located close to the pump, or is it normally only the one located at the back with the hydraulic quick couplings ?

 

[knutmartin]

Did you look at JDparts online?

John Deere - Parts Catalog


Look at the selective control valve section, I had the priority valve pinned but it goes back to the main page.

I have now ordered the Spring and seal kit: AL167496 and will mount this tomorrow.
Any input on how to do this, or is it as easy as it looks?

 

[Tx Jim]

This is the only priority valve shown in PC. AL167496 is parts key 21 Is your tractors brake valve single or dual stage??

 

[knutmartin]

This is the only priority valve shown in PC. AL167496 is parts key 21 Is your tractors brake valve single or dual stage??

I am not sure what you mean by singel or dual stage, please explain.


edit: did read your answere a bit quick before my reply.

 

[knutmartin]

I am not sure what you mean by singel or dual stage, please explain.


edit: did read your answere a bit quick before my reply.

Did change the springs and seals his evening, and I looked like it worked. Did get a leak on one of the large seals so got late and will test the tractor more tomorrow.

If it works, it's amazing what parts for 40$ can do