Valmet 646 hydraulic woes

[kiko]

I hope this works. If it does this is a break down of a k 170 valve. 01b is the tiny pilot filter.

 

[kiko]

Yes!! I finally figured out this picture thing, and all I had to do was follow the directions. It's on now!

[snowstorm]

Yes!! I finally figured out this picture thing, and all I had to do was follow the directions. It's on now!

thats a rexroth valve used in a 646??? dosnt look the same

[kiko]

I know nothing about a 646. I was only making the point that there should be some sort of pilot filter. With the parker K 170 valve the pilot filter is in the end section with the pressure reducing valve. This was a "for example" situation. All the pilot operated systems I have dealt with had pilot filter. Some systems have the pilot filter located in the accumulator charge valve that provides oil to the pressure reducing valve.

[snowstorm]

i have my 646 in the garage. so i did a little research. the pilot psi is 550. you do not check it at the valve behind the cab. there is a cover about 5' long just above the rite ft tire. there is a test port there also what looks like an in line filter.

[snowstorm]

might also want to check the coils. mine didnt shift the gear box replace the coil ($30) now it shifts as it should

[leeroyjd]

Thanks for all advice.
  I managed to break off allen head in blade primary shuttle and did'nt have a good enough drill bit to get it out! It looks like I missed checking this one somehow.
  Snowstorm,you may know this is the blade section which is the first section in the valve bank.If there is bypass at the primary/and/or secondary shuttles will this effect hydraulic flow anywhere after that?
  Thanks,Lee

[snowstorm]

i have been told that if one shuttle is bad moving the valve next to it will make it work. you need a good 3/8 drive 3/16 allen always hit it with a hammer that will help break it loose. the coils are on all the elc over hydra valves. you have diff locks gear box crane netural ect. if the coil was weak could it cause the controls to chatter? the crane netural coil. the 646 is not a simple fowarder not as complex as a new one but it sure aint no old timber jack or tree farmer

[leeroyjd]

   Got  coils on the way,although the float appears to be working fine.When you activate float switch you can feel it in joystick,just a quick pulse.Sound the same to yours?
   Both the grapple open and extend out functions have a delay.It is not the switch at the joysticks so it is either bad wire or a  faulty solenoid at valve bank,right? If so do you think this could cause these hydraulic issues?
   I'm going to set up gauge for pilot pressure while I'm running it to see if there is a drop or spike when it makes this noise/vibration.
New primary and secondary shuttles made no difference.At least that is ruled out.Most needed replacing anyhow.
  Leeroy

[snowstorm]

my bucket is only slow in cold weather. no delay when warm. what i was thinking if the coil is weak for the crane netural valve it may chatter. try to enguadge. i replaced the onefor the 2sp gearbox. sometimes it would try to shift. but it wouldnt hold it in. new coil all is good. what was your pilot psi? did you look at that filter?

[leeroyjd]

Been away from computer, all pressures are okay,problem still unresolved.I'm going to check the spool in unloader valve this am to see if it is stuck.Anyone had this happen?
   Thanks,Lee

[snowstorm]

everything checks out ok but it still dose it?

[leeroyjd]

     I bought two new gauges 4000 psi and 1000 psi and pressures are right where they should be . previously used 6000 psi gauge which I now realize was not accurate for the lower readings. 120 standby 550 pilot 2750 main relief and all the function settings are right on.
     If you hold your hand or press your foot against cab interior next to valve bank while loading you can feel slamming.Could it be the relief valves opening and closing because main spool is sticky or stuck? Raining so I don't think I'll get to it this am.