Volvo l220e steering problem

[Maxfab]

Have a L220e,
Turn steering gently it turns perfectly
Turn steering quickly or jerk and it 'locks up' and wont turn either direction

Fault will occur if steering is jerked in either direction, stop machine and wait 30seconds fire it up and it will steer (gently)
Have stripped steering valve (orbitrol) and its all clean, no sign of it binding

Any ideas?

 

[DirectTech]

It could possibly be the shift valve is sticking, which is located under the cab.

 

[Maxfab]

Ive removed and stripped the shift valve, no sign of contamination, have resealed and refitted, no change

Started it up this morning and it was steering perfectly, so adjusted steering pressure to 3050psi, confirmed working pressure 3780psi
Then took for a test drive and it stopped steering, steering wheel goes hard, and machine wont physically turn

 

[mikebramel]

What are the pressures before and after the steering valve when it locks

 

[Maxfab]

Pressure at steering valve test port is 3050psi at full turn, when it locks it drops to 150psi,

Pump 2 standby is still approx 380, LS at p2 if i stall the hydraulics p2 goes upto 3780, but it doesnt help the steering

When the steering is working the LS at P2 virtually matches P2's main output pressure,
When it locks LS at P2 drops to 40psi

The shuttle valve and priority valves were clean

 

[mikebramel]

So when the valve locks up you have 3800psi into the valve and only 150 out? Something has to be hanging up or there is a restriction

 

[Steve 650]

when you check the priority valve did you can move it easy in the port ? other thing to check is your check valve in the orbitrol. theres 2 little plug (12-13 mm) up and down, and 2 or 4 bigger ones near the orbitrol hoses. Other thing to check, raise the front wheel and check if the front diff lock reamains on when the trouble occurs, already saw this ir makes the loader hard to turn and lock the steer. If so, swap the diff lock solenoid valve with the hydraulic quick solenoide valve and see what you get. I will start with the front diff test, I just repar a L120E last week and it was the same trouble... diff lock was always on...

 

[Maxfab]

Havent looked at diff lock,

Priority spool moves freely, and have checked the small hole in the end is clear,
Have checked the 2 shock valves in the steering valve with the 13mm caps

 

[Maxfab]

Found problem, P2 compensator was jammed