How to Adjust Return Detent on Your Log Splitter Valve
Learn how to fine-tune the return detent on your log splitter valve for smooth and efficient cylinder cycles.
Welcome to the RuggedMade Tech Corner. I'm Jared.
This is the first in a series of videos where we're going to be looking at some of the common hydraulic control valves that are used on log splitters. Now, these can be used for other applications. We've had customers install valves like this on wheel crushers, on forge presses, and on trash compactors, but they are pretty much industry standard on most hydraulic log splitters. And, the reason for that is this return detent function. If you've ever operated a log splitter, you're probably familiar with this. When you want to split a log, you hold the lever against spring tension and when you let go, it returns to neutral by itself. This is pretty much for safety. When you're extending the rod, there's the most potential for injuring yourself or others, so you have to stay paying attention to what's going on. But, when you want to retract it, there's usually less risk. There could be some pinch points but generally it's safer on the retract stroke. So, you can push the lever into this position. It stays in the detent and the rod retracts and when it gets all the way back, it should pop back into neutral by itself. Now that's not an excuse to turn away from the machine just because it's in the detent but it sure is convenient.
Now, this function is also sometimes referred to as “auto-return,” which is fine, but you don't want to confuse that with the mythical “auto-cycle” valve. We've got an example of that here with this Prince RD5200. It has two spools but when set up for the auto-cycle function, it's only going to control the main splitting cylinder. You would start by pushing both levers out and they would both stay in detents. The rod would extend when it gets to the end of its travel, it's probably split a log by then, the first lever is going to pop into neutral and then it's going to retract. And, when it gets all the way back, the second lever would pop into neutral and that would complete a full out and back cycle. So, it's a great design but today we're just going to focus on looking at this valve and its return detent and how to adjust the detent.
So, in order to understand how it works better, we're going to start by disassembling this valve and taking a closer look at what's going on inside. This is the -01 valve from RuggedMade [33-135-VALV-01]. It has 1/2" work ports. Other than that, it's the same as the -02 valve [33-135-VALV-02], which has 3/4" work ports. This is very popular on our log splitters. It's used on a lot of other makes and models of log splitter and it's very popular with DIYers for repairing, modifying, or fabricating their own log splitters. It is very similar in design to this Prince LS3000 Valve and the method for adjusting the detent is the same on both. There are two adjustments that can be made to this valve. Under this big hex cap is the relief valve. This is essentially a bypass that allows fluid to flow through the valve and back to the tank rather than being forced into one of the work ports to do work, in say, a cylinder. It's activated if pressure exceeds the spring tension in there. We're going to cover this in a separate video.
So, today, we're going to be looking at the return detent and that adjustment is here on the side. This is basically a cartridge. It consists of this adjustment screw, this jam nut, and then there's some things inside that we'll look at in a minute. To adjust the detent for routine maintenance, there's no need to remove the cartridge; there's no need to even remove this adjustment screw, but we want to dissect this thing and see what's going on inside, so we're going to remove it completely from the body of the valve.
Here's our detent spring. This is a little tap-it adapter plunger. There's the body of the cartridge. Here's a plunger that has a couple of seals on it. And then, most important of all, is the ball. To remove the spool, we need to take off the circlip. There's a little metal disc here and that will come right off and then here's our spool. Here's the seal. Here's the spring that helps the lever return to center from either position. What we're focusing on here today is this area in here. It would be roughly in this position when inside the valve, and if you can picture the adjustment detent being here, that's going to line up right about here. So, we can put this cartridge back together and recreate what's going on inside. Our spring, plunger … so this can compress against the spring. So that spring is pushing on this, which is pushing on that ball. So there's basically two areas on this spool that relate to the detent.
This flat area represents the neutral and the rod extend positions. When the ball is pushed under the spring tension from this, it's just going to ride along this flat area on the spool as the spool shifts. This would be neutral. This would be extending the rod. Back to neutral. But, now we see there's a ramped lip and when you shift the lever for the return detent, it's going to force the ball up and over that lip and down into this channel or groove where the ball gets captured. And that is why the lever stays in the detent when everything is adjusted correctly. And that's where it comes down to the tension of the spring inside this cartridge will determine how much pressure is required to dislodge this ball from that channel and get it to go back up and over this lip and into this area where it's now free to just be in neutral or extend the rod again.
When we're making an adjustment, we're just going to be moving this adjustment screw in and out, compressing the spring a little bit more or less to control how much pressure is pushing down on this ball to keep it in that detent.
So, now let's move over to the log splitter where we have a valve just like this installed and we can see it in action. So, why might you need to make this adjustment? Well, sometimes people buy these valves for a project and the factory detent setting isn't quite right for their application. Sometimes the wear and tear on these after thousands of hours and cycles of use can change how they behave. And, temperature can also cause the spring in there to behave differently. From the coldest day in winter to the hottest day in summer, its rate can change. So, when you're making this adjustment, the idea is to set the threshold at which it trips back into neutral as low as possible. This is going to reduce wear and tear on the overall system and this is particularly important if you're using something like this, which is a stroke restrictor.
We have one right here on the splitter. What this basically does is tricks the valve into thinking that the cylinder rod is fully retracted. When the rod comes all the way back and there's no stroke restrictor there, there's a pressure spike and that's what helps the centering spring kick this back into neutral. The stroke restrictor, in this case, is going to be hit by this push plate about four inches before the rod is fully retracted and that's going to also trigger a pressure spike and trick the valve into thinking the rod is all the way back. This is another version of that stroke restrictor, but you might be more familiar with this style, which basically does the same thing. This clamps right on to the rod of a cylinder and when this rod retracts, this clamp is going to hit and fill the space before the rod is fully retracted and, again, just like the other stroke restrictor, it's going to trick the valve into thinking the rod is fully retracted. And, this style can be clamped on in different lengths to control your stroke.
All you need to make this adjustment are a couple of wrenches. You need a 5/8" for the adjustment screw and a 7/8" for the GM nut but a couple of adjustable wrenches is fine. You always want to use eye protection when you're working on your hydraulic system, especially if you've recently worked on any of these connections.
Now, bring your machine up to normal operating temperature because that can affect the behavior of the valve, especially with all that hot fluid running right through it. We've installed a couple of pressure gauges. This will help us see what's going on in the system as we make these adjustments. This is a 4,000 PSI glycerin-filled gauge, and there's nothing wrong with installing it if you really want the accuracy, but there's no need to use gauges. This detent can be adjusted by feel with no problems.
There are two situations where you would need to make this adjustment. The first one is the lever won't stay in the detent when it should and the other situation is it's sticking in the detent even after it should have popped back into neutral because the rod is fully retracted. So, let's start with the first one. As you can see, the lever won't stay in the detent. This means the detent spring is set too soft. Shut down the machine and cycle the lever a few times. That will release any system pressure. Loosen the jam nut so we can adjust the screw. Tighten the adjustment screw a 1/4 - 1/2 a turn. This will compress the spring in the cartridge and that will require more hydraulic pressure to dislodge the ball in the groove.
Now, check the function by running the cylinder. It's staying in the detent some of the time but not consistently. Let's tighten the adjustment screw a bit more and do a final test. Now it is functioning correctly. It's staying in the detent until it hits the resistance of the stroke restrictor and then it's quickly popping off into neutral.
Now we can tighten the jam nut. Here we're seeing a pretty extreme example where the spool is stuck in the detent and it just will not pop back into neutral. If your valve is behaving like this, it definitely needs to be adjusted. Loosen the jam nut and back the adjustment screw out. Keep doing this and testing until the lever just barely stays in the detent, and tighten from there. We're essentially recreating the situation from before. It's always better to err on the side of the valve popping out of neutral a little bit prematurely rather than to have one that sticks.
Here's an example of a valve that is functioning correctly but there's still a bit too much lag before it pops into neutral. That indicates that the detent adjustment screw is still adjusted too tightly. So, now that we've got it working properly, we can shut the system down, tighten the jam nut, and we're done.
That is how you adjust the return detent on this style of valve. It's very easy to do, so don't ignore it if your valve isn't behaving right by sticking in the detent or not staying in the detent. It'll really enhance your splitting experience.
So, be sure to stay tuned to our RuggedMade channel for more tech videos on how to operate, maintain, and repair your equipment, and keep an eye out for the follow-on video to this one where we're going to look at the adjustment for this internal relief. Thanks for watching.