Hello out there, has anyone got any experience on a leaking EC25 slew motor. I recently bought a EC25 and there is a leak on the top of the slew motor under the seat. The top of the motor appears to have a recessed cover and this slowly fills with hydraulic oil until it runs down the side of the motor. I have the repair manual but it is not very detailed on the slew motor . There was a rubber ring around the top cover when i got the machine but it had deteriorated due to the oil contact and literally stretched and fell apart in my hands . Any help of guidance here would be greatly appreciated. Thanks Graham Mann
You should post your serial number for a good start.
Gary , Tks for that, Ill get onto it this morning , I managed to get some parts drawings on line and I think it is a case of get the motor off and replace the seals. Ive not done any work with hydraulics before other than replacing seals on a cylinder, the motor strip down is new ground for me, that and getting it out of the machine without too much difficulty.
Serial Number is 28120451
Getting someone with experience to mentor you through the repair is a good idea but not essential if you take photos of every stage of disassembly then use them in reverse order during assembly. Work area cleanliness is a must, the dinner table is good. Worn internals cause the case of the motor to over pressurise so inspect the rotating group slippers and lens plate for wear. A complete tear down usually requires new bearings and seals so expect that. A biggie is ensure the motor is full of oil before running it, parts in them have very fine tolerances and only last seconds if they are dry. No doubt you'll have some trepidation but they aren't really that complicated
Tones, many thanks for the response, well appreciated sir. Cleanliness I understand with hydraulics, its essential. I have an exploded parts diagram but there is nothing referred to as the rotating group slippers or lens plate , here is a link to the parts catalogue , pages 256 & 257. I have ordered the following parts VOE11712930 & VOE11715608. Thanks for the tip re' ensuring the motor is filled with oil before using. I was hoping not to have to change bearings etc, I am assuming that the seals at the top of the motor case have failed, its leaks constantly whether or not the the hydraulics are live, the hydraulic tank is mounted higher than the motor and allowing for wear in the motor the case will be pressurised by the tank being higher, well with my limited experience (none) I am assuming that that is the case. The excavator has 3500 hrs total on it.
I can't find a parts manual so I'll keep it as general as possible. The leaking seal maybe a symptom of a failure of an internal part in the motor. Tank pressure shouldn't have caused this hence the need to look for the cause IMHO. More often than not manuals never show the internals of the slew or drive motors because they sell them complete. Very few equipment manufacturers make these parts so finding out who does will lead you a manual. It could be Rexroth, Danfoss or a host of others. You maybe lucky enough to find a tag on the motor with that info on the motor. I don't wish to seem be doom and gloom,just trying to keep it real and pass on my past experiences.
Tones thanks again, I guess when I get the motor out of the excavator I will have a much better idea when I have it opened up. In you experience is it possible to test the motor prior to installing it back into the excavator, when I say test I mean leak test to gauge how worn the unit is and obviously to test shaft seals etc.
The only test I know of is to test the amount of casedrain flow assuming it has a casedrain. To do this the motor has to be on the machine. Remove the hose near the tank and place it in a pail, then jam the machine bucket so it can't move, with the engine at wide open throttle hold the slew control to the max for 1min then stop. Measure the amount of oil in the pail. For a motor that size there should be a litre or 2, anymore that this is a fair indication that there's internal leakage which comes back to something not right with the rotating group like a scratched lens plate or more. If there's 3 hoses on the motor 1 of them is the casedrain usually on the side and smaller that the other 2. If there isn't a casedrain then others here maybe able to assist as I have no experience to pass on. Good hydraulic shops usually have test facilities and ability to test for external leaks but they may want to do the repair and with a bit of negotiation become your mentor. That's were I got my little bit of knowledge from.
Hi, did you ever get this resolved? I have the same issue at the moment.
Yes I got it resolved, I had to remove the motor to work on it which was not too difficult, 6 bolts (I think) to remove and the motor lifts straight out, the hoses are a bit of a pain as there was not a lot of room. My leak was from around the brake piston which is pretty much the full diameter of the motor. The most difficult part was the removal of the bellville /spring washer. I had to make up some tools to be able to compress it in order to remove the large circlip on top of the Bellville washer/brake piston. The thin plate on the top of the motor is really just a dust cover but if you can avoid damaging it when you remove it you will be able to use it again. I actually put a hole in it with a screwdriver to remove it by levering it up and then I just soldered up the hole when I reassembled it, it worked ok . I bought a spares kit for which was expensive ie over £200 but I completed the repairs with stock size 'O' rings from a seal supplier and so far no problems . The O ring groove on the brake piston is not like your normal groove or slot, it has a strange profile for an O ring. I thought when I first saw it that it was some kind of special seal that should go there but its just an O ring , well thats what came with the repair kit which is still on my desk. Getting the brake piston back in with the o ring in position is not easy and I shaved some of the O ring off on the sharp machined edges as I was pushing it back in, it still sealed ok and the O ring that had been leaking had suffered the same problem, sections of it had been shaved off. The biggest problem is removing the bellville washer / spring. You have to make a sleeve as big as you can to get as close to the edge of the bellville washer as you can whilst still allowing enough room to remove the large circlip, when you take the motor out you will see what i mean. I used the threaded hole in the middle of the brake piston to compress the bellville washer using a threaded bar but I felt that the load on it was going to damage the thread in the brake piston. If I had to do it again I would make a better tool to compress the belville washer. I would suggest that you make a tool that allows you to remove the circlip easily, its very tempting to just knock the circlip out but if your tool is not up to the job you will get it apart and then you wont get it back together. Its a pain getting it all aligned up and level and then messing with the circlip. I have some photos etc that I can let you have, I have machine tooling at home that allows me to make up bespoke tools and if you dont have that capability I would suggest that you remove the motor and put it into a shop for seal changing . Hope that helps and I can send you the photos if you let me have an email address. The spares kit was easily sourced but expensive for what I received.
Thanks for that info that is a great help. Yes pictures would be great to see what I’m up against. I’ll send you on my email for the pics.