sudden and violent PTO engagement with new Kubota MX5800

[Seven Gables]

I just explained the answer to this hard engagement issue with electronically engaged kubota ptos when using heavy inertia implements over on the Kubota owning/operating thread. It's easy cost nothing and will save your driveline. Been there.

 

[ptsg]

I just explained the answer to this hard engagement issue with electronically engaged kubota ptos when using heavy inertia implements over on the Kubota owning/operating thread. It's easy cost nothing and will save your driveline. Been there.

I did read your explanation on the other thread, however, these PTO clutch packs also have a spring actuated brake. Once you flip the switch to the Off position, the spring pushes the hub against a friction disc trying to stop it.

Doing the ON/OFF/ON/OFF method, not only will wear the clutch discs by trying to engage/disengage and slipping under a massive load, but will also wear the brake disc.

I'm not 100% sure if this method will do any good to a clutch pack.

These electric over hydraulic PTO engagements systems, usually have a hydraulically controlled smooth engagement feature but for some reason it usually doesn't work that good on some tractors and this is for pretty much any brand out there using clutch packs.

 

[Seven Gables]

You’re right ptsg these supposedly smooth engagement clutch packs don’t do a good job of feathering in a heavily loaded pto implement, engineers need to fix this. For me it was kinda pick the best of two evils. If I didn’t do the on off on off method with my brush grinder and the tractor didn’t stall it was so violent of an engagement that there’s no doubt in my mind something was going to break. All Kubota has now on my tractor and many others is the equivalent of flicking on a light switch, I woon’t sugar coat it, piss poor engineering. This method of on off engagement came directly from my Kubota dealers service manager , there best solution. Now that being said both my cousin and I have identical 2011 M8540 tractors that we use this on off on off method of pto engagement and neither of us have had any issue with it causing other problems, time will tell. It’s a major engineering flaw that needs to be addressed, Ya listening Kubota? B

 

[Memphis19]

Yeah, mine sucks. Every time I bale it sounds like something is going to grenade. I can barely run my brush hog because it snaps the shear bolts more often than not. My rake tends to slip the belt at start up. It is awful. I was hoping the smaller orifice mod would be a big help.

 

[rScotty]

Yep. Sounds like poor engineering. Ag tractors have had clutches to ease PTO engagement for half a century now. And for good reason. Some things - like post hole diggers for example - would be impossible to run without a clutch.

But us country folk have been fixing design flaws on ag machinery for 100 years. So what's a good fix for this one? If the solenoid isn't variable, next thing I'd look at would be finding a way to choke the hydraulic flow to the PTO clutch pac. One way to do that would be to put a manual hydraulic valve in series with hydraulic pressure.

It may be that the clutch pac itself is not designed to be able to slip and still hold up. If that is the case, then we need to put a controllable clutch on the PTO output or PTO shaft. That shouldn't be all that hard to design. In fact, if this PTO problem is common it's possible that someone already makes an add-on PTO clutch.
rScotty

 

[RalphVa]

I had this problem on the JD 4010 (would be a 2019E today). It would not start the "hog" at idle. Had to rev to near 2,000 rpm. Think the resulting jolt of the hog arms popping out was instrumental in disintegration of the front driveshaft Ujoint at 9 years and 660 hours.

JD put gentle engagement of some sort on the 1025R; this and comfortable seat were the only redeeming features of the lemony 1025R.

The JD 2025R's PTO engagement is sudden, too, like the 4010's. However, it can be done at the 1,300 rpm idle speed. Not that big a jolt.

Strange that Kubota doesn't have clutch engagement on all its models.

Ralph