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623B Hydraulic Issues

Discussion in 'Scrapers' started by Thomas Martin, Jul 25, 2018.

  1. Thomas Martin

    Thomas Martin Member

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    Been trying to get signed up on the board for a bit with out success but finally got it accomplished today! We are building a 20 acre lake ourselves and bought a couple 623B's and a 65D Challenger with an 18 yard CEPCO pan to move dirt with. Had a multitude of hyd hose issues on the 623's at the start, finally just replaced most every hose in and around the neck area and started to get some up time. One of the machines SN46P02024 we are having issues with the floor wanting to go back and the elevator chain stalling. We looked at relief valves and most seem to be good, verified the spring pressures in the valves are correct. We got a shop manual when we bought the 623's. The one relief I think could be part of the problem is the one in the control valve/spool valve/the one your levers at the seat connect to. I removed it the other day and the valve as it is referred to in the book, looks like a top like you played with as a kid that you would spin, has some wear on it, fairly distinct. I lapped it while was out to try and make it seat better and checked the spring seat pressure. Book calls for around 52 pounds when compressed to 1.39''. My spring had this but someone had previously shimmed it with around .200'' shims. When putting them on the spring and compressing to 1.39'' I was around 90 pounds. Previous owner mentioned floor and other items didn't want to work well after machines got hot so I am guessing someone shimmed the spring trying to gain performance when hot. I think this relief will affect both the elevator and floor. Didn't seem to help any after putting it back together and leaving shims. The floor circuit is making 2500 psi when machine first starts up and the hotter the oil gets the pressure starts dropping and will get down to 1500 psi or some times less. Hyd oil temps are running to high, if it is 90+ outside the oil temp will climb to 180-190. Around 165 degrees pressure starts going down. I have cleaned the radiator and oil cooler. Temps were hitting 200 before cleaning. I have a new relief set up to put in the control valve but not done it yet. My thoughts are the valve in the relief is worn and letting oil past and is causing the relief to open which can super heat the oil as well. We did replace the cartridges in the smaller hyd pump which is what supplies these circuits so we know the pump is good. If we could keep oil temps down in the 160 range things would be pretty good or at least a lot better but I think there are issues somewhere else. The book speaks of 1st forward and 2nd forward speed on the elevator. One speed is all we ever see for forward, I am wondering is we do have the 2 speed if there isn't something wrong in the spool not letting it happen, I can feel a bit of a detent in one spot using the lever but elevator doesn't move. If we should have 2 speed and it isn't whatever is keeping this from happening could be part of the weak elevator chain performance. Sorry for the long 1st post, it has been building up inside me for over a month as I tried to get signed on to the board. I have many other questions but will stop here for now! The other 623 SN is 46P401, it is suppose to be a 1974 model and the other around an 84.
     
  2. mikebramel

    mikebramel Senior Member

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    Flow test
     
  3. d9gdon

    d9gdon Senior Member

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    From the service manual in the torque converter operations section:

    "The pressure reduction valve also gives the operator a method of stopping the oil to the centrifugal valve and converter clutch. The converter is now at minimum capacity. When the converter is at minimum capacity, more engine horsepower is available for the implements because less torque is being sent to the wheels. An air valve is connected to the transmission selection lever in the operators compartment. When the transmission selection lever is moved to the left into the notches in FIRST and SECOND speeds, the air valve is activated. The air valve sends pressure air through opening (30) to the left end of load piston (23). The pressure air causes the load piston to move to the right. The load piston pushes spool (34) to the right. This stops the oil from going to the centrifugal valve and converter clutch. If the selection lever is moved out of the notch, the air to the pressure reduction valve is stopped. The spool will move to the left and oil will again go to the centrifugal valve and converter clutch. When the pressure to the centrifugal valve goes below 300 psi (21.1 kg/cm2), the pressure in chamber (26) and the chamber between slug (24) and spool (34) also goes below 300 psi (21.1 kg/cm2). The force of spring (29) tries to move spool (34) to the left. Poppet valve (31) closes passage (27). The oil in the chamber between slug (24) and spool (34) goes out orifice (25). This action causes a reduction in the speed of the movement of spool (34). When the pressure in chamber (26) and the chamber between slug (24) and spool (34) becomes lower, the valve repeats its operation. This operation keeps a constant pressure going to the centrifugal valve through opening (32)."

    Check to see if that air valve is working correctly to send that extra flow to the elevator motor.

    https://www.heavyequipmentforums.com/threads/623b.72385/
     
  4. Mark250

    Mark250 Senior Member

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    Hi this relief valve is only for bowl, ejector and elevator reverse. the relief for the elevator circuit is in the elevator control valve
    upload_2018-7-26_13-33-45.png
    check that the check valve is ok
    upload_2018-7-26_13-31-51.png
    for second speed the elevator control spool blocks off the drain to the flow control valve check this valve is working ok and that the small hoses are correctly fitted. you can also check the pump cartridge as it is easy to disassemble and check the vanes and cam ring
    upload_2018-7-26_13-41-4.png

    Does the elevator hoses tend to vibrate when the elevator stalls?
    remove the four bolts and hoses from the elevator motor and remove the cartridge check that thhe cam ring is intact and smooth also check the all the small coil springs are intact in the end of the vanes .they break up and can go through thhe system and cause problems .when you pull the hydraulic filters they can be seen caught in the filter and screen.
    Mark
     
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  5. StanRUS

    StanRUS Senior Member

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    If you're using Cat exchange OR motors or cartridges (or Cat classic) check to make sure the rotation is correct for the application.
     
  6. Thomas Martin

    Thomas Martin Member

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    Thanks for the info d9gdon, I have printed your info off and going to study it. The air shift you speak of does work as far as changing the way the torque converter works and changing speed of machine. Can also tell a difference in how the hydraulics perform so I am assuming it is working correctly but I don't have any specific info to say it is.
     
  7. Thomas Martin

    Thomas Martin Member

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    Hoses do not vibrate at all. Not opened up the motor yet to look at that, trying to look at everything leading up to that and see if we find anything wrong. Oil temps getting to high seems to be a big factor. Everything operates pretty much as it should till oil starts getting over 160 degrees then function starts to go away.
     
  8. Thomas Martin

    Thomas Martin Member

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    We bought the pump cartridges from a hydraulic pump shop, never thought about the rotation. We gave them the numbers off the pump and they new what we needed and sent them over. Guess we need to check this. Operation of everything stayed pretty much the same after putting new cartridges in.
     
  9. StanRUS

    StanRUS Senior Member

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    Adjust the external mechanical linkage! Ditto check linkage adjustment for the floor-ejector
    Hydraulic oil temp: 180 to 220 normal operating range.
     
  10. d9gdon

    d9gdon Senior Member

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    You should have two speeds on the elevator. Definitely need to get that fixed as it is probably contributing to your problem if not causing it. Look at what Mark250 pointed out.
     
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  11. StanRUS

    StanRUS Senior Member

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    Mark250 or any experienced scraper mech would start with the obvious issue(s), duh!
    High oil temp: BS, we use 623s in the Mojave desert!
    @OP, place a block under left side router bit to tilt the gooseneck; gives you more elbow room to work.
     
  12. Mark250

    Mark250 Senior Member

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    As Stan said have you checked the cartridge pump direction. it is easy to tell look at the back of the cartridge there are two sets of arrows the cap screws that hold the cartridge together will line up with one of those sets of arrows that is the direction of rotation
    as two pumps are combined for second gear this is important
    Mark
     
  13. Thomas Martin

    Thomas Martin Member

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    The machine we changed the pump on isn't in the shop yet but will check the rotation when we bring it in. I did find last night that the spool for the elevator wasn't moving as far as it is suppose to on the '74 model machine. The lever right behind the cushion neck control, never could figure out what the heck it was supposed to actually do, seemed to just be in the way, it would move around when moving cushion neck lever and also the elevator lever. Long story short I figured out the elevator lever has the stud/pin on it that is supposed to be in the track/channel of the mystery lever. Finally got everything back in its place and have full spool travel now. Wasn't able to check operation last night, have an upper idler pulley on elevator with bearing out and its removed. Cat house is suppose to have the parts this morning to fix the idler.
     
  14. Thomas Martin

    Thomas Martin Member

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    If we find rotation is wrong does this mean get a different cartridge with correct rotation or is this something you can change?
     
  15. Thomas Martin

    Thomas Martin Member

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    Thanks for the idea of throwing a block under the bit, never thought about doing it that way, had considered driving the front tire up on a block. Never crossed my mind to do what you say.
     
  16. Mark250

    Mark250 Senior Member

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    it is easy to change rotation. we can run you through it if you need to
    Mark
     
  17. Thomas Martin

    Thomas Martin Member

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    Trying to figure out if my pilot hoses are connected correctly on the scraper control valve. There are 3 lines coming off the scraper control valve, 2 on the top at rear of valve and one off the side at the rear. I can't tell for sure by looking at the colored pictures Mark250 posted but looking in our service manual it looks like the line off the side of the scraper control valve should go to the relief valve/flow control valve for the large pump. If this is correct we have a hose wrong. The hose coming off the side of the scraper control valve on our machine is connected to the flow control for the small pump, the hose off the top of the scraper control valve that is closest to the fender is going to tank. I feel like I have found an issue but the diagrams and pictures aren't good enough for me to be confident in what I think I see.
     
  18. Nige

    Nige Senior Member

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    You may well be correct, but a word of caution. If one end is connected a different way to the illustrations there is always a chance that the other end might also be connected different and you are in a situation of "two wrongs making a right".

    Take a couple of good photos of your actual pilot line installation and post them up. Someone will jump in and say whether they are correct or not. Don't fall into the trap of trying to take the photos too close, because it loses context, especially in the case of hydraulic connections.
     
  19. StanRUS

    StanRUS Senior Member

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    Look at the part's book illustrations: The hose going to the hydraulic tank 1st goes to a junction block mounted on the inner side of the fuel tank. That hose hooks to the rear fitting (towards the scrape can) on the control valve.
    Couple of photos would help!
     
  20. Thomas Martin

    Thomas Martin Member

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    Scraper Pic # 1.jpg Scraper Pic # 2.jpg Scraper Pic # 3.jpg Scraper Pic # 4.jpg Hopefully these pictures can let you see what I got.