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Thread: Seized piston

  1. #1

    Seized piston

    The shoebox blew a fuse tonight as soon as turned it on.

    I tried moving the crank arm by hand and could not.

    A bit of disassembly later, and I've found the upper piston is locked up tight and I can not get it to budge.

    I've been filling a my 44cf tank, lubing after every +/- 4 hours of run time. I've got about 12-16 hours of time on the compressor.

    Was running fine when I shut down last evening.

  2. #2
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    Take it apart and see if the piston is seized in the aluminum cylinder or if its locked on to one of the plastic tubes. You will have to unscrew the nut on the end of the piston with the piston still in it.

    Tom

  3. #3
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    Ouch - I'm here to report the same thing.

    I can't hand turn it. I've been using the White Lithium grease every 2 hrs as well. (Stopping it manually, lubing the piston rods and restarting)

    I've successfully filled 5ea 68/4500 over the weeks, and bam. Blew a fuse. Ran out bought 3 more, and BAM blew another. Then tried to crank it by hand, and it wont turn. I can get around 1/4" movement using a wrench and turning, but that's it.



    Per the youtube instructions - I can not remove my Upper Cyclinder. I have removed the fittings and soft steel line. Then the C-Clip. The bracket freely spins, with the cyclinder tube as Im trying to pull it out. But it's stuck and not budging. Like it is locked up in the fully extended position. It is like when you degas it and it goes to the home - open position, like it melted there.


    Thanks in advance for any advice.


    Rob

    Editing for PICS!
    HELP!



    Last edited by PB_RoB; 08-16-2010 at 06:36 PM.

  4. #4
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    Ok

    here we go.

    First see the sticky exploded view and ALL the other stickies in this forum.

    UNPLUG the ShoeBox from power supply.


    Do not loosen the 4 bolts holding the air block or the bearing support bracket. [yet]



    1. remove connecting rod #53. Then try and turn the crank shaft. It will turn freely or should.
    If it doesnt STOP and report here.

    2. Unscrew the air line fittings from both cylinders. The outside nut on the fitting. Dont unscrew the fitting from the air block.

    3. Remove the snap ring #10 from both cylinders.

    4. Now push the cylinders to the left to slide them out. They ride on 2 orings and require a SLIGHT amount of pressure to push out.

  5. #5
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    Just saw your edit Rob. Can you remove either cylinder?

  6. #6
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    Quote Originally Posted by ShoeBox Tech
    Just saw your edit Rob. Can you remove either cylinder?

    Yes - and edited again with pic... bottom free no problem.

    output pressure at 85 psi on the feeder compressor with water trap.... by the way.

  7. #7
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    Oh boy.

    Mark the top shaft real good with a sharpie on both sides of the shaft block. We want to put the shaft back in the exact spot it is now.

    Loosen the 2 allen screws on the shaft block for the top cylinder. Unscrew them half way.

    Now pull the cylinder out.

  8. #8
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    Doh...........You will have to remove the spring from the collar also.

  9. #9
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    Quote Originally Posted by ShoeBox Tech
    Oh boy.

    Mark the top shaft real good with a sharpie on both sides of the shaft block. We want to put the shaft back in the exact spot it is now.

    Loosen the 2 allen screws on the shaft block for the top cylinder. Unscrew them half way.

    Now pull the cylinder out.

    I removed the 2 set allen screws as well as the end spacer for the Spring Shutoff. (Marked both very thoroughly first for placement. (Piston Stage 2)

    It still will not budge Cylinder Stage 2 and Piston Stage 2. Will not come out? together?


    Next thing to try?

    .

  10. #10
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    Quote Originally Posted by PB_RoB
    I removed the 2 set allen screws as well as the end spacer for the Spring Shutoff. (Marked both very thoroughly first for placement. (Piston Stage 2)

    It still will not budge Cylinder Stage 2 and Piston Stage 2. Will not come out? together?


    Next thing to try?

    .

    Doh, ya you would have to remove the collar for the spring also.

    Twist it back and forth and PULL. It will come out.

  11. #11
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    Quote Originally Posted by ShoeBox Tech
    Doh, ya you would have to remove the collar for the spring also.

    Twist it back and forth and PULL. It will come out.

    ok - Im getting totally pissed........ ARGHGHGH (Stressing me out)



    It ABSOLUTELY will not pull, or twist out. I used a Nail Set to get it as far as I did. It is stuck in the shaft block.... I have removed all set screws - cylinder 1 and 2. I have tried to remove it with a screw driver and the freaking thing is STUCK HARD...... There is NOTHING holding the Cylinder 2 piston - it should be free floating. I dont get it...... the outer cylinder spins so how to twist it? Do you want me to take Channel locks to it? It will get destroyed... I removed the allens totally out.....

    There is no way it simply slides on and off. ( in and out of the shaft block )



    .
    Last edited by PB_RoB; 08-16-2010 at 07:50 PM.

  12. #12
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    Quote Originally Posted by PB_RoB
    ok - Im getting totally pissed........ ARGHGHGH (Stressing me out)



    It ABSOLUTELY will not pull, or twist out. I used a Nail Set to get it as far as I did. It is stuck in the shaft block.... I have removed all set screws - cylinder 1 and 2. I have tried to remove it with a screw driver and the freaking thing is STUCK HARD...... There is NOTHING holding the Cylinder 2 piston - it should be free floating. I dont get it...... the outer cylinder spins so how to twist it? Do you want me to take Channel locks to it? It will get destroyed... I removed the allens totally out.....

    There is no way it simply slides on and off. ( in and out of the shaft block )



    .

    ok..........PM inbound.

  13. #13
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    What's making me mad, is I know I can totally do this - but I dont want to F' it up. I am very mechanically inclined and I know by the vids - that this should be way easier (looser) that what it is....

    Thanks for the help though, not upset with you at all - just the situation. ( I really appreciate your help though)

    Image so far.... where it's stuck - the last 1/4" or so - I can not hold the shaft block close enough by hand to the Bearing support bracket to be able to use the punch to remove it the last 1/4" It wants to move when I tap it.



    Im done for the night - Im on the East Coast (Florida) and I have to be at work at 4:20am every day from Mon through Fri (13 hr shifts) (up at 3:45am)....

    I will check my PM and that's it, shower and bed for me for tonight.


    .

  14. #14
    I'll try to answer the same questions you've been asking of Rob:

    Part numbers reference your exploded diagram.

    Bottom cylinder is 100% free and moves with slight resistance.

    Top cylinder was locked up tight. I put very significant hand only force and was able to get the upper cylinder to move, but all I wound up doing was to pull part #5 out, but #6/7/11 are stuck inside the upper cylinder.

    The set screws are removed from the shaft block, but I can not get the piston stage 2 (#5) to come free from the shaft block.

    Also between wiping the grease off the piston, and my hands and cleaning the shaft so I could get a grip on things, I've managed to wipe off the marks I put on the piston stage2.

  15. #15
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    Quote Originally Posted by jdonovan
    I'll try to answer the same questions you've been asking of Rob:

    Part numbers reference your exploded diagram.

    Bottom cylinder is 100% free and moves with slight resistance.

    Top cylinder was locked up tight. I put very significant hand only force and was able to get the upper cylinder to move, but all I wound up doing was to pull part #5 out, but #6/7/11 are stuck inside the upper cylinder.

    The set screws are removed from the shaft block, but I can not get the piston stage 2 (#5) to come free from the shaft block.

    Also between wiping the grease off the piston, and my hands and cleaning the shaft so I could get a grip on things, I've managed to wipe off the marks I put on the piston stage2.

    Oh boy again.

    If the set screws are loose the shaft is hanging up on burs left from the set screws.

    Make sure the set screws are unscrewed and twist and pull the shaft out of the shaft block

    Send me the cylinder and shaft and I will send you back a good assembly.

  16. #16
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    Quote Originally Posted by ShoeBox Tech
    Oh boy again.

    If the set screws are loose the shaft is hanging up on burs left from the set screws.

    Make sure the set screws are unscrewed and twist and pull the shaft out of the shaft block

    Send me the cylinder and shaft and I will send you back a good assembly.

    They will be shipping out today 2nd Day Air.

    Also Sorry Jdonovan - for thread jacking...
    I just wanted to keep my post in with yours since I had the exact same problem. However my Piston would not come free from the Shaft block.

    But after talking with Shoebox Tech on the phone, he is going to fix me up....

    @ Shoebox Tech - please keep me informed. I am dieing to know what is locked up in the Cylinder. But yet it can still spin freely around the piston.


    I'm feeling allot better after a nights sleep too.
    Last edited by PB_RoB; 08-17-2010 at 06:42 AM.

  17. #17
    Quote Originally Posted by PB_RoB
    Also Sorry Jdonovan - for thread jacking...
    I just wanted to keep my post in with yours since I had the exact same problem. However my Piston would not come free from the Shaft block.
    No problem, some of the things you described/posted were the EXACT same problems I was having.

  18. #18
    Quote Originally Posted by ShoeBox Tech
    Oh boy again.

    If the set screws are loose the shaft is hanging up on burs left from the set screws.
    Them were some burs.... It felt more like a .001/.002 press-fit part.
    I had to pull the support arm bracket and shaft block and put them into a vice and pound out the piston with a punch/hammer. It was so tight I debated switching to the arbor press. :

    Quote Originally Posted by ShoeBox Tech
    Send me the cylinder and shaft and I will send you back a good assembly.
    The shaft for the lower piston was also bent sightly, so both pistons are headed your way. Makes no sense to fix one, only to have a problem re-appear on the lower.

    They will go out 2-day tomorrow so you should have them before the end of the week.

  19. #19
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    OK - I spoke with Shoebox tech on the phone today....


    Shoebox Tech - Can you confirm if this brand is ok to use?

    This is what I used to lube. Again I did so every 2 hrs with the shaft "fully" extended (open position) and used the amount the size of the head of a Q-tip (pea size) all around near the cylinder.

    Since you said it looked dry, Im wondering if becuase this is "GREEN" ECO grease, maybe it is breaking down quicker than normal. But I did have the oil sludge coming out from around the non-c-clip side of the cylinder as well. (in my other post)

    Anyway - tell me a good brand and I will switch! I dont want to go through this again, Im scared that It'll break again. O_o



    Thanks for the help - I appreciate the phone call and you keeping me on top of it! Great SERVICE! Very Appreciated!

    Rob

  20. #20
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    Quote Originally Posted by PB_RoB
    Shoebox Tech - Can you confirm if this brand is ok to use?

    Rob
    At this point I can not. Look on the back and read ALL the print. Do you see this any where.

    "NLGI Grade 2"

  21. #21
    Success!

    The new pistons dropped right in.

    The shaft upper seems to align quite easily on the bushing.

    < 15 min and I was making high pressure air.

    But yesterday my big shop compressor threw a rod and destroyed the whole pump head.... so it will be a bit of shopping before I'll be doing any extended runs.

    thanks for all of the help in getting this sorted out.

  22. #22
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    Im going to begin running my again this weekend as well. Went back together great!

    Thanks SHOEBOX TECH for the help! I will let you know if it works properly or not!

  23. #23
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    Quote Originally Posted by PB_RoB
    Im going to begin running my again this weekend as well. Went back together great!

    Thanks SHOEBOX TECH for the help! I will let you know if it works properly or not!

    I just wanted to reply so that if anyone was concerned or apprehensive on getting one - don't be.

    I just got through filling 8 tanks over the course of a day and Greasing every 1 1/2 hrs. With no issues what so ever. It works like a champ!

    Thanks Shoebox tech for parts and the help. It's a beautiful thing!


    I just have to get my bleed issue worked out now.


    .
    Last edited by PB_RoB; 09-20-2010 at 01:12 PM.

  24. #24
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    PB,

    PM me your addy and I will send you a new vent rod. It should solve your problems.

    Tom

  25. #25
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    PM'd thanks AGD!

    .

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