OT?-Friction Crane Boom Not Lowering
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  1. #1
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    Default OT?-Friction Crane Boom Not Lowering

    Been working on my 40ton P&H, finally got it in front of the shop, been changing a bunch of hoses on the control system. Bled the system yesterday, fired it up and wanted to start putting the boom back on it.

    When I took the boom off to move it, I could only boom up, it wouldn't boom down with only the boom heel. It did this when I first got it, the boom heel alone wasnt enough weight to pull it down. I hung the hook block on the end of the heel and that did it.

    Tried that trick again, and it didn't help. I hung all the fast line balls on the heel as well, same thing, no boom down.

    The brake is releasing correctly, I can wiggle it by hand when it's released. And the boom drum twitches slightly when I try to boom down, but dosen't move. Boom dog is released as well.

    Anyone have any ideas before I start adding more weight to it?

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  3. #2
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    That uses cable and pulleys to raise and lower right? Is there rust or some other problem with the pulleys that the winch can overcome but gravity can not?

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    Quote Originally Posted by Rob F. View Post
    That uses cable and pulleys to raise and lower right? Is there rust or some other problem with the pulleys that the winch can overcome but gravity can not?
    Cables operate everything, with clutches and brakes controlling the winches, which in turn are controlled by master and slave cylinders.

    The boom cable is in rough shape, once I got the boom attached and on the ground, I was planning on restringing it with new cable.

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    Cable could be to stiff from dirt/rust, will oil help it? I would use diesel with a little motor oil in it in a pump sprayer and climb up and spray it all. Cables need lube to be happy.
    I was really close to buying a crane similar to your some years ago but couldnt justify the space to use it. Got a little carry deck instead.

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    More weight on the end of the boom section, that's a lot of cable weight and friction to over come.

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    For right now I'm planning to put 60' or 70' of main boom and the 30' jib on it. Park it front of the shop and use it as a yard crane, that boom config would reach pretty much my whole yard. The truck parts works too, but needs tires, air lines, brakes, lots of other little issues fixed, so it'll never go down the road again.

    Eventually, I'll be using this machine to build a larger shop with overhead cranes.

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    Quote Originally Posted by lars66 View Post
    More weight on the end of the boom section, that's a lot of cable weight and friction to over come.
    I've got everything hung from the boom attachment points on the heel. I didn't want to go too crazy with it and possibly damage those attachment points (bend the ears)

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    your machine looks to be rigged with 1/2 in boom cable with 3 upper and 3 lower sheaves ----6 to 1 reduction
    boom base is around 2600 lb

    each cable strand loading is light--400-500 lb
    combination of stiff wire rope, internal spool shaft gumming, possible rust and stiff sheaves likely account for combined frictional holding

    recommend used or new ATF poured on any moving system--lube all zerks
    atf on wire rope---use poly strapping around boom base --add 2000 lbs and
    your boom will likely lower

    I have not owned P+H but did own Marion, Bucyrus and Bay City machines all of which had their issues as cable machines

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    Is there a boom hoist ratchet? Most cranes have them.. Be sure it is not engaged or it will not boom down....I have some experience with "poor and helpless" but mostly American and Lima...Cheers Ramsay 1

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    Quote Originally Posted by ramsay1 View Post
    Is there a boom hoist ratchet? Most cranes have them.. Be sure it is not engaged or it will not boom down....I have some experience with "poor and helpless" but mostly American and Lima...Cheers Ramsay 1
    There is, it is released.

    Sent from my SM-G965U using Tapatalk

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    The hydraulics on those P&H cranes are a problem. BUT, it has been almost 40 years since I had that problem and don't remember the eccentricities. Transmission oil is for transmissions , there is no magic in the red color. I would not hang any more on the heel . That boom is expensive and P&H doesn't build cranes anymore so if you trash it you will be SOL. If you have a power down, try that gently. Be careful, don't break anything.

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    Quote Originally Posted by tdmidget View Post
    If you have a power down
    I do have power down, but as I've understood that, it's only a 1 way bearing in the hoist assembly that only lets it play out line as fast as the engine is turning.

    Meaning I don't have to operate a brake on the boom, just idle the engine and tell it to boom down.

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    Youll probably have to attach a lever hoist to the cable ,and pull it off the drum a bit at a time.If you have a truck with a winch,you can do the same with the truck winch...seeing as the boom cable is to be replaced ,it wont hurt if its kinked by the clips.........Personally,I d hook up a system to lower the boom heel,then cut the cable........I ve dragged up a 70ft boom with two Yale lever hoists......Used to drive a low loader ,and picking up crawler cranes was always a challenge,as the loose wire always wanted to wind up as the crane was moved...One time ,I was lowering a boom,and it suddenly fell down,cable was too short....hauled it back up with the dragline cable .

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    Those "planetary load lowering" boom hoists can be very tricky to keep adjusted and can refuse to lower or can even creep upward

    if either the boom brake or the boom hoist band are a little too tight or sticky .

    Sometimes it takes considerable load on the boom to get it to come down.

    Try adding more load and if that doesn't work you may need to back off brake and clutch band settings

    a little, but always watch that boom for upward creep anytime the works is running.

    Do you have manuals for that machine?

    Private message me and we can have a phone conversation.

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    Quote Originally Posted by petersen View Post
    Those "planetary load lowering" boom hoists can be very tricky to keep adjusted and can refuse to lower or can even creep upward

    if either the boom brake or the boom hoist band are a little too tight or sticky .

    Sometimes it takes considerable load on the boom to get it to come down.

    Try adding more load and if that doesn't work you may need to back off brake and clutch band settings

    a little, but always watch that boom for upward creep anytime the works is running.

    Do you have manuals for that machine?

    Private message me and we can have a phone conversation.
    I haven't adjusted anything on it, very hesitant to do so without know what I'm doing.

    last time I was running it, the swing would keep swinging (even with the swing brake on, the brake it's very effective tbh). The machine was not leveled, so that have been the issue. But I have to adjust a swing clutch.

    PM sent.

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    Quote Originally Posted by alskdjfhg View Post
    I do have power down, but as I've understood that, it's only a 1 way bearing in the hoist assembly that only lets it play out line as fast as the engine is turning.

    Meaning I don't have to operate a brake on the boom, just idle the engine and tell it to boom down.
    It is known as a sprag unit.. Americans use them to lower the boom..On an American with such setup, you can push the boom lever to lower it and lock it and get out of the machine and when the boom rests on the ground, the boom drum will just stop turning....On Americans equipped with a torque converter, there is a device which disengages the sprag unit ONLY when the boom hoist ratchet is engaged so that loads can be lowered against the torque converter for short distances....There should also be a brake on the boom drum that must open to allow the boom to lower.. Maybe the brake is not opening for some reason.. Will it boom up? Ramsay1

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    Quote Originally Posted by ramsay1 View Post
    It is known as a sprag unit.. Americans use them to lower the boom..On an American with such setup, you can push the boom lever to lower it and lock it and get out of the machine and when the boom rests on the ground, the boom drum will just stop turning....On Americans equipped with a torque converter, there is a device which disengages the sprag unit ONLY when the boom hoist ratchet is engaged so that loads can be lowered against the torque converter for short distances....There should also be a brake on the boom drum that must open to allow the boom to lower.. Maybe the brake is not opening for some reason.. Will it boom up? Ramsay1
    It will boom up.

    And the boom hoist brake releases, I can move the brake band by hand when I tell the crane to boom down.

    I'm going to throw another 500 lbs on the boom heel, lube up the cables and sheeves and hopefully that's enough.

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    Quote Originally Posted by alskdjfhg View Post
    It will boom up.

    And the boom hoist brake releases, I can move the brake band by hand when I tell the crane to boom down.

    I'm going to throw another 500 lbs on the boom heel, lube up the cables and sheeves and hopefully that's enough.
    I know this is a dumb question but how many wraps of cable are left on the drum ? When the boom is resting on the ground, there should be about six wraps left on the drum.....It has been a long time since I worked on cranes and a really long time since I was inside of a P&H....Ramsay 1

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    is the cable loose feeding the sheaves or is it tight? my old thing has some clutches that stick some times, the brake is loose but the clutch hasn't totally disengaged. have to rapp on it with a hammer especially after sitting for a few months

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    Quote Originally Posted by alskdjfhg View Post
    It will boom up.

    And the boom hoist brake releases, I can move the brake band by hand when I tell the crane to boom down.

    I'm going to throw another 500 lbs on the boom heel, lube up the cables and sheeves and hopefully that's enough.
    On the subject of the sprag unit, (formsprag), there is special fluid that goes in this unit...Do not use oil, type a, or anything other than the approved fluid or you will find that your boom will drop when you boom down and it will really drop at a rapid pace with a load on it.. You are supposed to flush with kerosene every so often and fill with fresh fluid to the half way point... I remember this from the American cranes I had to maintain and from factory training.. Cheers; Ramsay 1

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