Question about PTO slip clutch rebuild

NickTaylor · Jul 28, 2020

Hello,

I have an old JD 513 shredder that I never tested the PTO slip clutch until yesterday. It was totally bound up, so I pulled it off and separated all the parts. They came apart pretty easily. I've watched some videos about reassembly, and it looks like alot of guys polish these discs almost smooth before putting them back together. Mine is definitely rusty from many years of being outside, but do I need to grind all the surfaces down smooth? I've got the manual for the shredder and it doesn't say anything about how to condition the surfaces. Mine looks to be a little different design than most I've seen in the videos on youtube. Are these surfaces meant to be smooth or rough? I don't want to take a grinder to them and destroy them for no reason...

Interested in any advice, thanks!
Nick

Tx Jim · Jul 28, 2020

If it was my slip clutch I'd utilize a wire brush to remove excess rust from metal assemble slip clutch leaving adjustment slightly loose,slip the clutch a little then tighten clutch to the point it just stopped slipping. IMHO that has to be much safer for tractor/cutter driveline/gearbox components that a SC that's frozen solid

5030 · Jul 28, 2020

Tx Jim said:
If it was my slip clutch I'd utilize a wire brush to remove excess rust from metal assemble slip clutch leaving adjustment slightly loose,slip the clutch a little then tighten clutch to the point it just stopped slipping. IMHO that has to be much safer for tractor/cutter driveline/gearbox components that a SC that's frozen solid

Plus one. Clean it, reassemble it and slip it a couple revolutions and then tighten the preload springs to either what you deem a good break torque or to the manufacturers spec. What I do with my rotary cutters is if it slips slightly on engagement (squeaks a tad), it's fine. No squeak is no slip and not good.

NickTaylor · Jul 28, 2020

Thanks!

NickTaylor · Jul 28, 2020

5030 said:
Plus one. Clean it, reassemble it and slip it a couple revolutions and then tighten the preload springs to either what you deem a good break torque or to the manufacturers spec. What I do with my rotary cutters is if it slips slightly on engagement (squeaks a tad), it's fine. No squeak is no slip and not good.

Thanks to you both. This seems reasonable to me. I really didn't want to try and polish these things smooth.

Sawyer Rob · Jul 28, 2020

I don't even clean them, unless it's grease or oil on them.

One good slip before the final adjustment and everything is as clean as it needs to be! BUT, I've not had things as rusty as your pictures show wither...

SR

Zebrafive · Jul 28, 2020

That's heavy rust! I second wire brushing to clean them. Does your manual give a thickness for the fiber discs "end of service" measurement? Now is the time to replace if they need to be.

SeidelRanch · Jul 28, 2020

Plus one to all the replies. I had one all rusted up and locked on a 14' cutter. Just loosened it up and let the PTO slip it a little, then tightened it up just enough to get the job done. I did not want to wear out the pads grinding. It been doing good with just small adjustments if it slips again.