strange hydraulic problem, can anyone assist.

[Rob]

hi everyone
just a short question about hydraulics.
I got my FEL loader all fitted now to my B6000 and all seems fine but for one thing, the lift rams are very slow on lowering when using the spool valve with the hyd pump running.
The rams are the original 1 way operation for lift and gravity lower, they work great on power lift and lower fine on gravity only with no pump running, but are really slow and allmost stop completely with the pump running and using the spool valve to lower them.

also what happens with regards to air in the system, shurely with single action rams that are empty, will they suffer from air being trapped in the ram when the oil is introduced to fill the ram as it wont get pushed out , instead act like a cushion and make the rams feel bouncey...

any suggestion to a possible caause.

thanks in advance
rob

 

[Bulldog]

You might try lifting the bucket just a little and with the engine off barely crack the fittings loose on the rams to see if oil or air comes out. Just be sure to not let anything be around or under the bucket when you do this. Most of the time the hyd system will bleed the air of on it's own but some times they can be stubborn.

 

[handyman]

I agree with bulldog and be totally out of way feet hands kids animals because it will go down and not back up if something is under it and its not running. I agree with bulldog.handy

 

[Rob]

thanks for the replies guys on this one.
I've tried a few things along with your suggestions but the prob still remains.
doesnt seem to be much air if any in the rams now, strange really as the lift is strong with the pump running and the rams lower really well and smoothly on a gravity only no pump situation , but lowering under gravity with pump running is very slow allmost stops aswell.

might it be a spool valve issue, i have noticed that if i lower the fel with pump and then raise the 3 point hitch the rams then start raising the loader up quite quickly.

any thoughts

Vic, i await your expert input and i'm standing by.....

thanks
rob

 

[Bulldog]

Have you retraced the plumbing to make sure that everything is routed correctly? It almost sounds like it's fighting against itself.

 

[traildust]

How old are the control spools, are they brand new? Maybe they are by-passing alowing pressure to go around when you are trying to lower.

 

[Butch]

I'd recheck the plumbing.... the wierd interaction between the 3 pt hitch and the abrupt "raising" of the fel lends me to think there may be a line bacwards possibly on the valve or the block that connects the fel valve to the hydraulic system main line... Just a thought... good luck and keep us posted Butch

 

[KubotaTech]

Where do you have your return line hooked up to? If it is a system that uses gravity lowering, your return line should go back to the sump, not to the next hydraulic option in line. It should have a separate line that goes to the hitch or any other hydraulic option. Many loaders have a pressure line to the valve from the pump or relief valve, a line that goes from the valve back to the transmission, which is a return line, and also a power beyond line which goes from your loader valve to the next hyd. option in line which would be a hyd. remote valve or 3 pt. hitch normally. If the lines are not hooked up correctly, such as your power beyond and return to sump would be switched, the loader will not operate correctly. Does the 3 pt hitch operate correctly?

 

[Rob]

thanks for the continued replies guys, really appreciated.
stepping back a bit , here is my layout.

I used the method of using the pressure line from the pump to the rear hitch, rather than acctually cutting into the line and possible messing things up i used the folowing method to get hooked up into the system.

I removed the original steel line from the pump to the rear hitch/spool valve and replaced it with two flexible hydraulic lines both using elbows with banjos etc. One pipe goes from the pump outlet to the port marked (p) on the spool valve, the second pipe goes from the rear hitch/valve into the port marked (T). now that effectively does the same job as cutting into the pressure line and adding connections there and saves me damaging the original steel line.

The spool valve is quite old , same age as the tractor i would say, but does appear to be working ok with no leaks etc. Just to clarify, it is a double spool valve with one single acting valve and one double acting valve.
The lift rams are connected to the first spool which is the single acting valve with the bucket rams connected to the second spool which is two way(although the rams are not fitted or connected yet so there is a loop line connected to the two ports to save losing oil if the bucket ram lever is accidently moved.

The 3pt hitch works fine and the lift rams work fine as allready described in the thread.

In conclusion so far , maybe there is an issue between the gravity lowering single acting setup and the two way setup all working together on the same pressure line, I'm not sure to be honest. What i do know is that the K450B loader when fitted to the B6000 does run with both setups, one with just lift rams and trip tip bucket connected to the rear hitch spool and an updated version which has 2way rams fitted to the bucket whilst retaining the single acting lift rams, although i dont know the spool valve situation for this setup.

I hope that clarifies things a bit more and that you can help me resolve the mystery problem here.

thanks
rob

 

[KubotaTech]

Your valve port marked T should go to a return line back into the transmission. There should be a PB line that you connect back to your hitch. The T line is for a direct connection to return the fluid while dumping or lowering. You hooked this to your hitch, so actually the return fluid from the loader is being forced back to the hitch, causing back pressure in the line. To try it, take the line off of the hitch and stick it in the hyd fill cap opening, then try your loader and see if it is any different.

 

[Rob]

thanks for the update.
one thing comes to mind though, if i connect the (t) line directly back to the oil tank instead of via the return on the hitch control/valve how will i control the 3pt hitch and what then connects to the original oil pressure line input .

i take that by PB you mean power beoynd, and how do i address problem,do i need to run another line from the spool or pressure line.
or, have i missed something here..............


rob

 

[Rob]

Where do you have your return line hooked up to? If it is a system that uses gravity lowering, your return line should go back to the sump, not to the next hydraulic option in line. It should have a separate line that goes to the hitch or any other hydraulic option. Many loaders have a pressure line to the valve from the pump or relief valve, a line that goes from the valve back to the transmission, which is a return line, and also a power beyond line which goes from your loader valve to the next hyd. option in line which would be a hyd. remote valve or 3 pt. hitch normally. If the lines are not hooked up correctly, such as your power beyond and return to sump would be switched, the loader will not operate correctly. Does the 3 pt hitch operate correctly?

I 'm starting to get it now, so as i see it, the 3pt hitch is effectivly now the last control valve on the line after the loader control valve.
so to supply a direct pressure feed now to the the hitch could i put a tee peice into the original pressure line so it feeds the loader valve and hitch valve and then connect the return supply to the trans fill point.


Or, i could remove the plug on the aux output on the 3 pt hitch and use that as the supply to the loader valve and the oil return to the oil fill plug as the loader valve will now be at the end of the line .
(but i'll loose control of the hitch without a control cock on the aux outlet).


Or, i could dump the original fitment gravity lower lift rams and go with 2 way items in which case my current setup will work, is that correct.

Am i getting there now or still talking rubbish

 

[Butch]

The spool valve.... what is the manufacturer of the valve. Got pics? That would help.... Butch

 

[Rob]

Thanks guys, I'll take some pics this morning.
In the meantime, i'm pretty sure vic that the spoolvalve is a 3way device with nuetral centre flow through becuase the the rear 3pt works perfectly and both spoolvalve segments (lift and bucket) are spring loaded and centred.


anyway i,m off to get my breakfast and i'll check back shortly.

rob

some pics of my B6000 earlier this year, plus some spool pics.


http://s807.photobucket.com/albums/yy358/Redsps/

 

[Rob]

anymore thoughts on this one guys, I need to get the project finished so i can start using the loader soon , any input on which method I should use to resolve the issue would be appreciated.

thanks
rob

 

[Butch]

Gonna have to leave this up to Vic on this one.... Butch

 

[Rust Addict]

Hydralic and Electrical Circuits are tough to trouble shoot without diagrams, more so when the equipment is modified and not available to trace out with your own hands. If you've got time enough to draw one of your homemade circuit on this tractor, it could help for others to see what your working with. I'd say this would be the fastest way to get you past the guess and check approach.

 

[cappys tractor]

do u have a valve like this on the top of the 3PH piston cover? This is how I get my HYD fluid out, and as mentioned, The return goes directly into the cap for the gear case. This is not really a professional answer, but it does work.

This is the other view top down of the valve with the return going to the gear case.

This shows the location of the topo of the piston. The 6 bolts come out, and you can pry off the top if you ever have to change the piston Oring. The symptom is a slowly falling 3PH. Just thought Id throw that in there.

 

[cappys tractor]

Rob: are you using the tractors built in Hyd pump or have you (or someone else) mounted an external pump and/or tank?

My previous pics show the original 3ph lever, with an aftermarket diverter valve. but either way the fluid is shunted, it goes back into the gear case.

The gear case IS this particular tractor's hydraulic reservoir.

 

[cappys tractor]

also, have you found www.yenibiz.com

they're in Belgium, and have lots of parts for these B6000.