I have a Grove RT-60#. The pneumatic swivel was leaking air and we took it off. This is what we found. It is badly rusted and pitted around the pneumatic parts. Grove dealer has a replacement for $2,400. I am wondering what sort of thing could I do to get back in business economically? Stranded in Chicago
Hey, Just a thought take it to a machine shop and see if they could bore it and put a sleeve in it, cheaper than $2400 I would think, let us know what you come up with
Get it honed out oversize, grind, chrome, regrind the spindle to fit. Any decent cylinder repair shop should be able to handle it, or refer you.
Lantraxco, I do not understand, if I hone out the outer part oversize, then the inner (aluminum) part of the swivel has to get bigger, bigger diameter? How can I accomplish that? The ID of the swivel is 3.75". It is pretty thick like 5/8 to 3/4" thick. I found a DOM tube for sale by foot at speedy metals with the same exact ID of 3 3/4". The only difference is that it is only 3/8" thick. I think that it is plenty. DOM tubing is nice and smooth inside. I can drill it and weld pipe fittings to it myself, not a problem. Makes sense?
My old boss went through this, he had 4 groves that his dad and him bought new in 73-74 . He said they tried honing, re chroming, etc, never could get some to hold the air, esp in cold weather. My 300 has never leaked air, but my 200's both leaked. Old (70-80's) link belts use a 2 line brass swivel air system. Its like a 3/4" dia, tube within a tube 30" (approx) long. with a swivel top. I inserted it up the center where the wiring goes up through the swivel and mounted it to the top and eliminated the air portion of the factory swivel. The hydraulics are still factory and have never given me a problem. If I remember it was around $70 from link belt. It fits in the tube that the wiring is in, with the wiring. Its a tight fit.
Crane op, I am thinking, can I simply make a new one myself? I can buy a smooth steel tube 3 3/4" ID, drill holes for hydraulic and air lines, and weld pipe fittings to the holes? That's all I need to do, right?
I don't think I would. You are thinking to reuse your old lower half and just rebuild the upper. I think that's a pretty tight tolerance on the seal rings, its 2500psi on the hydro systems, and its stinks when you get crossover going on in the hydro system swivel. The air side is only 120psi, but its the moisture in the air that kills that. Especially in cold weather b/c the moisture in the air system freezes, and rolls the lips of the seals when you turn. Also that's why you've got all the corrosion there, but not in the hydro side. Also you'd have to be right on the money drilling your holes for vertical height, to be sure to be between the sections. Also you'd have to hone/ rebore after drilling to make sure you don't have any intrusion to catch the new seals going back together. Its a 6-8 port swivel isn't it? On the other hand, the new swivel isn't being dropped from the sky, fabbed by machinist fairies, someone is making it. They just have the exact specs. I replaced my air side, with the link belt version, because it was relatively quick and easy, and it works. You can't get any machine work done for $80. In fact if a new swivel complete (both halves) from grove is $2400 with seals ready to bolt up, I don't know that you'd beat that by much by the time you bought seals, machine work and all the labor. If you can do the machine work yourself thats a different cost. If you do rebuild the swivel yourself, take extra time with reassembly, its really easy to nick a seal going back together. I tried to drop one back together with it in the crane, standing on my head. After the 3rd time back together and it still bypassing, I pulled the whole thing out and onto the bench for reassembly.
Ichudov, you have a jig bore don't you (at least if your the same guy from PM)? Then you should have a machine capable of holding tolerance. Although I'm not familiar with the features other than what I can see from the picture. I wouldn't mess with changing the dimensions to suit the stock.
Crane op, I only took off the upper part, I kept the aluminum parts on the crane and the lower part is completely all on the crane.
I'm sure if you read the book, it says all new seals on reassembly. The problem is its seals & backup rings all the way up and down that can, and the new seals won't have that "set" that the old ones have had from being stuck in there since 1978. So when you go back together, you have to fight to keep those all tucked in and started right, and that's not a great place to work in the turrent. If I was resealing and trying to drop it in, in the crane, I think a chain fall to slowly drop the can with a helper might help, but your just at the wrong angle with it mounted, to start the seals into the can. When you stand there and look at it, you think "man that's a bunch of work to pull all those lines off the bottom, and pull it out, I'll just drop this back on it from up here". But it really ends up easier to just take it out. That would be my recomendation, just to pull it all out, reseal and reinstall, provided you figure out how you're fixing the can. I guess I will admit, the last one when I had troubles dropping it in, it was about 20deg outside. I was cold, the seals were cold, and the can was cold. The shop was warm but no way were the two meeting (boom was 30' in the air for access, no swivel means no hydro). I tried heating/warming the seals and the can, but it never did work until I just gave up and pulled it all out onto the bench.
http://www.chromecraftreman.com/ These guys specialize in that exact kind of repair. Greyson
Pull both parts off the machine. Get a complete set of new seals for every groove in the swivel and take the whole lot to a competent machine shop or hydraulic cylinder repair shop. They will be able to bore out the bad part down below and make a sleeve to put in it or metal spray it to restore the diameter back to the original size. At the moment of course you don't know what that size is because the existing swivel housing is so worn. However with the new seals in their hands the machine shop should be able to figure out what the inside diameter should be. Even though you don't include a photo of the inner spindle I'm pretty sure that will also be worn and will probably need either metal spraying or chroming (a lot depends on what surface is on it now) to bring it back to size. Note: before you go through all that process get a quotation for the work. Even though a new unit is $2400 the services of a machine shop at $150/hour could easily eat that up pretty quickly.
Depending on how much you value your labor/reliability/life expectancy... You could polish up that rust and put new seals in it. The sealing surface is the part that matters, most of that rust and pitting isn't on the sealing surface and won't affect the seals once it's back together.
Yes, I have a set of brand new seals from Grove. New seals definitely going in. I have found out that my hydraulics service place can procure a polished honed tube with exact same ID. I can drill it and weld on the pipe fittings. That might last another 40 years.
When you weld the fittings on, you WILL warp the tube no matter what you do. If you can get a tube somewhat undersize then they can hone it out to finished ID after it's all drilled and welded up. On the other hand you might get lucky, I've been wrong before....
That's what we would do as well . Probably run in the 3 to $500.00 range at my local machine shop .
There might even be a speedi sleeve available in that diameter. I've never used or seen them used for an internal diameter, but if you could use that for the air side it should be as good as any other. I wouldn't want to mess with the hydraulic side of the swivel though.
Lantraxco, I will try to TIG weld it for minimal heat input, many small welds on each nipple, spaced out in time.
OK, an update. We made a replacement swivel outer sleeve. Bought a round piece, drilled holes exactly where we were supposed to, welded nuts on outside etc. Then I took it to be re-honed again. Put in place of the old swivel, not without trouble due to teflon seals stretching, but we managed. The crane now works great. A few more minor leaks but nothing serious.