M610 roto-swivel leak problems at variable drive sheave

[CharlieNH]

I'd like to connect with someone familiar with repair of this internal roto-swivel, as per the service manual pp. 3-16 and 3-17. I just replaced the two large O-rings and the one medium internal O-ring in the copper gland, and after reassembly, which is a real pain, the darn thing still leaks. Pressure from the valve is 400 psi to the swivel, so it's not above spec. The two things I did not replace are the seal in the outer end of the copper gland, since the parts manual says that's serving only as a wiper. (But, if I do replace it, which way should it face? The current one faces out, that is, open side towards the outside of the machine.) I also did not disassemble the internal parts of the rotoswivel itself including the little seal, item 4, in figure 3-77. So I 'm really wondering where these things tend to leak. I was sure I had the right seals causing the leaks, and I suppose there's a chance I damaged them during installation when they have to slide over the large internal retaining ring groove in the outer half of the sheave. The fluid leaks into the splined space that the sheave slides on, and from there into the center of the sheave and onto the belt. Since this whole job was quite time consuming and frustrating, I'd love to get some advice from someone who has done it before. Thanks!

 

[dmacy]

I had a 610 and replaced the Roto Swivel. I tried to rebuild the old one and it leaked so I replaced it and still got oil on the clutch. I found that the variable clutch (roto-swivel) control valve was seeping oil and it was leaking down on the belt. Make sure the swivel valve is the problem and the oil is not coming from some other place. I have my valve (the old one.)( I think I can find it if you want it) for no charge let me know. Take the cover plate off the outside of the machine so you can look at the swivel valve to see if it is really leaking. If you spray gum cutter or carburator cleaner on the belt when it is running it will get you by for a short time. Dave

 

[CharlieNH]

I had a 610 and replaced the Roto Swivel. I tried to rebuild the old one and it leaked so I replaced it and still got oil on the clutch. I found that the variable clutch (roto-swivel) control valve was seeping oil and it was leaking down on the belt. Make sure the swivel valve is the problem and the oil is not coming from some other place. I have my valve (the old one.)( I think I can find it if you want it) for no charge let me know. Take the cover plate off the outside of the machine so you can look at the swivel valve to see if it is really leaking. If you spray gum cutter or carburator cleaner on the belt when it is running it will get you by for a short time. Dave

Thanks for your reply and your offer. I think I have the problem fixed. I'll give a few more details here for anyone that uses this thread in the future. I earlier put in a new hydraulic pump and did not first readjust the pressure setting on the variable speed valve before using. The belt shifted instantly from high to low and back, rather than the 4 second spec in the manual, and I think that this blew one of the seals in the rotoswivel. The first time I replaced the seals, I was still using the beat up brass piston or gland and also might have damaged the new seals in installing by the snap ring groove. It's a very tight fit. I did a more through job the second time, even replacing part of the rotoswivel to be sure I had all bases covered. When I put it all back together it looked like I still had fluid coming out of somewhere, so , like you, I also looked again at the valve and piping, but could find no leak. I then took off the outer half of the sheave (the belt was also disengaged then) and ran it again with high and low pressure and could see no leak. I now think that I had overgreased it earlier when reinstalling and that all I was getting was residual grease being squeezed out and sprayed by centrifugal force. I've washed it all down and hope to confirm that it's all fixed when I use it today.