I have an RT63S that I bought four years ago. It is a great crane for the thirty or forty hours a year we use it. It has been losing ATF out of the transmission/torque converter for a while. We recently realized that ATF is going into the hydraulic reservoir. As the problem got worse recently the transmission pump can't even create enough pressure to keep the crane in gear. One of our mechanics jumped right in and started disconnecting the electrical end and hydraulics to remove the seal. Our first problem is that he didn't raise the boom before tearing it apart. Getting those boom cylinders out of the way is going to be tough. Do any of you have hydraulic swivel seal experience? Assuming our diagnosis is correct, is there some other underlying problem that could have damaged the swivel? Or do they just wear out? The crane came with loads of literature and manuals, but there is nothing that shows much about the hydraulic swivel itself... Thank you! Jake
Using a crane forty hours a year is pretty darn hard on one. Seals do wear out. Most swivels Ive had to rebuild were on cranes that had sat for an extended period of time. I'd start it up and swing it around a few times once a month or so. Also I usually order at least one extra seal for the swivel. I guess I'm not as good as most but it's very hard to get those seals on without damaging them. Its time consuming but resealing a swivel isn't that hard.
Thank you Knepptune. I am glad you responded after reading your helpful posts in other threads. After talking to our local dealer we are reassembling the swivel so the boom can be raised all of the way. As I mentioned my crew got a little too eager with the disassembly. Once the boom is up we can get all of the swivel apart and try to find our problem. Before attacking the swivel we checked the transmission/torque converter pump to verify it is working properly. I also confirmed there isn't a common cooler for the hydraulic fluid and transmission fluid on our crane. At that point it seemed the swivel could be our only culprit. The initial problem was the transmission slipping. We were also losing ATF that wasn't leaking onto the ground. As the problem got worse early this winter the hydraulic reservoir over flowed at one point and our hydraulic fluid was slightly pink in color (not milky, just pinkish) - this led us to believe we are losing ATF into our hydraulic system somewhere. The swivel and seals look great so far, but we haven't been able to completely disassemble it with the boom lowered all of the way. The swivel will wiggle back and forth, but that may be due to loose set screws - we will find out after the boom gets raised and we get it torn back down. Do you have any other input or advice for our project? After this fiasco we will definitely run the crane regularly. We have owned it about five years now. It runs great, so there is no problem exercising it periodically when it isn't in regular service.
RT63 is a pretty old machine so the seals are probably just wore out. I can offer a couple tips. use a come a long for removal and installation of can. Look for grooves or rust pitting, Try to i.d. the grooves and ports for the trans. so you can pay close attention to them. If the inside of the can is bad you can salvage with spray metalizing and machining. To ease in putting on the teflon seals they should be preheated in oil, think french fryer. It will make them expand. I had a pan and basket with a thermometer and would heat up some hyd. oil to about 260f. drop the rings in for a couple minutes then put them on with a seal pick or small screwdriver. Work quickly. When you get ready to lower the can back on the stem preheat the can so its warm, about 90f. Grease it up good with assembly lube. A lot of times the weight of the can alone will make it slide down. Some after machining took some thumping to get back down. Hope this helps. I always hated the wiring swivel part of the project the most.
Thanks for the pointers kat09. Hopefully we will get it torn apart the rest of the way in the next few days.
On the wiring. I wouldn't start without a little book of the numbered stickers. Electrical section at most home improvement stores will have them. Label each wire with care. I had to do one on a job in the wind and rain the other day. Nothing like doing it under a tarp in a rainstorm. Not ideal but they needed the crane. Most of them need some help from a rubber mallet. Grove uses some hard almost cardboard type seals. They are a pain. I'm gonna try the hot oil idea next time.