I am getting ready to order 3rd function kit for my L2800. Can get the kit from Summit for approx $600 on sale this weekend, but would have to source the hoses separately . Or I can order kit with my grapple from EA for $970 which would include the hoses. For those who have already done this, which choice makes the most financial sense or is it a toss up?
3rd function kit
- Thread starter STEVESC
- Start date
If you have a fair priced hydraulic shop near you, you might want to get the kit with no hoses and then measure carefully to get hoses that are routed where you want them. I didn't use the hoses that were with the kit because I chose a more protected route using a great shop in my area, of course we don't know where in the USA you live.
trikepilot
Well-known member
Equipment
B2620HSD LA364/BH65 48SQ Bush Hog LP FDR1660 LP RB1560 B2672 42in forks LP1266
try https://www.discounthydraulichose.com/
I did all the fittings and hoses for adding front and rear aux hydraulics for a fraction of the cost of either of my local shops. They are easy to work with and I got fast shipping (PA to VA) that did not slow me down on the install.
I did all the fittings and hoses for adding front and rear aux hydraulics for a fraction of the cost of either of my local shops. They are easy to work with and I got fast shipping (PA to VA) that did not slow me down on the install.
I don't know of a kit. Do you want the thumb, hydraulic valve, or both?
Last edited:
Adding the hydraulics is easy and not particularly expensive - just a "third function" for the hoe. The thumb is something else.
Dan
I have the Summit kit on my LX2610SU. It's about 3 years old, and I've had to replace one of the microswitches in the control knob. (Strike 1) I've had intermittent problems with it for the past year, but no time to diagnose and fix it. Because of the failure (randomly closing the grapple) I did a little research on the switch and found out they were rated 1A NON-reactive at 30VDC. I haven't checked the current on the solenoids on the valve, but I can almost bet it's going to be higher than 1A at 12VDC. That said, the kit comes with switches that are underrated. Solenoids are VERY reactive devices and will toast a set of contacts that don't have any kind of arc suppression. I found exact replacements for the switch from Amazon and got them in 2 days, but not without some risk to my tractor. I now have 4 more replacements. I pulled up on the lever to raise the mower, and it didn't budge. Turns out the valve was stuck on and stalling the hydraulic circuits because the valve provided in the Summit kit is NOT a power beyond valve. (Strike 2). I thought I'd found the problem at one point when I found that the plastic nut that holds the bottom solenoid on had fallen off and the solenoid was nearly gone with it. I made a new nut with aluminum and solved the problem.
One more little problem with this Summit kit and I'll probably be getting a Kubota kit. I can't risk burning up the hydraulic pump in my tractor because a cheaper 3rd function option fails.
None of these kits including Kubota use a vakve with power beyond and even if they did it would still stall your mower, 3pt, rear remotes, and boom on the loader. So strike strike 2. The pressure relief valve is what protects the pump in situations like that.
Dan
There's gotta be some better plumbing design, or a better valve. The loader doesn't stall everything and the 3-point certainly doesn't stall everything. The herky jerky crap when I'm tapping the 3rd function to close the clamp and lifting at the same time is annoying. Instead of putting the 3rd function valve tank port in series with the PB from the loader, perhaps the smarter idea would be to put it in parallel so that it does not affect the loader at all. I've seen some multi-function kits that stack the banjo bolts for the tank return which makes a lot more sense than letting one valve shut down the entire hydraulic system of the tractor. The PR just protects the boom on the FEL. I read far too often about people bumping up the pressure and breaking things. I'm pretty sure what I read about the Kubota valve said it does have a relief that prevents it from stalling the FEL boom and curl functions. That could have been wishful thinking though.
Oh yeah, the PR protects the pump but does very little to protect the hydraulic oil. That's where all the heating comes from. The lines to the 3rd function valve were EXTREMELY hot by the time I figured out what was going on. That can't possibly be good for the oil. It isn't discolored or stinky, though.
I think yoi need to refresh your understanding of open center hydraulics.
- With or without PB a stalled cylinder stalls all downstream devices and that includes the loader valve
- A relief valve prevents over pressure upstream of a stalled cylinder but it doss not prevent stalling down stream devices.
- Operating any directional valve cuts off the neutral circuit supply to diwn stream valves. They are dead in the water untill the valve returns to neutral.
- Exceptions to 3 are the 3rd function valve and the boom spool on the loader. They are serial valves and pass return oil from the cylinders to neutral rather than tank. That puts the cylinders in series with the downstream device which allows them to operate in tandem but the loads are combined and if any one load stalls they all stall.
- Kubota 3rd function kits use the same D03 valves used by everybody else. NONE of them have a power beyond circuit. A very few have an inlet pressure relief that is essentially worthless given the tractor relief has priority.. And as I said in (2) a pressure relief does not prevent stalling the neutral circuit.
Dan
Last edited:
Maybe not cheaply, but most anything can be done with the right hardware and knowledge. I'm a retired electrical engineer who spent 40+ years in heavy industry and military process applications, most of which had a LOT of hydraulics, so I had no choice but to learn just a bit about the subject. I haven't looked at the entire hydraulics diagrams of my tractor yet, but eventually I will. I can't help thinking a stacked banjo to supply pressure to the grapple valve, and a separate RTT line, or certainly one that parallels the loader spool, would work better than what is accepted as the right way. In fact, the pressure line (short hard pipe) that originally went to the loader valve is removed to install a banjo for the Summit valve, then the return line is piped back to the loader spool input where the original P line was connected. I installed my kit personally, and I know what I put on it, and still have the OE connector for the loader. I have seen other kits that come with two banjos and an adapter that just replaces the connection between the transmission and the loader valve so that the pressure and tank lines for the 3rd function parallel the loader valve. Can't remember where, and it may not have been a Kubota part, but pretty sure I was wishing I had one. I do remember price was part of the decision making process, but won't hazard a guess what the difference was. "Can't be done" is not the same as "Can't afford to do it."
Sometimes, I'm just wishing out loud for a solution that perhaps someone here already has or tried using less expensive parts. Do we just simply accept "It hasn't been done before"? Never in my life have I accepted that as an answer. That was the challenge of my career that I loved. My favorite phrase was "Hol' muh beer, hide in the bushes, and watchiss!" I'm basically an overeducated redneck. I don't like reinventing a wheel, but maybe upgrading the tires isn't a bad idea. "It can't be done" is not in my vocabulary.
I am intimately familiar with that plumbing. You have an open center system and it does not work like you think. Your fundamental error appears to be confusing tank with neutral. That should be enough to make you think twice and consider picking up a book on hydraulic circuits. In particular open center directional control valves.
That does not mean you cant redesign the circuits. To do what you envision you need a pressure compensated flow divider. That divides the neutral flow into two independent parallel circuits and has absolutely nothing to do with tank connections. That of course substantially reduces the available flow (volume) in each branch. You may discover your cure is worse than the disease.
Dan
Last edited:
If you have a particular reference that you feel worthy of reading, that would probably help me resolve some of my ignorance a lot quicker than just telling me “it can’t be done “ and that I’m wrong or mistaken. Anything in addition to the full hydraulic schematic of my tractor would be helpful. Most things I can find for myself, but I like to know what reference an expert can rely on. What’s your Hydraulics Bible?
This is a long term goal, not an instant gratification. Instant gratification is rarely permanent happiness. If I find a way then I can share it and make all of the lives of people with 3rd function valves richer. I LIKE studying things that I don’t know. That’s how I get to know things and become less ignorant. This is not one of the times that ignorance is bliss.
EDIT: BTW, isn’t thinking twice EXACTLY what I’m doing? I thought it was.
Ignorance is not bliss. It is an unnecessary self imposed handicap. I applaud your mindset.
I don't have a reference but they are not hard to find online. But we can easily cover the fundamentals here. Lets start with something simple. Here is a diagram of an open center circuit similar to your loader third function. Ask a question and I will try to answer it. One question at a time and keep the question short and specific. I will start by telling you that with ALL valves in neutral ALL flow travels around the outer circle. Red is the neutral circuit, blue is the tank circuit and both circuits are at "zero" pressure.
