Joystick control valve

[leeroyjd]

   Has anyone had to replace theirs? I've come to the conclusion that mine are shot and causing problems on main valve bank (646 Valmet Forwarder).Not 100% sure but switching right to left has me convinced.
  Having trouble finding replacements or even parts to rebuild.Komatsu dealers say they are listed as "no longer available".They are trying to find other sources, as am I.
  Even the manufacturer of the joysticks,Rexroth, is not coming up with anything.So if anyone has a source to check,let me know.
Thanks,Lee
                       Model:Mannsmann Rexroth 4TH6     .If you see these sticks on another machine please let me know.

[Jamie_C]

They are still listed on the Bosch Rexroth website http://www.boschrexroth.com/mobile-hydraulics-catalog/Vornavigation/Vornavi.cfm?Language=EN&PageID=m4048

If for some reason they don't sell them but still have them listed then i would take the specs and get in touch with another joystick manufacturer. If they are just a plain pilot operated joystick you should be able to find something that would work without too much trouble.

[kiko]

Check out the Surplus Center they have rexroth joysticks for 120.00 each. It may be one their web-site as well:I have the cataloge. Went to their website, put joystick in search block and what you need is half way down the page.

[Gary_C]

Whats your location and what dealer are you talking to about the joysticks?

Roland Machinery in Escanaba sold a lot of those machines and should be able to help you. 906-786-6920

[leeroyjd]

Still have not found them.
I'm not sure about surplus centers one.I believe mine reduces the pilot pressure and that does not.It has seven ports mine only has six.Not sure if one port could be capped? Same port count on a joystick for some Prentice machines that may work-but they are $1100 a piece.
  Roland Machinary and The Oliver Stores have been very helpfull but are getting "no longer available" from Rexroth.I call Rexroth and they are saying I must get them through dealer!?
  The numbers on my Joystick don't match up with Rexroth current order numbers either.
So has anyone had to replace joysticks in any piece of equipment?

[Gary_C]

Are these the joysticks with the rocker switches on the top?

If it was me, I'd tear into them and find out what exactly is wrong. Just "shot' doesn't tell us much.

I've been tempted to change the joysticks on my Valmet 840 over to the mini joysticks but they keep telling me that it would cost thousands of $ but they are electric over hydraulic and they say the controllers would have to be replaced. If I remember right, yours are straight hydraulic.

But I can't believe there are not machines out of service as those 646's are getting old and very well used. But forwarders are a prized commodity and most guys just keep fixing. It's still hard to find a good used one.

[shinnlinger]

If it is a mechanical vs  hydro issue, One of the pilot controls broke off in my hand on my old 690 b excavator and jd had discontinued the part.  My neighbor found a universal joint from mc master Carr and did a little bit of machining and rebuilt the control to as good as new. 
Good luck!
Dave

[leeroyjd]

     Yes- rocker switch on top for grapple and boom extension all other functions are pilot controlled.Pretty simple as far as joysticks go.
I have taken it apart.Spools were scratched for sure.Springs were not broken but could be weak? I assume the bore is also worn? Only thing I've been able to get was a seal kit which made no difference.
  "Shot": lots of noise and vibration at the sticks when multi functioning.Valmet techs believe that there is bypass within the joystick, which in turn is causing issues on the main bank.Oil on both sides of spool was one occurance they thought was happening.For instance when you jib in it comes to a point where it stops and wants to jib out. As if it is fighting itself.Not 100% sure but running out of other ideas.
  I also switched right to left joysticks and this further convinced me.If anyone wants me to e-mail a short movie of the joysticks making noise pm me-further confirmation or opposite would be helpful.

[snowstorm]

my 646 makes sorta the same noise as his. he sent me the video. but its only done it a few times. dosent bother anything. leeroyjd there is a regeneration valve on top of the crane for the stick boom. it also has a speed adjustment screw

[Gary_C]

If it's just the jib function, check the anti cavitation valve on the top side of the boom. They do regularly malfunction and some people eliminate that unnecessary valve. It really doesn't do anything but cause problems.

[leeroyjd]

Snowstorm and Gary-I think you are both talking about the same valve,right?I 'll check it out.The jib was just the function most noticably effected but the joysticks do it on all functions.
   I took a ride to where my JD 653g Has been parked and confirmed it has the same exact joysticks.But John Deere wants $2100 a piece-ouch.
So I'm still looking.Looks like some Bell feller bunchers and Hydro-Ax 211 also have same.Waiting to hear back from prentice dealer.But if anyone has any input with these new developments please advise.

[deutz4]

You have my sympathy. Elec./hyd. system on my Franklin 632 started going bad about a year ago. Parker has stopped making them. Finally bit the bullet and ordered a customized Iqan system. 11 weeks and $4700 later it arrived today. Much more streamlined and simple than the 12 year old original. Heading out tomorrow to install. Dealer says 4 hrs. I'm skeptical.