I was posting this under another thread, not related, so thought I'd move it to help others out. Here's my issues: Bucket wont curl in when digging hard clay or pulling on a stump without working other circuits to help it out Bucket curl stuck in the ground (hard Clay) #1 pump is around 3500 psi, I've recently rebuilt the bucket cylinder, no unusal wear or scoring noted. Bucket dump seems to work as it should. Boom down is very weak but boom up works as it should when loaded. Boom down while trying to lift up the machine pump 4500ish PSI. Have rebuild kits for both cylinders, but haven't had time to do them yet. Arm in and out seems to work as it should, Arm in or out with bucket still dug in pump 4500ish PSI. So far I've switched the port relief valves (PRV's) for the bucket curl and (since it was beside of it) boom down. Boom down was the same before switching prv as it is after.
Good day 4500 p.s.i. is about correct, your bucket line is down have you tried pressing the pressure boost? When you measure the bucket-boom pressure try full stroking the arm see if any difference. Kind regards Uffex
I was going to post these on the other thread, but now that we're here, let's roll with it. Let's record cycle times for each function. Then let's record max pressure recorded at end of travel. Before measuring travel speed or track speed, be sure you have properly adjusted track tension. Tracks that are too tight require significantly more energy to run. Gonna be hard to check if your boom won't pick up one side. We've already established that pilot signals were degrading, have you been able to blow out the lines going to the RCVs?
Uffex I went full stroke on all functions, the pressures posted were an average range of what I saw. Most seem to be within limits, just a little low is all. I did try the boost function, but it didn't make a difference in operation or by the pressures in service mode. Thanks FWF It's raining here now, I'll have to get cycle times tomorrow, thanks for the .pdf's with the information. The tracks were tight when I bought the machine, I've loosened them up some, but need to go a little more before testing. I didn't blow out the RCV lines. I was looking for the "P" line first and a fitting with a filter?? Or is that not what I should be looking for? One larger line I pulled from a junction block behind the pedal RCV I thought was supply pressure, but no filtered fitting there. Do i need to pull all lines and blow them out? Based off something that was said previously, and what I saw in the service manual, there's a wear point in the RCV' where mechanical movement activates into hydraulic and the wear limit is 1mm. If that part isn't activating enough, as I understand it, the main spool won't move far enough to allow full pressure?? But could it allow partial pressure like I'm seeing on the bucket curl? Making part of my problem a worn part in the RCV? Could i switch curl and dump lines to verify? Thanks
Did you verify whether or not you have a pattern change valve behind the cab. That will cause all kinds of grief but usually limits to arm and boom. So for starters, are we receiving full pilot pressure to the spool caps? If the spool is getting full pressure, is the LS signal reaching the pump controller? In the previous thread, you stated that the engine was bogging under the load as if the pump controller was failing to reduce the displacement. I think you may have to invest in some Tee fittings and a gauge set. We'll help you go as far as we can, but sensors can only tell us so much.
I do have a pattern changer, I haven't messed with it but believe I'm in iso mode and not backhoe. What is the "LS" signal? I'm still figuring out the acronyms. I figured gauges would be needed eventually so I ordered a 5 gauge set yesterday with what seems like a good selection of fittings and T's. I also bought a couple high pressure guages locally for dual pressure checks.
LS is load sense. When you shift the spool some oil leaks off to stroke up the pump. In the B series, it was negative control which was super smooth. Introduced in the C series they switched to positive control. So a variable control increases displacement as need increases. More spool shift, more load sense, more displacement until the engine reaches max load, then the pump controller throttles it back to prevent engine stall.
Good day If I interpret the post correctly you have low pressure to both Boom & Bucket, arm is OK (4500 p.s.i). when you operate the bucket & arm to the full extreme you have 4500p.s.i, operating the bucket or boom only to the full extreme you only have 3500 p.s.i If you could clarify this point it is easier to understand. Kind regards Uffex
Operating the bucket to curl in I'm only showing around 3500 psi, the boom is still around 4500 psi in both directions, but seems weak when trying to lift the machine off the ground. I did finally get a set of gauges, but haven't had time to hook into any of the systems to verify pressures. One thing I did try today was to reverse the hoses going to the bucket cylinder, at the connection point at the boom. By doing this, moving the right RCV left is now dump and moving it right is bucket curl. What I got was a very strong bucket curl even in hard packed clay and at the end of the stroke it would bog the engine down. When trying to extend the bucket (dump) the bucket still wanted to curl. I could get it to extend by just barely moving the RCV out of the neutral position, but that was all. I'm thinking there's some kind of pressure bypass in the RCV on that circuit or maybe something going on with the spool valve to where its not moving to the full position, at previously stated by FwF?? If this is the case, can the RCV's be rebuilt or just replace only? Thanks.............
Good day Raising the machine using only the boom cylinders is often misunderstood, providing you have full pressure that is all you can have, raising the machine with a combination of boom and arm you are most probable to achieve the goal. Bucket cylinder im not following your explanation so well, first checking the pilot pressure is straightforward see attached, if your main line has low pressure in one direction the most probable cause would be a leaking shock/port relief or a fault with the spool shifting. Fourtunatly the Volvo 210 has only one spool for the bucket, attached some information what to look for. kind regards Uffex
I understand what you did and the results you got. It seems like you need to follow guidance posted from Uffex. Let's see what the actual pilot pressure is to each side of the spool. If possible, take note of pump pressure in relation to pilot pressure. This will give a better understanding of where to look next. One thing , while testing, please record pressures at end of travel. Pump and pilot pressure while the cylinder are in motion are almost meaningless.
Good day I should have mentioned that the spring which holds the regeneration valve closed has been known to give out this can cause a loss of bucket power in one direction. Kind regards Uffex
Thanks for the responses. I'll check as soon as I can and report back.
Finally got a chance to check the main pumps and servo pump. The servo pump was at 510 psi, I adjusted it up to 560 per the book. I switched the bucket curl and bucket dump PRV's and that seems to have fixed my bucket curl issue. I pulled the Travel Right spool out to check it, but didnt find anything. The sluggish forward travel for the right side is still there. The main pumps are showing 4900+- psi for #1 pump, but I have no pressure on the #2 pump. I switched gauges and still showing the same thing. All machine functions are working, so I'm not sure what this could indicate?? Possibly the relief valve on the side of the pump??
Good day You have the very same relief valve for pump one and two, try all circuits to get a reading from pump two. Kind regards Uffex
Just noticed that I put relief valve and I meant the pressure regulator on the side of the pump.
Got bored, so I pulled the regulator off the #2 pump and went through it. The sliding sleeve and the spool were a little varnished. I worked them back and forth with clean oil and they work freely. Nothing else looked out of the ordinary. Reinstalled, bled pump and hooked gauge up to the correct port this time. I only have one fitting and can only do one pump at a time. I also noticed that one of the two pressure sensors (the one I didn't replace just recently) had some wiggle in it, so I replaced that one, so two new sensors now. Now, I have 5500ish psi on the bucket dump and 4900ish on the bucket curl on the #2 pump, previously it was the #1. I have no pressure reading at all on the #1 pump. Now I'm confused......................
Good day You have two main pumps one primarily provides the power for boom - bucket and one track. The other provides power for the arm - slew - and remaining track. If you have low pressure for the bucket in one direction only and full pressure for the boom cylinders, the pump & regulator must be good. The issue is isolated to to the bucket circuit, its a little difficult to follow how you jumped to the pump regulation. The 210C display in service mode gives the main pressures. Kind regards Uffex
Good day, thanks for the info on which pump does what. My thinking was #2 providing pressure to the bucket circuit was how the system worked, but I was unsure when I was getting pressure only from #1 when moving the bucket. But then I realized I was measuring pressure from the wrong place, the book is hard to follow sometimes. I have good pressure from the #2 pump, the main relief seems to be set too high, 5500psi at end of bucket dump. I went back through the previous thread and need to check pressure on the other movements along with spool cap pressure from the RCV's and list those. This machine has some contamination in the fluid. Every time I open a line or valve, I get small bits of what looks like algae or mold, similar to what would be found in diesel fuel thats had water in it. I've changed fluid once along with all the filters, but may be doing it again soon. I saw the displayed pressures, but wanted to verify with gauges what I was seeing. Thanks again, your help is much appreciated.
Good day A point that you are maybe aware, at the display you have a weight lifter symbol, this will show up for ten seconds or so when you activate the button on the lever increasing the working pressure 5000 psi. plus or minus fifty. Kind regards Uffex
I made up a spread sheet to start tracking what I've done and to note pressures, etc. Here's what I have so far. The pump pressures were check while moving arm out/boom up simultaneously. Everything else was check at the end of the stroke and held while trying to get an average number. Bucket curl and swing left are the lowest. The bucket was in the dirt during the swing test. While I had the bucket dug in, I tried to curl the bucket and got a best pressure of 3950. That pressure is up from a previous test with the only change being that I swapped the curl and dump PRV's. Where the machine is at is very muddy right now from recent rain, so I didnt pin the tracks and check them. I still have a lazy right track in Fwd only. In Reverse, the right track goes fine. I can handle that for now, but I need to be able to dig. Component RCV pressure Pressure Adjusted Prop Valve mV F G H Pump #1 4850 Boost 5050 130 138 145 Pump #2 4850 Boost 5050 110 118 130 Servo pump 510 565 Prop Valve #1 Idle 250 Prop Valve #2 Idle 255 Bucket Curl 542 4073 680 Bucket Dump 543 4997 680 Boom down 553 pump #2 4630/ boost both pumps 4880 Boom up 563 4830/4830 Arm in 563 4844/4844 671 Arm out 570 4858/4858 670 Track right Track left Thumb open Thumb close Swing Left 563 2850 Swing Right 564 4601 Shear 563 718
Nice well done I will take a look at those results and come back. Kind regards Uffex
Good day This machine has a lot of problems see attached. Kind regards Uffex
Uffex, Thank you for the information you provided, and the response. I purchased this machine from auction in December. When I loaded/unloaded it I had a hydraulic fail code. I swapped out the car fog light relays for original type, correctly rated, relays. I also found the P1 sensor, on the pump, to be bad, someone had hit it and broke the plastic part of it. The sensor seemed to fix the issue. I changed the oil in the slew motor, it was more water than oil. That could be part of my issue with the slew. For the hydraulics, there was a lot of water in the oil. I changed all the filters, cleaned out the tank, drained what I could from various circuits, and went back with AW68 oil. The oil is still milky looking but nothing like before. I believe the machine holds about 80 gal, and only 45 of that is in the tank. I figure it will take several changes to get it to where its clean. When I pulled the filter access plates off the top of the tank, the large o-rings didn't look the best and I'm guessing had never been replaced. I believe that is the source of the water contamination. Those have been replaced now and I add oil through the port on the top of the return filter plate. The machine could have been partially flooded, but I've not seen any evidence of that in the cab or other areas. For the bucket issue, I've swapped the Port relief valves top to bottom. The result was that the pressure came up from 3500 to 4000, so I still have an issue. I noticed when curling the bucket, it travels 3/4 of the movement then slows way down like a sequence valve is slowing and stopping its movement. I would think the bucket would curl all the way to its full stroke in the same manner as it goes to full stroke in dump. I believe the regeneration valve is my next item to check? I still want to check the line signal pressure from the RCV's to the spool caps as mentioned by FwF. The servo pressure was low, but I've adjusted it to within specs and seem to have good pressure in that system in all circuits. But I still need to check the travel system. I'll look into the slew system, specifically the relief valves on the motor. One of the reasons I quickly jumped to the #2 pump regulator in a previous thread was because of the water in the system. I've seen some small spots of corrosion on other parts and thought I might have had a stuck spool or sleeve. This could be an issue with the slew relief valves as well. I've read through the hydrualic service manuals several times and I'm starting to develop a decent understanding of the system. But I prefer to not pull every piece apart if its not needed, so any and all help is appreciated.
Good day Dhutch 1/ The slew “motor” I guess you mean the transmission. Water in the lube suggests a negligent service guy introducing water in top up or a change. Unless the transmission is making a noise when you operate, the slew suggests that you have made what appropriate action that is necessary. If the fault is with the pressures that would not be affected by the transmission lube. You can disconnect the brake release line (Small lines to the block of the side) to test pressures. 2/ Water in the fluid , I have been involved with this problem on a couple of occasionsWater in the fluid, I have been involved with this problem on a couple of occasions. The method used was as follows. Bucket & arm cylinder had the negative line disconnected at the boom base plumbed into a empty fifty gallon drum. With the equipment raised enough to allow the bucket to roll and the engine dead, loosen the positive line allowing air to enter the line and allow the cylinder to extend, once the cylinder was at full travel disconnect and plug the line from the main valve allow the cyl;inder line to remain open draining to the drum. Start the machine use the equipment to force the cylinder to extend the reaming stroke. Boom cylinders fully raise the boom, rest the bucket on a temporary spoil heap, disconnect the negative line and connect the positive line to the drum. Plug both lines to the main valve, drag the machine from the spoil heap, allowing the cylinders to fully drain into the drum. Oil cooler disconnect and flush with solvent, same procedure with the tank . With the cooler disconnected most of the fluid should drain from the main valve block. Track motors disconnect at the motors and allow to drain. Much of the procedure you will have to adapt according to your circumstances, from the posts infer that the machine has been for a swim. Bucket circuit changing the port relief has only partially resolved the pressure issue. I would endorse your suggested actions. When you pull the spool, be sure to get rid of the residual pressure. If you rap the spool with canvas backed emery paper, abrasive side away from the spool nipping the spool in a vice. This will grip the spool allowing you to loosen the end plug and access the regeneration valve. The corrosion can often occur damage of the water in the fluid. Normally when the fluid is under pressure, erosion will happen to those expensive parts. I suggest making the water issue a priority, if you can hire a filter cart to fill the machine take an oil sample for assurance. Kind regards Uffex
I finally got a chance to work on the 210. I didn't have much time so decided to look at the bucket curl circuit first. Attached is a picture of the metal I found inside the spool valve. Some of the edges of the valve were a little rough, so I polished this with some oil coated 2500 grit sandpaper. I cleaned it up and reinstalled. I pulled the bucket regeneration valve and went through it. I didn't notice anything out of the norm with the internal pieces, however, the small orifice at the inlet port was stopped up with trash that only high pressure shop air would get out. Once it was all cleaned I reassembled it and reinstalled. Before today I was getting about 4000 psi on the pump sensor for bucket curl, now I'm getting 4870ish psi when fully curled and held against the relief. The machine digs like it should. Now I just need to look into the right fwd track and left slew circuits.