305c swings to fast

[nowing75]

I'm working on a 305c s/n hwj cat excavator. It swings to the left twice as fast as the right. The spec is 3 revolution and I get 10.5 sec to the left and 19.5 to the right. The spec is 19.5 sec. When turning to the right it takes a lot of pressure to get to start moving and to the left takes very little psi. I swapped the relife valves in the motor but no help. I checked the brake pressure it is in spec both left and right for psi. Any help would be great.

Jason

 

[hvy 1ton]

The more i think about this the more confused it get. It'll be interesting to see what everybody comes up with. Good luck and hopefully somebody smarter than me comes along soon.

 

[lantraxco]

Put the truck on the left side.......

 

[nowing75]

Yes that would make cycle times look really good. I got dizzy on the 3rd revolution.

 

[RZucker]

Broken centering spring or popped snap ring on the valve spool?

 

[Mark250]

tee into the swing valve pilot lines at control valve and check pilot pressures. also check you have equal travel at LH joystick
Mark

 

[DK88]

Can you swap the motor ports?

 

[W Welding]

I have seen similar problems on track travel speed. Turned out to be the spool travel limiter. adjuster in the cap on the end of the spool. It had turned itself in and limited the amount the spool valve would travel and slowed the track way down, the pressure test to spac but didn't have enough flow. Maybe yours is letting to much flow.
But that was on a John Deere 653g, not sure if cat uses something similar.
Just a thought. Good luck

 

[nowing75]

Thanks for the info. I'll have to see if in can swap lines at valve might need to make a jumper.

 

[nowing75]

Finally got around to working on the swing issue after extensive testing and pulling what little hair I have out they have a 304 mini so I pulled the spool out and put it in and works fine turns out somebody had changed the spool in the valve causing the problem but to just look at the spool and a valve everything appeared to be fine. I'm sure glad that's finally over with as I had even the cat guys scratching their head