Hydraulics theory and operation

[MagKarl]

Only thing I can think of is you're dumping fluid to the sump instead of into the 3PH lift cylinder. We have a similar, if not the same, control. Only difference is mine doesn't have that extra hose to the sump, mine returns to the block. My in/out are using the upper ports, not the side if that makes any difference. Can you temporarily plug that line to the sump and see what happens?

 

[Girdlebug]

I'm thinking along the same lines. I'll give it a shot and post back. Thanks MagKarl.

 

[South]

Dont want to hi-jack this thread but I have the same loader control and wondering if this control has the "float" option. If so, how do I engage it?
Thanks

 

[MagKarl]

South, mine either doesn't float or I don't know how to use it.

 

[Girdlebug]

I really appreciate everyone's help on this. I think I've got it whipped, finally. I ended up tearing the valve completely a part. At some point before I purchased the tractor, someone removed the PB fitting inside the valving. So, the return line and the PB ports share the same fluid. This dumps fluid back to my return vs. sending it to the PB block and my hitch.

It's looking like I'm going to have to probably end up replacing the whole valve. Victor fluid power, the manufacturer of the valve got split up and bought up by different companies. QCC, llc is one of the companies, and I'm working w/ their staff to see if they can track down a part for me. My kubota dealer had the part number from the old bt 1200 manual but couldn't order the part. I should have got that part number from him while I was there. If anyone has that manual, there's an exploded diagram in the back of the manual of the loader control, could you please send the PB adapter part number?

If anyone else has upgraded their loader control, and has parts lying around from the old victor fluid power control, I'd buy the pb adapter!

Thanks again everyone - this site is a great resource

 

[South]

Check this out...

http://www.quadracorp.com/product_detail.php?prod=612

Not sure if its the same, but it might work.

 

[eserv]

I really appreciate everyone's help on this. I think I've got it whipped, finally. I ended up tearing the valve completely a part. At some point before I purchased the tractor, someone removed the PB fitting inside the valving. So, the return line and the PB ports share the same fluid. This dumps fluid back to my return vs. sending it to the PB block and my hitch.

It's looking like I'm going to have to probably end up replacing the whole valve. Victor fluid power, the manufacturer of the valve got split up and bought up by different companies. QCC, llc is one of the companies, and I'm working w/ their staff to see if they can track down a part for me. My kubota dealer had the part number from the old bt 1200 manual but couldn't order the part. I should have got that part number from him while I was there. If anyone has that manual, there's an exploded diagram in the back of the manual of the loader control, could you please send the PB adapter part number?

If anyone else has upgraded their loader control, and has parts lying around from the old victor fluid power control, I'd buy the pb adapter!

Thanks again everyone - this site is a great resource

In the meantime just plug the line going to the transmission and force the oil all to go to the block. It isn't maybe the best but it is the way many tractors are plumbed and they aren't having problems with it!

 

[Girdlebug]

South,that is the same controller! But it was already gone when I called!

 

[Tractor Seabee]

I bought a l245dt w/ a FEL a month or so ago and have been lurking in the shadows since then using the vast amount of knowledge here to remedy quite a few issues. However, one still remains - the weak 3 point lift. It seems like there are lots of threads as this seems to be a common issue, and most get resolved fairly easily. I've slowly worked my way through suggestions to remedy the weak lift, but still have the issue. I'm really new to working with hydraulics, but am slowly gaining knowledge. So I thought I would ask for help both in understanding how the system works, and any suggestions on how to proceed.

From what I understand (in a nutshell) from the hydraulic pump on the right side of the engine, there is a supply line to the same case the 3 point linkage is connected to (not sure of proper name, directly under my seat). From there, is supplied to a small block under the left side of my seat. Two hydraulic lines are tapped into this block and feed the FEL, it's my understanding that one supplies pressure to the FEL and the other sends pressure back to the manifold block from the FEL when the FEL is not in use... it's that pressure that would lift my 3 pt hitch. There is a relief valve on the block manifold i'm describing and the FEL control seems to ahve one as well. Is this correct?

That said, onward to what i've done thus far to try to fix the issue.

- drained tranny/hydraulic fluid and purchased new hydraulic filter. The old one was totally gummed up, and collapsed. New fluid and screen installed, somewhat of an improvement. Will now hold the weight of my back blade - still will not lift.

- cleaned vent tube. Blew it out w/ air compressor. Vent tube is clear, but looking in the vent tube hole with a flashlight - it looks like there is still quite a bit of gunk within the case?

- cleaned relief valve on manifold block next to seat the best I could. Can I verify it's function?

- cleaned relief valve on FEL controls, this one was different than the one on the manifold block, more of a self contained cylinder. I could open the valve with a small file by pushing on it.

- blew out both lines connecting from manifold block to FEL controls.

So, that's where i'm at - the FEL works fine, maybe a bit slow. The 3pt lift will not lift on it's own, but if I lift the implement manually it will hold the weight.

Anybody have suggestions on what to check next, or steps to revisit?
Thanks!
[/LIST]

I have a BX25. I do not have time to read all this thread through so I may be repeating something. You cannot troubleshoot hydraulic problems w/o a guage. W/o you are stumbling in the dark and getting into the old try things till something works syndrome. Also you cannot do this work w/o your models Shop Manual, again you are working in a vaccum w/o. You can make your own guage set for around $50. A tee and a set of quick connects (M&F) and a gauge. Get the Gauge from Surplus center. The QC are Parker series 52, the ones Surplus center won't work; get from you local hydraulic shop. put the gauge in the power beyond line somewhere. If FEL has a relief (shop manual will show) you need to get on the FEL side of the relief. SM you can get from Kubots via your dealer.

 

[MagKarl]

It would be worth your time to read the threads before replying.

A guage wouldn't hurt, but we're talking about a 30+ year old tractor here without QD fittings or PB. We're also working with a tractor that wasn't shipped with a loader, thus no loader content in the manual. Kubota branded loaders in these vintage tractors were made by Woods in the US and installed by dealers here. I have the same rig, and I do have the loader manual but there is no section covering the valve or tractor side connections. The only plumbing shown is the cylinders and hoses.

 

[Girdlebug]

Thanks for the reply Mag. I ended up biting the bullet and upgrading the whole controller from surplus center. The snow in my driveway is piling up here in colorado and needed to get the tractor in service. So if anyone is looking for a controller w/out powerbeyond, I have one for sale. I've learned quite a bit from the endevor - thanks for eveyone's advice.