Well today, I was just about to rock and roll with my mulcher, some hurricane debris and as I was travelling over to the enormous pile, the steering joy stick went wonky and would only go right, Then the display lit up with "hyd valve bank spool centered pressure detected' After some repeated attempts to to engage the safety lever I was able trick the hyd lock to get temporary hydraulics to lower the boom and release hyd pressures. Upon further investigations it seems there are these likely culprits. 1. The left swing spool is actually stuck (It has been drifting some which for a machine with less than 1000 hrs seems abnormal) 2. The relief valve is stuck open. 3. According to the service manual, The "centered pressure sensor" may be defective. Looking at the main valve body I only see the main pump sensor, the calibrated sensor and the left and right travel sensors on the rear of the valve body. This doesn't seem to make sense since when I can temporarily trick the machine into engaging the hydraulics, the other hydraulics work fine. Just the left swing is gone into right swing mode. Fortunately I moved my work truck away from the machine so when it goes into the righty spin I didn't wollop the old dodge. My thinking is that where ever the centering pressure sensor is it would effect all the hydraulics not just the left swing. So this leaves me with the 2 directions to go in my further investigations. Remove and inspect the left swing relief valve. Remove and inspect the left swing spool. The only thing that slowed me down on that was how to stop all the oil that most likely will come draining out of the valve body when I open it up. Draining the system is going to be a drag out in the field but after the hurricane a couple weeks ago, what could be worse. Any tips on what I have got myself into or does anybody want to come to kauai and be my mentor/mechanic. I'm seriously feeling too old for all of it !
Lots of information provided but missing the machine Serial Number. That snippet makes it easier to track down information and troubleshooting procedures.
308C GG806182
You obviously have access to the same information that I do. It looks as though this one will require the services of Cat ET diagnostic software. 2532-2 - Event is active when the machine ECM has determined that an implement valve spool is not in the centred position when expected. In other words if all commands are in neutral. If the bypass solenoid is disconnected, it will also cause this event. Check for this first. Use extreme caution troubleshooting this event. It is intended to identify a spool that is stuck outside of the neutral position, which can cause machine motion with no control input. Follow the steps below to identify the cause of the event. 1. Check the wiring to the bypass solenoid on the implement valve and ensure that there is a complete connection. 2. Ensure that machine is in a condition where it is safe for full implement motion. With the engine running at throttle dial 1, raise and then lower the arm bar. Use extreme caution when lowering the arm bar as implement motion can occur if the implement valve spool is stuck. 3. Is hydraulic functionality restored when the arm bar is lowered? If NO, raise arm bar again and check the Hydraulic Valve Bank Spool Centered Pressure in ET. If the pressure is between 400 and 1200kPa, a spool is likely stuck out of the neutral position. If the pressure is greater than 1200kPa, replace the Hydraulic Valve Bank Spool Centered Pressure sensor. If the pressure is below 400 kPa, one of the solenoids on the implement valve is likely stuck. If YES, operate each function one at a time and look for any abnormal response to commands. If the problem function is not identified, repeat the entire Main Valve Calibration in service menu of ET. The valve calibration has a process to check for sticky valve spools and can provide better detail for which spool may be the issue. If no faults trigger during valve calibration, download an ECM replacement file. The ECM replacement file contains hysteresis valve currents for each valve function. Abnormally high hysteresis values indicate a potential spool problem.
Thank you Nige for the information. Yesterday after trying to get some help from the local Cat dealer to no avail, I dug into the situation. Fortunately, it wasn't raining for a change and I could open up the Hydraulic valve block assembly. First I drained the hydraulic tank and removed the hyd. tube that runs in front of the lower solenoid block which is where the suspected stuck swing spool is located. I had already previously removed the cover and cover support to gain access to the solenoid bank to check the connections. There were also 2 small hoses attached to the left side of the solenoid block that had to be removed. Once I unbolted and removed the lower solenoid block I was looking at the problem child swing spool and its neighbor spool which I don't recall what it's function is at the moment. The swing spool was indeed very stuck and could only move in and out about 3/4". The neighbor spool to the right slid in and out with precision and ease. At that point I was relieved to at least found the culprit. Removing the swing spool however was not an easy thing. I was concerned that too much elbow grease to attempt to remove the spool might damage the housing which looks like an expensive and difficult project to remove and replace. I was finally able to reach a cat service manager on another island who was kind enough to engage with me on my dilemma of spool removal. He confirmed that I could possibly damage the housing in the removal process. I debated with myself on whether I should remove the back cover of the valve block which hopefully would give me the option of tapping the stuck spool out from behind. I had not cleaned the back of the valve block like I did the front before starting so that was another issue I had to sort out. I ultimately gave in to just pulling harder on the swing spool with a vice grip attached to the nut on the end and with some praying, cursing and sweat I finally wiggled the b*****d out. It seemed to have some defect which was causing it to not slide freely like its counterpart spool to the right. I took the right spool which was sliding like it should and tested the swing spool port with it and it slid in and out just fine. This confirmed that the port was not the problem but the spool was. I tried to get ahold of the local cat parts dept. to see what was available and when, but the parts man quit recently and moved back to the mainland so I tried the Oahu parts department and they were also too busy and never called me back. So, I recall someone in another thread I recently read had used some abrasive compound to re-hone the spool or the port. I was reluctant to introduce any abrasive to the port as that just seemed wrong wrong wrong so I took the spool back to my shop and went at the spool with my dremel with a buffing bit. There was what seemed like a little damaged or discolored area near the end of the spool. It was very slight and I had to use a magnifying glass to even see it. After working it over for a bit with the buffer I took it back to the machine and it actually had helped free up the spool in the port to where I could now slide it back in, however still with way too much resistance (compared to the other spool). After massaging the damaged spool for another hour or so with the dremel buffer I got it reasonably well moving in the port. Not wanting to leave the valve assembly and various tube and hoses open (another hurricane and rain on the horizen) I went ahead and buttoned everything up with the exception of putting the hydraulic oil back in the tank. So, now I have to decide, do I put the oil back in and see if my jury rig repair works, or do I just wait till monday and try to find the new spool from somewhere. I guess the question is how much resistance can a spool have before it gets stuck? The other question would be what caused the spool to get damaged and stuck in the first place? Since this is my first spool service experience in 50 years of owning and fixing heavy equipment, there must be someone out there who has been it this situation and sorted it out.
I’m glad that you got to the bottom of the problem but unfortunately for you a replacement spool is out of the question. The reason is that each spool is lapped into the bore in which it fits, so the only thing the dealer will sell you is a complete valve section. Make sure you’re sitting down when you ask the price..! From the photo of the damaged part of the spool I would say that it has been jammed by a shard of metal from somewhere else in the system that found its way into the control valve. TBH if you have succeeded in loosening up the spool a bit with what you have done so far the best I can suggest is to keep on doing that. Maybe if you can get hold of some engineer’s blue it would help you identify exactly what part(s) of the spool are tight in the bore so that you could concentrate on those areas.
Thanks again Nige, That is a shocker that I would have to buy the entire valve body. Funny thing you mention the "engineers blue" because the whole time I was trying to hone the spool back into shape I was remembering my father (a machinist and millright) having that around the shop to do exactly what I was trying to do by eyesight. I was wishing I had some at that time. Where is the hyd. filter in all of this. Assuming the filter would catch a stray piece of metal then the source of this is between the filter and the valve body. I would assume the circuit is from the tank to the pump, then through the filter and then to the valve body. At least thats what my common sense would say but that may not be the way it is. Now that I am freaked out that there could be some component in my system falling apart and sending chunks of metal into the valve body....yikes
Do you mean where in the circuit does it fit.? In excavators such as yours it is normally located in the return line back to tank. See the attached hydraulic schematic. I wouldn't get too worried at this point. The fact you were able to remove the spool relatively easily indicates that whatever went through that section of the valve wasn't very large. It may pay you to get a sample of the hydraulic oil analysed. That might tell a story. It's not that expensive, enquire with your dealer.
Well folks, after Nige informed me that I won't be buying a new swing spool without the entire valve block and the cost of such a hunk of impressive machinery, I decided to oil the machine back up and see if my dremel buffing the spool handy work was sufficient for the machine to run again. Low and behold it made a lot of strange sounds, purging the air out but it no longer was throwing the E2532 code and was behaving normal again. Using the engineers blue if I had it at the time certainly would have helped me to re-hone the spool to better precision but I got it good enough I reckon and I am certainly thank full for that. I am going to have the oil tested as Nige suggested and take it from there what to do next. It's a wake up call to now know just how vulnerable a machine is to one tiny speck of metal floating around waiting to wreck havoc ! Thanks Nige for your knowledge and assistance.
I should have explained a bit more carefully. As you already know from your polishing work the spool is extremely hard, the cast body of the valve section not so much. During final manufacture the exact diameter of the spool is measured and based on that measurement the tunnel in the valve body is then honed (generally to a tolerance of something in the region of 0.0005" - 0.001") to give the required fit of the spool in the tunnel. At this point the body and spool become a "matched pair" because of the process used during manufacture to ensure the correct fit of the spool in the tunnel. That is why the spool is not available separately, or the valve body for that matter.
Well, it looks like Cat has made this spool available after all. This morning, getting ahold of a mainland cat parts dealer I come to find that the swing spool is available by itself for about $238. The entire valve block is over $15k but somehow they do actually offer the individual spools etc. For now, I am going to run it as is and see if it hangs up again. That news and the current hurricane moving away from us is an encouraging start to a new week. Below is the parts diagram for the valve assembly.
There's a first time for everything and I'll be honest it's the first time I've seen a valve spool offered as a separate spare part on a Cat machine. That'll pay me to check in future........
It's all good. It's a constant changing world and not always easy to hang onto it's tail. Thanks again for everything