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Discussion in 'Other Construction/Demolition Equipment' started by 1693TA, Aug 14, 2020.

  1. 1693TA

    1693TA Senior Member

    Joined:
    Feb 28, 2010
    Messages:
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    Occupation:
    FAA Radar Engineer, (Retired)
    Location:
    Farmington IL
    "It's always something" as Gilda Radner used to say, but I'm looking to force failures of this equipment prior to placing it back into service. Better to fail here than out someplace else remote.

    I do hope it's just packings and seals which have been expended rather than something major. This cylinder is heavy as will getting the boom raised and blocked so it can be extracted.

    Just another chapter of the fun never ends I guess.....
     
  2. 1693TA

    1693TA Senior Member

    Joined:
    Feb 28, 2010
    Messages:
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    Occupation:
    FAA Radar Engineer, (Retired)
    Location:
    Farmington IL
    Appears to be the socket the selector relay plugs into citing corrosion. I can make the boom lift but not consistently. The coil connections are corroded in this particular socket and replacements are on order so very well may be an easy repair with a replacement. I did order the four relays, and four sockets along with wire terminations as I don't like landing bare stripped ends. Should see this stuff soon. Now being able to raise the boom hydraulically, it will be much easier and faster to fabricate a weldment to support it elevated while I remove the cylinder for rebuild.
     
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  3. colson04

    colson04 Senior Member

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    949
    Location:
    Delton, Michigan
    You certainly found a way to keep busy when you bought this lift. I have some winter maintanence work to do on my lift as well. Tires will be my first point to address, followed by a dripping valve body in the hydraulics case. Then a general cleaning and degreasing. I am fairly fortunate that my wiring looks to be in pretty much original condition and nobody has been tampering with it. I do have to rebuild one of the steering cylinder pins as previous owner never greased it and it's sloppy.

    Keep up the good work. I've enjoyed following your progress.
     
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  4. OFF

    OFF Senior Member

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    Occupation:
    HD Mechanic/Shop Foreman
    Location:
    Alberta, Canada
    You'll never be bored with an 80F sitting in the yard.
     
    DMiller likes this.
  5. 1693TA

    1693TA Senior Member

    Joined:
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    Occupation:
    FAA Radar Engineer, (Retired)
    Location:
    Farmington IL
    Appreciate the feedback. Haven't been bored with it as of yet..... Most times on the internet one only reads success stories leaving out the particulars of direction, and what achieved the success. Seldom are true gains and setbacks posted. I would rather involve the audience and give them a chance to participate if they wish. Cheap entertainment if nothing else for the reader.

    It's been an enjoyable exercise for me to work with this lift. Having no experience in this type equipment opens up a new chapter to learn something, and I'll be able to make use of the finished product.

    Once this lift is back to dependable status, I'll address some badly needed maintenance issues also. It appears to have been a stranger to a grease gun for a long time as several pivot point bushings are worn. I have a line boring setup and bore welder and if this service is required to true things back up, I can cover that "in house"; but a return to reliable operation is first.

    Thanks,
     
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  6. 1693TA

    1693TA Senior Member

    Joined:
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    Occupation:
    FAA Radar Engineer, (Retired)
    Location:
    Farmington IL
    Looks like the relays and sockets have shipped, so should see them yet this week. Expecting to see the control cable(s) yet this week also.

    Talked to a gent out west whom rebuilds industrial joysticks and I'm going to pull them during the rewire, send them off for testing/evaluation, and given any attention they may require. These actually work, but the drive is "notchy" in feel and operation. I'm electing to replace all the toggle switches in the basket citing age, exposure, and compromised rubber sealing surfaces also.

    Talked to the hydraulic shop yesterday whom has researched the kit to rebuild the lift cylinder(s), and rotary coupler as it's a known potential leak point. Will save some time if they order the rebuild kit(s) as these kits are all inclusive and the hydraulic shop doesn't carry every seal needed in their inventory. I don't actually know if the rotary coupler is leaking or not, but will look when removing the lift cylinder after the boom is supported. The area is such a wet mess from cylinder gland leakage, it will require clean up prior to going any further.

    Also spent some time on the phone talking with a tube bender friend. He is willing to bend a new cage to use for the platform so looks like I'll just cut the existing one free from it's base and replace complete. I've found two vertical tubes rusted through and a couple more crushed/bent so electing to go the best route and replace.

    Many will look at this as a lot of work for an old lift I'm sure. But, for what I'm into it for, and the use I'll obtain from the finished product, it's worth the effort/expense to me.

    I really don't care to erect scaffolding any longer either.....

    Thanks,
     
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  7. 1693TA

    1693TA Senior Member

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    Occupation:
    FAA Radar Engineer, (Retired)
    Location:
    Farmington IL
    "Off"; Figured I'd go ahead and add this to your original drawing and maybe it'll help someone else down the road:

    upload_2020-12-9_6-26-8.jpeg

    Part numbers on the photo are P&B numbers and current. These part numbers are for 12VDC coils only. There are also 24VDC coils available, along with several other variances.
     
    Last edited: Dec 9, 2020
    OFF likes this.
  8. 1693TA

    1693TA Senior Member

    Joined:
    Feb 28, 2010
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    Occupation:
    FAA Radar Engineer, (Retired)
    Location:
    Farmington IL
    Didn't really work with the lift yesterday at all. Still awaiting the relays, sockets, and a couple sections of SOOW cord/cable. I was able to find a set of test sockets and cables I formerly tested for contact "bounce" with these type relays as dirty or pitted contacts readily show up with an oscilloscope. Test equipment can be your friend when used properly for diagnosis. I'm quite certain all four of these relays will be better off retired from service citing physical appearance. You don't dare "file" or clean up the contact points in these things as the service life is exponentially shortened when you do if they're used at near capacity.....

    Also ordered, (via ebay) 1000 pieces of 4:1 adhesive lined shrink tube in black of 5/16", and 3/8" diameter size. This along with a couple boxes of bare fork type terminals to fit both 12AWG, and 16AWG wiring. These will environmentally protect and support my wire terminations at their respective lands which are either terminal strips, or direct mechanical fastners. Far too many years behind me chasing broken wires and faulty/corroded bare terminations to not follow this simple rule.

    More to follow.

    Thanks,
     
  9. 1693TA

    1693TA Senior Member

    Joined:
    Feb 28, 2010
    Messages:
    320
    Occupation:
    FAA Radar Engineer, (Retired)
    Location:
    Farmington IL
    Lost all up and down hydraulic functions to the boom yesterday. Everything else in the unit works. Cannot get the boom to elevate, nor descend either electrically, nor manually via the push buttons on the proportional control valves. It is as if I've lost pilot pressure within this individual valve section as even the effort required to depress the buttons is less than it was. Other functions such as drive, swing, telescope are all normal. It is only this lift section acting up. Here is a hydraulic diagram of the lift circuit:

    upload_2020-12-23_4-57-57.png
    To attempt isolation of this area of the valve, I opened the manual descent valves and am able to jack the boom up with a floor jack, close the valves and the boom remains in position. I cannot however drive it back down with the proportional valves so obviously no oil is flowing.

    I have rebuilt and checked all the solenoid coils and renewed all sealing rings upon reassembly of the mating parts. I suppose I could have cut or nicked a sealing ring someplace putting these two assemblies back together, and the assumption would be they do work in unison, but the challenge continues. The proportional valves look to be serial flow and with sections fore and aft of the lift valve section working correctly, leads me to suspect only this lift valve section is problematic. Due to packaging I cannot gain access to the spool to manually actuate it but I suspect it is not moving from the centered position due to pilot pressure lacking. That is just an assumption however. It would be nice if the proportional valve bank did have a way for manual operation from external input and I suppose they do with the pushbuttons, but a simple lever or manual plunger directly acting on the valve spool would be useful in this scenario. Kinda/Sorta like a tractor loader valve acts directly upon the spool.
     
  10. 1693TA

    1693TA Senior Member

    Joined:
    Feb 28, 2010
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    Occupation:
    FAA Radar Engineer, (Retired)
    Location:
    Farmington IL
    I'm wondering if the high pressure oil filter used in this hydraulic system is a "full flow", or "bypass" system? I installed new "O" rings onto the solenoid poppet valves controlling the elevate and descend functions but they are still not operational. Shown in this hydraulic flow diagram I cannot tell the answer to the question I pose:

    upload_2020-12-26_7-19-9.png

    Starting to wonder if I have have a stuck spool in the main valve, or internal leakage in the "Force Amplifier" section of the valve precluding the main spool from shifting? Drilling down through information provided I'm able to generate a test scheme to break out individual sections and will follow that scenario after ruling out the easier tasks.

    Regardless, the drive, swing, and telescope functions work fine but the boom refuses to lift either through solenoid control, or manual operation of the poppet valves. All the working functions share the same 24gpm rating section of the main hydraulic pump so I'm thinking the problem is isolated to the boom lift valve. Don't know how parts availability will be for this thing yet as the JLG vendor is closed for the holidays and Racine was sold to Bosch back in 1997, and many valves/parts obsoleted.

    Parked the lift outside for a good cold soak and fires right up at 10 degrees Fahrenheit with little effort. Hold the electric choke toggle down, push the start button and engine cranks to life, release choke toggle about 5 seconds later and the engine smooths out nicely.
     
  11. OFF

    OFF Senior Member

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    Occupation:
    HD Mechanic/Shop Foreman
    Location:
    Alberta, Canada
    In the Racine valve manual I attached to post #88, figure #8, at the bottom of the valve section is a label "null adjustment". Find this on your lift valve section. Loosen off the lock nut (1/2" wrench) and screw in the Allen head screw all the way. The function should start to move in one direction. screwing out should start the function moving in the other direction. You can hear a function start long before you can see it move. On a properly working valve, this adjustment should be left at the center point between the starting point of each function. Usually about 3 turns from one to the other.

    If you get no response at all while doing this, you have a broken spring in the flow control part of the pilot section. See figure 9, for the circled part marked "Pressure Compensator" its just a little spring.
     
  12. 1693TA

    1693TA Senior Member

    Joined:
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    Occupation:
    FAA Radar Engineer, (Retired)
    Location:
    Farmington IL
    Thanks and exactly where I was moving to. I changed the sealing rings the other day with no response from the valve at all. Given the problem did not reveal itself till a wire broke free from a solenoid coil and I removed it to facilitate repairs, I was remaining in this area till proven otherwise. The function worked well prior to this happening. I've read the null adjust procedure several times but did not want to go there quite yet.

    When I depress one of the manual operator buttons I can hear a function attempting to operate whether it's up, or down of the boom command. Not a lot, but it is detectable in the engine tone, or note. This is where I was going with internal valve leakage in the "Force Amplifier" section as I don't think there is enough pressure to displace the sliding piston causing action of the push pin to upset the balance of the spool valve causing it to shift position.

    Looks like the bottom section of the valve drops off and just a few "O" rings needed to reseal if that spring needs replaced.

    Is there enough mechanical pressure available through the compression springs to mechanically shift that spool by cranking or loosening the "null" point? Is that push pin which bears upon the spool mechanically attached to anything, or is it hydraulically shifted?

    Thanks for jumping in. Experience is always a great teacher.
     
    Last edited: Dec 26, 2020
  13. OFF

    OFF Senior Member

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    Occupation:
    HD Mechanic/Shop Foreman
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    The null adjustment seems to work on pilot pressure, not mechanical force. If the null adjusting gets zero response, that spring is broken.
     
  14. 1693TA

    1693TA Senior Member

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    Occupation:
    FAA Radar Engineer, (Retired)
    Location:
    Farmington IL
    Thanks a bunch!! Wanted to verify my suspicion(s) before getting off on a wayward path. I'll be out there later today and will give it a try and report back.
     
  15. 1693TA

    1693TA Senior Member

    Joined:
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    Occupation:
    FAA Radar Engineer, (Retired)
    Location:
    Farmington IL
    Don't rightly know quite what to think. Adjusted the null off center and the boom raised immediately. Adjusted the other extreme and boom readily descended. Recentered adjustment for null position to where it is not loading the engine at rest, and now the push buttons work as there are supposed to. Going to rewire, then see if it works electrically also. Almost suspect I had a frozen Spool in the main valve. I have not changed the hydraulic oil, and have no history other than setting for a long time of the original.

    Simple fix so far.
     
  16. OFF

    OFF Senior Member

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    Occupation:
    HD Mechanic/Shop Foreman
    Location:
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    a piece of dirt got in the wrong place when you resealed it. The null adjustment worked it out. You have to work real clean on those valves. :cool:
     
  17. 1693TA

    1693TA Senior Member

    Joined:
    Feb 28, 2010
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    Occupation:
    FAA Radar Engineer, (Retired)
    Location:
    Farmington IL
    Huh????? You aren't insinuating that a workspace consisting of a pulverized into dirt gravel parking lot with a stiff 15mph breeze crossing over a heavily traveled state highway isn't "sterile" in cleanliness are you????? Not having immediate access to "CapPlugs", I went the trouble to stuff a cotton shop towel in the spaces vacated by the solenoid assemblies while I used non clorinated circuit board cleaner to degrease the "bobbins", followed by an isopropyl bath to remove any residue. LOL. Most everything on this machine is a dirty, greasy, and gritty SOB from lack on any kind of maintenance as it's cheaper to dump oil in it than repair the leaks, ( I suppose). There are two hydraulic hoses from the top of the proportial valves leaking at their respective crimp(s) retaining their ends and the oil stream is right down the face and behind the solenoid valve retaining plates saturating the solenoid coils which are open at their front. This will require hose replacement(s) which I have but need to order additional ends for quantity required. Here again is a photo of the solenoid coils in the boom lift section:

    upload_2020-12-27_15-10-53.jpeg

    These have now been properly repaired and operate well. I did not seal them and do not know if they originally were?

    With exception of the auxiliary hydraulic pump, flashing beacon lamp, and back up horn, all functions appear to be operational. I have a plethora of jumper wires installed to complete circuit runs for broken, or compromised wire runs, and several wraps of friction tape to insulate formerly bare copper strands where the insulation has deteriorated, and broken/fallen away.

    Now comfortable with the machine's operational status, and foreseeable future/tenure, I'll get it a good douche bath with the steam cleaner next week to make things more conducive to a nice working atmosphere. Couple of neighborhood kids need a job so going to have them remove the sheet metal enclosing the engine, and radiator surround, then sandblast the machine clean and get it painted. Hopefully with the boom elevation problem solved, I can extract the cylinder and have it rebuilt this next week too:

    upload_2020-12-27_15-16-23.jpeg
    upload_2020-12-27_15-16-57.jpeg

    I need this lift to reinstall a panel taken off my building, (in the upper right of the photo) due to recent high winds. You can see the gantry I'll use to support the boom while I lift the cylinder out with my skid steer:

    upload_2020-12-27_15-18-44.jpeg

    At the ready once the machine is cleaned and painted I have enough SOOW wire in quantity to rewire the machine complete. Also have all new P&B relays, sockets, circuit breakers, main disconnect switch, and several toggle switches to replace originals. So much of the original hardware is fragile from exposure over the years so better to rebuild this way and know what I've got in the end.

    Really appreciate the assist "Off".

    Thanks,
     
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  18. 1693TA

    1693TA Senior Member

    Joined:
    Feb 28, 2010
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    320
    Occupation:
    FAA Radar Engineer, (Retired)
    Location:
    Farmington IL
    You weren't able to ascertain whether the hydraulic filtration routed through the high pressure filter is full flow or bypass type have you?
     
  19. 1693TA

    1693TA Senior Member

    Joined:
    Feb 28, 2010
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    Occupation:
    FAA Radar Engineer, (Retired)
    Location:
    Farmington IL
    Started removing the former owner's decals. The deceased owned the local "Overhead Door Co." franchise for many years:

    upload_2020-12-27_15-42-56.jpeg

    Heat gun and sharpened scraper do pretty well but the coating is very thick with the decal underneath the paint. Steel substrate appears to be pretty straight too.
     
  20. OFF

    OFF Senior Member

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    Occupation:
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    lol, sometimes there's a fine line between honesty and cruelty. But I meant to be honest, not cruel. The thank you is much appreciated.

    The HP filter I believe is full flow. They never gave any trouble at all btw. The coils were not sealed originally. Just wound, coated wire with a piece of white electrical tape wrapped around the outside to hold it all in. I always mounted a terminal strip right beside the valve body to make wiring easier. I did that to every F, G, & H series I worked on. There's a little hole in the valve face when you take off a pilot section that just keeps pissing oil, for ever. A pencil fits that hole, works perfectly.