Grove TMS 250A Boom Removal

[maxlean]

I have a '78 Grove TMS 250A with a leaking telescope cylinder and I need to remove the boom sections to replace the seals. I have the parts manual but the diagram is limited and I am worried about the cable extension and retraction system for the fly section. Does anyone have any experience with this? Anyone with a service manual?

Here is a scan of the boom assembly.

 

[willie59]

I haven't pulled the boom on one of these, but plenty of other booms. On some booms, you can pull the cyl out the back without boom removal, but I think you have to pull the boom on that one. You'll pull the mid and the fly together. Disconnect your extend cables #8 on each side, disconnect the retract cable #9, remove the outer main boom wear pads #47, and I think you have to remove the side wear pads #26, seems like they'll hang something if you don't. I can't tell what #36, 37, & 61 is on the end of main boom??? Disconnect cylinder pin at the area of #6, 35, & 52, you're ready to pull them out. Just pull on the extend/retract cables as your pulling the sections, they'll just slide out along with the boom assy.

 

[td25c]

I wish I could be some help maxlean,But I have never woked on the grove tms 250.My tm 250 is a 1969 model and the boom is totaly different from your tms 250.You have one telescoping cylinder on the first section and the fly section comes out via cables & pullys on the boom at the same time like a fork lift.My grove tm 250 has the two cylinders ,one for each boom section.Now I can remove my cylinders for repair from the rear of the boom and replace the wear pads without taking the boom apart.You might be able to do the same.Mabe another member on the forum has some experience with the grove tms 250 boom.Good luck with the repair and I will be watching and learning on the sideline so keep us posted.You might also try Grove's website for more detailed diagrams.

 

[willie59]

.Now I can remove my cylinders for repair from the rear of the boom and replace the were pads without taking the boom apart.

I was hoping he could do that as well 25c, I'm thinking this one has to come apart though. You can't tell by the parts page how the cyl attaches to the mid section, this is something you have to be able to disconnect to pull out the rear. Also can't tell what kind of support is on the opposite end of the cyl. Many times that support assy won't come out the back of the main boom because it will hit the sheave for the retract cable. I hope he tears into it though so we can see it's innards. The last Grove boom I took apart was an MZ66A manlift, a little different, but similar in many respects.

 

[td25c]

ACCOEQUIP,To my knowledge The grove tms 250 is the only crane that grove made that used the cable & sheave system on the second movable boom section.On the grove tms 300 they stayed whith the two separate cylinders on the movable sections and also had a "dead" section like my tm 250.It woud be handy if the cylinder on the tms 250 would come out the rear of the boom,but from the way you are describing it it sounds like it all has to come apart.

 

[willie59]

It woud be handy if the cylinder on the tms 250 would come out the rear of the boom,but from the way you are describing it it sounds like it all has to come apart.

I agree totally. And if I was Max, I would study it real close to see if it would. And I can't tell by the pics how the cyl attaches to the mid. It's usually a hockey puck on each side of the gland there has to be a way to access them. I looked at pics of this model at machinery trader and I don't see any holes in the side of the boom to access. I've worked on a National boom once that had lock plates you could access from the rear, remove the lock plates, and the cyl would come out. Just can't tell by the parts diagram on this one. And there will be some kind of cyl support at the opposite end of the cylinder.

 

[crane operator]

I've helped do one of these before, and am scratching my head remembering how we did it. If I remember correctly we left the base section in the crane. Then removed the hoses and the bolt blocks from the telescope cylinder, while putting blocks under the cylinder to keep it stable while we removed the other two sections with the cylinder in them. Hose caps save a big mess at that stage (you still have a small mess). We counted exposed threads on the extension and retraction cables tensioner bolts, so that on re-assembly we would be in the right ballpark. We used a forklift and attached to the jib points to drag out the sections, then "caught" them with a second crane to place them on a trailer. The top wear plates have to come out. The side ones get backed off, and I can't remember on the bottom ones. I remember getting the bolts back in the base of the cyl to the base section was a trick. Large pry bar and port-a power. The cyl. can't come out the rear of the boom, b/c the cyl supports are all welded in the middle of the base section. On the cables I think we wired them to the pulleys after removing the nuts from the tensioner bolt. Hope that helps a little. Somehow the rest is forgotten.

 

[maxlean]

Thanks Guys! The removal process is getting a little clearer now.

Atco- From the parts book 61 and 58 are bumper blocks that prevent the boom sections from sliding out too far.

25c- I've got a '72 TD180 neck breaker that is similar to your TM. Those old Groves are great.

Crane Operator- Removal of nuts 31 from the extension cable 8 is a no problem but I am not sure how to remove bolts 31 from retraction cable 9. They are not visible when the boom is retracted. Any hints?

 

[willie59]

Atco- From the parts book 61 and 58 are bumper blocks that prevent the boom sections from sliding out too far.

Crane Operator- Removal of nuts 31 from the extension cable 8 is a no problem but I am not sure how to remove bolts 31 from retraction cable 9. They are not visible when the boom is retracted. Any hints?

You couldn't tell what 61 is by the drawing. If they're blocks--remove them. Remove all blocks/wear pads at the end of the base section. Something will hang if you don't. :Banghead Don't worry about 58 for now, unless you end up having to pull the fly from the mid. That would be when it's on the ground. As for cable 9, are you saying it's attachment is on the inside of the base section and you can't access it?

 

[crane operator]

Yeah, 61 is little metal blocks bolted to the top of the boom section, they've got to come out (I called them top wear plates, they really aren't wear plates because they don't touch anything, but they are on the outer boom ends by the side and bottom wear plates). It looks like the rest of the pads come out with bolt on cover plates, so they should be easy to get out also. Some newer ones they stay in place in recesses in the boom, not nice when its time for replacing them. Remember that the cable 9 is only on one side of the boom, the left side, not both sides like the upper ones. It will be on a welded square block to the end of the base section. Just count exposed threads before pulling the nuts off.

 

[maxlean]

I started taking apart the boom and look what I found.
Oil was leaking from the broken weld at the base of the cylinder when we retracted the boom.

 

[willie59]

I started taking apart the boom and look what I found.
Oil was leaking from the broken weld at the base of the cylinder when we retracted the boom.

Wow Max, that looks ugly!

Possible guesses: Bad weld, weld doesn't look that bad, but one can't tell. Deflection of cylinder while extended placing a bending stress on weld. Extend/retract cables not adjusted properly causing tip setction to bottom out in mid which would put a pulling stress on cyl to continue bringing in mid. Just a couple of thoughts.

 

[td25c]

That dose not look good maxlean.Get us some more pics of the cylinder if you can.That is not normal on a grove.

 

[maxlean]

The weld is at the base of the piston at the pivot end of the main boom just forward of the holding valve and hose connections. In the previous post I mistakenly referred to it as the cylinder.

 

[willie59]

The weld is at the base of the piston at the pivot end of the main boom just forward of the holding valve and hose connections. In the previous post I mistakenly referred to it as the cylinder.

I knew by looking at the pic where the weld is. And I must say, I've never seen that happen on a crane telescope cylinder before. I don't think that's going to be a cheap repair either. That telescope cylinder is a double wall cylinder rod. It has two tubes inside of it to distribute oil to either side of the piston. That seperation at the weld could have damaged the connection of the tubes. By the way, wherebouts you at in Cinci? I'd love to have some ribs from Montgomery Inn, or from Walt's Hitchin' Post over in Northern Kentucky, if they're still there.

 

[maxlean]

Atco- I have stared at the parts diagram of the telescope cylinder and I can't figure out the oil flow path. How does it work?

The crane has been working well it just leaks a few gallons of hyd oil every time I telescope in.

Is grinding out the weld, beveling the outer tube and re-welding not an option?

I live by the Blue Ash Airport not far from The Montgomery Inn.

 

[willie59]

Atco- I have stared at the parts diagram of the telescope cylinder and I can't figure out the oil flow path. How does it work?

The crane has been working well it just leaks a few gallons of hyd oil every time I telescope in.

Is grinding out the weld, beveling the outer tube and re-welding not an option?

I live by the Blue Ash Airport not far from The Montgomery Inn.

"...not far from The Montgomery Inn." Darn it! :Banghead One of these days...I'm going to cross the Brent Spence Bridge...again.

How does it work? Well, I hope I can describe this.

All double acting cylinders have two oil chambers on each side of the piston inside the cylinder. One would be the cylinder barrel side, the other would be the rod side. To make the cylinder move in and out, it requires applying oil to either side of the piston. Most cylinders have fitting connections on the barrel to apply this oil to either side, your cylinder does not have this, because the barrel moves out with the mid section and the rod eye is pinned off and stationary. This makes the rod the stationary component and the barrel the moving component. So how do you get oil to either side of the piston with no connections to the barrel? Double wall cylinder rod. The rod is hollow, and there is a hole drilled in the rod where the piston is attached to the rod inside the cylinder. You just pump oil in this hollow rod, it comes out of the hole on the rod side of the piston, and this would make the cylinder retract. Now, how do we extend the cylinder? There is a tube in the very center of the hollow rod that creates a seperate passage from the hollow portion of the rod. This tube is welded to the rod eye block (where your holding valves are), it extends the length of the hollow rod, and is welded at the very end of the rod, on the barrel side of the piston. This makes an oil delivery path to supply oil to the barrel side of the piston.

To repair it? Like I said, I've never seen this happen before, so I'm a little in the dark on this one. Let's assume this; if you can telescope it in and out, that would suggest the welds on the inner tube are OK. Because if the inner tube was seperated at it's welds, well, the cylinder wouldn't operate properly. As for re-welding it? Honestly, I don't think I would attempt it. In this case, I would have a cylinder shop do this one. I want it done right. And I want it done right the first time. It will probably cost a few buck though. But that's what I would do. Just my humble opinion.

 

[td25c]

I understand it now.That was a good desciption of It ATCOEQUIP.The cyinder is in backwards as compared to most cranes, with the cylinder barrel moving with the boom section insted of the rod.I guess they don it like that because of limited room inside the boom section with the cable & sheave system and dident want any hydraulic lines or fittings inside the boom.If a shop cant fix it,then the rod has to be replaced.When a cylinder rod breaks like that it makes me think of misalignment possibly putting the rod in a bind maybe.Dang the bad luck! Keep us posted maxlean,and good luck with the repair.

 

[willie59]

I understand it now.That was a good desciption of It ATCOEQUIP.The cyinder is in backwards as compared to most cranes, with the cylinder barrel moving with the boom section insted of the rod.I guess they don it like that because of limited room inside the boom section with the cable & sheave system and dident want any hydraulic lines or fittings inside the boom.If a shop cant fix it,then the rod has to be replaced.When a cylinder rod breaks like that it makes me think of misalignment possibly putting the rod in a bind maybe.Dang the bad luck! Keep us posted maxlean,and good luck with the repair.

You've got it pretty much figured out 25c. It's the same design the Grove and JLG, as well as others, use on aerial boom lifts. One thing I'm curious about was the extend/retract cable adjustment. The strength of the cylinder in general, and the weld in particular; is pushing/holding the boom extended. It's not designed to take a lot of force pulling the boom in. If the retract cable was not adjusted properly that it caused the tip section to bottom out during boom in, and the mid was still out several inches, I'm thinking this might possibly put increased pulling stress on that weld. Not sure. My head's seeing it both ways right now. Dang, I wish myself would make my mind up! :Banghead

 

[maxlean]

Thanks for the description. So when I pull on the extension lever the oil flows from the hole in the rod (2) in front of the piston pushing the rod inside the barrel and retracting the boom. When I push on the lever the oil flows through a smaller tube, that is welded to the piston and rod eye, past the piston pushing the rod out and extending the boom. Is that about right?

In the picture of the weld failure the inner tube appears to be part of the rod eye. It has a nice fillet at the base and the tube shows tool marks from a lathe. I assume that it is to help square the rod to rod eye when it is welded and that the tube that caries oil to the piston is smaller. Is that close?

What is the procedure for adjusting the extension and retraction cables?