A Dumb Question About Lift Arms and Rear Hydraulics (Bobcat CT230)

[DaveK OR]

I just got a 3-point mount log splitter, did all the assembly, mounted it, and took it out to test some pesky rounds that I could not split without using wedges. It worked marvelously.

But... with the rear hydraulics circulating through the splitter, the lift arms would simply not raise one bit. Is this normal behavior? While it certainly isn't more than an inconvenience, it means that I need to shut down the rear hydraulics when positioning (or repositioning) the splitter. If it is not "normal" behavior, is it a symptom that I have a hydraulic system maintenance project in my near future?

 

[ericm979]

How are you feeding the splitter? It's common for a spool valve to have both a power beyond port, which would then feed the 3pt hitch, and a tank port. And it's also common for those valves to send all the output to the tank port when the valve is moved from the neutral position. So it's probably normal.

 

[Lstlk2hi]

I just got a 3-point mount log splitter, did all the assembly, mounted it, and took it out to test some pesky rounds that I could not split without using wedges. It worked marvelously.

But... with the rear hydraulics circulating through the splitter, the lift arms would simply not raise one bit. Is this normal behavior? While it certainly isn't more than an inconvenience, it means that I need to shut down the rear hydraulics when positioning (or repositioning) the splitter. If it is not "normal" behavior, is it a symptom that I have a hydraulic system maintenance project in my near future?

Did you check fluid level after it warmed up? Adding the splitter and hoses would draw down reservoir maybe so low the machine won't let the loader work. Dad bought an IMT built in one of the FSR countries, Belarus. It had a 90 degree ball valve inline towards the front loader bucket. To use any rear hydraulic attachments or part of attached unit the front loader line had to be shut at the valve in feed side. It was OK but I worried about loader bucket leak down. That was annoying but nowhere near the damage caused from NO gear grease in front hubs on 4x4 tractor.

After it failed I took it apart and the only lube was a light, then burnt, coating of machine shop cutting oil. There had been other problems due to lack of QC in the factory and this was final issue for the IMT brand. I still feel badly for the couple that came out to the ranch to look at it. Neither he nor I were aware IMT had 2 models until he looked at ours. He had a picture of his...nope, different setup and smaller.

 

[dusty3030]

Normal in an open center system. The valve you are running the splitter with comes before the 3pt in your hydraulic circuit. After the fluid passes through the splitter it is going directly to the tank and not the 3pt.

 

[DaveK OR]

Sorry for the slow reply to this discussion... First, yes, I did make sure to top off the hydraulic system after initial hook-up of the splitter. As I expected, it took close to a gallon to bring the system to the "full" level, consistent with the volume of the cylinder and hydraulic lines that were initially empty of hydraulic fluid. The fluid level made no difference in the performance of the rear lift arms.

I suspect that the replies from dusty3030 and ericm979 are closer to the mark. The rear hydraulics are a Bobcat "factory kit" that I installed so I could run my Woods backhoe, and for that purpose it has worked marvelously. However, without having a close look at how the hydraulic flow system works, I can't be sure if the rear hydraulic system will bypass the lift arm system when it runs. Given that it's easy enough to use the lift arms by shutting off the rear hydraulics, dusty3030 and ericm979 are probably right.

And by the way, the rear hydraulic system is nice. Its control lever allows you to regulate flow in both directions to the "A" and "B" hydraulic ports, and also has detents at both ends to allow continuous full flow out of either the "A" or "B" port (and with the "B" or "A" port serving as a return port). The only downside to this for implements like the backhoe or splitter are that you have the capability of reversing flow through your implement if you push the rear hydraulic control lever in the wrong direction, or mix up the supply and return hoses for that implement. Since running flow backwards through hydraulic controllers is not a good plan, I always install a check valve on the return connector to prevent that situation. As an added benefit, because there is that check valve at the return connector, I am not likely to mix up the hydraulic lines.

 

[Lstlk2hi]

I get so lost on hydraulics, MF in picture is closed, JD is open, case 580 extendahoe is closed(?), Cat D6 will flash fire directly under fuel tank but only when 50 gallons just went in, Cat RD2 no hydraulics and got a flat on it one day. No feeling in the world like cranking a turn and one track carries on straight.

 

[Mike1955]

I love the hydraulics. But it is challenging and hard work

 

[jigs_n_fixtures]

The fluid goes through the loader arms, and

Sorry for the slow reply to this discussion... First, yes, I did make sure to top off the hydraulic system after initial hook-up of the splitter. As I expected, it took close to a gallon to bring the system to the "full" level, consistent with the volume of the cylinder and hydraulic lines that were initially empty of hydraulic fluid. The fluid level made no difference in the performance of the rear lift arms.

I suspect that the replies from dusty3030 and ericm979 are closer to the mark. The rear hydraulics are a Bobcat "factory kit" that I installed so I could run my Woods backhoe, and for that purpose it has worked marvelously. However, without having a close look at how the hydraulic flow system works, I can't be sure if the rear hydraulic system will bypass the lift arm system when it runs. Given that it's easy enough to use the lift arms by shutting off the rear hydraulics, dusty3030 and ericm979 are probably right.

And by the way, the rear hydraulic system is nice. Its control lever allows you to regulate flow in both directions to the "A" and "B" hydraulic ports, and also has detents at both ends to allow continuous full flow out of either the "A" or "B" port (and with the "B" or "A" port serving as a return port). The only downside to this for implements like the backhoe or splitter are that you have the capability of reversing flow through your implement if you push the rear hydraulic control lever in the wrong direction, or mix up the supply and return hoses for that implement. Since running flow backwards through hydraulic controllers is not a good plan, I always install a check valve on the return connector to prevent that situation. As an added benefit, because there is that check valve at the return connector, I am not likely to mix up the hydraulic lines.

The "normal set up, is the fluid leaves pump, and goes to the Front-End-Loader valve, if the valve is in the neutral position, the fluid leaves through a pressure beyond port, then goes to the transmission body, where it runs into the internal passages for the 3-pt lift arms.

When the rear valve is installed, it sets inline before the 3-pt arm passages, and if you have the power going to the rear your 3-pt height can't be changed, unless the rear valve is in the neutral position. The rear power valve typically comes in two flavors, the one with the detents, and one which is self-centering. The one with detents is typically installed to power the backhoe. Because if the backhoe is mounted you typically aren't going to use the 3-pt hitch.

So, not being able to use the power to the rear, at the same time as your FEL makes perfect sense to me.