Trying to get hydraulic cylinder apart. Come on man!

Trying to repair a smaller hydro cylinder on a boom lift. This is the "master leveling cylinder" for the basket. It runs at the very back of the machine. I cannot pull the top pin without running the boom to the moon and I am not sure what the basket is going to do. I figured I could just leave the rod and its pin in place and just pull the barrel and do an "in situ" repair.

Well I can't get the damn head off! this is a screw in type where the head screws down in the barrel. I cannot find a friggin set screw but there are 4 pockets in the head for a proper spanner that someone already beat up. So I tried that. That head will not move at all! Never had one stuck like this. I know there is not a grub in the top, but I studied the sides for 30min trying to see if there was a grub in the side. Just cannot find one.

Anyone ever see a cylinder with no retainer on the head? I am hoping I am missing something here.

I've never seen it done, but did they use loctite?

Weld some blocks on and get angered with it. Some of the small guys are tougher than the big guys, you can do it!

Welding a piece on it to knock it with a sledge will also heat it up locally and be a big help in making it come loose. A very common field practice to get them apart. I leave the tab on and retighten them a bit more after its wrench tight before I grind it off.

Remove the entire cylinder to get better access to it, it's too difficult to do that back in the boom hoist cylinder pocket, ain't got enough room to do squat. The platform slave cylinder should have holding valves so it ain't gonna do nothing. If it does, well, then there's another problem you need to fix. Yes I've done a number of cylinders that the gland screws inside the barrel until flush with the end of the barrel, 4 holes in the head for a spanner, no set screw, really not uncommon. Peen the barrel all the way around back to just shy of the retract port fitting, the gland will stop shy of that fitting. Whatever you don't don't heat it with a torch unless you have no other option, unless it's done evenly you'll distort the metal of the cylinder barrel.

Thanks guys. Sounds like I just need to get more western. Sort of surprised if there is not grub screw for a man lift. Not like I have ever seen one unscrew itself though....lol

All I have done so far is a punch and 2lb hammer. Usually they start walking though. Was trying to save the hassle of taking the boom up and fighting with the pin that seems like someone rigged.

Well I am officially 'frustrated' beyond words..... Took the advice to pull the cylinder so I did some plugging and took the boom to the moon so I could get to the pin. It is a 1" pin. Appears someone was in it before and put a little tack weld on the pin. I figured no biggy. A few pops with a chisel and that was off and I figure we were on our way. After an hour of beating on that pin with a sledge, I decided this was going to take some serious effort. So I went back to see if I could get that head out of the cylinder. I chipped all the paint around the top and cannot find a grub screw. So I got more aggressive and got it to turn about 1" or more. Figured I was on my way there. Nope, progress has stopped and the holes in the head are pretty craptastic.

Curious where you guys would go here? I am not sure how hard that cross pin is but a torch is out of the question for cutting it. I thought about a sawzall but will probably roast $500 in blades and once I scratch that pin, I am committed. I need to be very careful with fire right now due to location and oil on everything.

If I could get the pin out, that would be great, but she is froze in good. I cannot heat on the inside due to hydro lines all over. Could add some heat on the outside but I can only do so much as this is a highly structural area for the boom. My concern is mushrooming the pin in the bore and make things even more fun.

How long is the pin? sawzall will cut a pretty hard pin, but you could drill through the center of the pin and weld that right back up, that will heat and shrink the pin the same as torching a hole. Or set up a press and push it out.

I'm not familiar with your machine. Does the cylinder that you are working on have a counter balance valve on it, also known as a holding valve or a oh sh!t valve? If it does then you have pressure inside the cylinder making it hard to remove the gland nut. If that's the case then I would retract everything and then slowly back off the screws for the counter balance valve or slowly loosen the valve and let the oil spray to release the pressure. Hopefully someone has a better way of doing this, but that's the only way I know how to do it.

Paul Council said:

I'm not familiar with your machine. Does the cylinder that you are working on have a counter balance valve on it, also known as a holding valve or a oh sh!t valve? If it does then you have pressure inside the cylinder making it hard to remove the gland nut. If that's the case then I would retract everything and then slowly back off the screws for the counter balance valve or slowly loosen the valve and let the oil spray to release the pressure. Hopefully someone has a better way of doing this, but that's the only way I know how to do it.

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Paul's onto something here, plus I'd bet the packing nut is set in thread locking compound so what did the outlaw jose whales say "when things look bad that's when you have to get mean, I mean plumb mad dog mean". I normally don't go for the smoke ax but unless willie isn't close by to school us both.... the dam thing is broke so get after it and we can all learn from your mistake of taking my advise.

Good luck!

Here are a couple pics guys! Hard to see but the cross pin for this cylinder is up in the boom section. The tube on the actual cylinder is free for days. No issue there. there is reinforced steel on both sides of the boom which is about 3/4" thick I would say.

Also is a pic of the cylinder I am fighting. You will notice there is a little ding at the top of the barrel from someone else. I am not sure if that is an issue or not. You can see that I have removed paint looking for a screw. I cannot find one and that head is getting pretty beat. I have room to work this if it would cooperate but I think we are beyond that.

The hose on the cylinder is just stuck back on as a drain. The cylinder did not want to extend manually so I grabbed it will the excavator and helped it. I did not remove the 90* elbows on the cylinder but it seems to want to make a mess so figured there were no hiding valves. I know for sure this cylinder has been worked on before because the spanner holes in the head were already beat. However, the dust seal on the rod has green paint on it....maybe a pro job where they touched up when done?

Where's that thread where Willie59 teaches us how to hammer peen the barrel to release stuck glands? Priceless.

I vote for liquid wrench. Oxy acetylene liquid wrench.

Well I rode along with Caveman on this one and also did a little peening per Willie's idea. I brought out the BFH and heavy leather gloves. Something was going to die. I now have the gland up with about 3/4" exposed threads. Ran out of light. It looks like we are going to try the 'in situ' idea here. Once I have the head off, I will have to decide if I machine some new spanner holes or what but I am not going to use a punch for this again. I will also test fit and remachine the threads if needed to make this go together.

So far the threads all look good which should indicate no grub screw, and I don't see any loctite either. I am wondering if the barrel is egged or something. It is a fight the whole way.

Drown that thing with good penetrating oil for overnight

Had one not long ago,unscrewed it with a service truck crane pulling a 3 foot pipe wrench tuff all the way.machine shop fixed threads on both,new seals all is good. What’s that old saying If it jams force it if it brakes it needed replacing anyway lol.Glad you got it going your way

willie59 said:

Drown that thing with good penetrating oil for overnight

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Kroil.... so far, best I've ever found.

Good work! My guess is moisture wicked down the threads and formed enough rust to lock it up. A good stiff wire wheel cleaning and it may screw back in freely. Surprised there isn't a holding valve in that cylinder?

At my dealership the starting quote for a cylinder is 2.5 hours. That's remove, teardown and reseal, then reinstall in 2.5... seems pretty ridiculous when you get something like this^^

Muffler Bearing said:

At my dealership the starting quote for a cylinder is 2.5 hours. That's remove, teardown and reseal, then reinstall in 2.5... seems pretty ridiculous when you get something like this^^

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The key word here is "starting"; That is a min charge of $250 ( @ a bill a hour). As an independent wrench just the last time I did a difficult one I got price quote for a "seal kit" from the "dealer" (that I would have got if it was in stock just to keep the brick and mortor place open and save time) of $360. My seal guy had it all for $45.i ended up billing the job for $400.

Look I'm not trying to knock the guys in the shop but the parts mark up is what keeps me so busy.