RK37 Limp Noodle Bucket

[Stikky]

RK37 Shuttle, about 20hrs. Bucket freely moves when back dragging or driving into a pile. Definitely doesn't seem like it should do this but everyone in the RK group on FB claims it's normal. We have several other brand tractors and none do that.

I am NOT in loader float mode, it happens during normal operation as if there's a valving issue or maybe lack of pressure? Any guidance would be appreciated.

 

[Jims1025R]

Stop on level ground, and assure that the bucket is empty. Lift the loader all the way up to the top lift limit. Then curl the bucket toward you, holding it there until you hear the hydraulics "work" just a little more. Then dump the bucket, and again, hold until you hear the hydraulics "work" a little more. Then lower the loader, and press against the ground to lift the front wheels, hold till the hydraulics "work" a little more.

Now try your loader work again, it should be better, if not, repeat. Sometime air gets in the hydraulic system, particularly after lots of dumping the bucket. This will force the air out of the system.

 

[Stikky]

Good info Jim thanks, I'll have my FIL give it a try, tractor is at his house.

 

[DonRybak]

Stikky, as Jim mentioned the FEL needs to be cycled through it's ranges to make sure the cylinders are full of fluid. Here's an exert from the FEL manual.

Make sure the rpm's are raised above idle to ensure the required pressure. I run my bucket through the full curl/dump range several times before I get rid of that limp mode.............Don

 

[Stikky]

Thanks Don,

I'll try it and see what the outcome is. Never had a tractor need to go through a process before working properly. We have 3 other tractors with loaders besides the RK and this is the only one that has this issue.

Do you think the hydro system pressure is set too low? Other tractors will hold bucket position at idle so wondering the cause. Love the RK otherwise.

 

[Jims1025R]

I've had several tractors do this when I've repeatedly used the bucket to scoop and dump without running it to its full motion range in between. Every time you dump, the weight of the load pouring out moves the bucket rather than the hydraulics, so it sucks a little air through a seal. The air accumulates to make the bucket cylinders partly shock absorbers rather that hydraulic cylinders. If for every time you dump, you were to continue to power the bucket in the dump direction until it reached its stop, this would not happen.

My JD excavator does the same thing when repeatedly scooping and dumping...

 

[Stikky]

That's crazy Jim, I've never experienced it before. The RK definitely does it right off the bat but I'm going to try the full cycling thing and see if I notice a difference. We have probably 2,000 hours on our Kubota excavator and has never done that once. Three other JD tractors and none have done it either. Maybe we just don't use them enough I guess?

 

[Grove186]

I noticed the same issue when floating gravel for a traffic pad at our farm. If I held the bucket in the down position just a little bit it wouldn’t do it. I’ll try this tomorrow and report back. Thanks

 

[Grove186]

Running through the cycles like described above worked great.

 

[LD1]

Rural king uses a cheap loader valve that does not have a regen function.

Regen pressurizes BOTH ends of the cylinder. The cylinder still will extend and dump due to the different piston areas between the rod side and the base side of the cylinder. But regen is important for bucket function and prevents exactly what you describe.

What is happening is when you dump the loader....the weight of whatever is in the loader bucket is causing the bucket to dump FASTER than the hydraulics can refill the cylinder. Therefore you create a vacuum on the back side of the cylinder that acts like an air pocket in the cylinder.

If you dump a load and immediately try to backdrag.....you end up with the bucket flopping around.

To cure this you need to dump the bucket ALL the way til it stops.....and continue holding the lever to dump for a few seconds after the bucket actually stops. this refills the cylinder with oil and will make it rigid. Then you can adjust/curl it back to the angle you wish, and proceed to backdragging.

Search "floppy bucket syndrome". You can read SEVERAL tractors have this issue because the manufacture cheaped out on the loader valve and thought regen wasnt necessary.