Slip clutch smoking

[Dougwatts]

I hate to admit this, but twice I've put my Deere MX5 rotary cutter in situations that have resulted in the slip clutch becoming very hot, with lots of smoke pouring out. Don't waste your time telling me I shouldn't do that, or I should pay more attention to what I'm cutting - I've already berated myself.
Today was the second time. After the clutch cooled down a little, I continued mowing, albeit more carefully and with more awareness.
My questions - how can you tell when you've ruined the clutch? (When the blades no longer turn?) Can the clutches be disassembled and overhauled? Is this a preventive maintenance item, or do you wait until it fails.
Thanks for your thoughts.

 

[Rch]

I burned up a slipclutch on a Landpride 5' rotary cutter in a similar fashion. Eventually the clutch wouldn't handle the load in long grass. The dealer rebuilt it for ~ $70 /forums/images/graemlins/frown.gif

 

[RonR]

It's a pretty straighforward job to DIY, once you buy the pads. Essentially the slip clutch is two or more steel plates with some hard disk friction material between them. When it slips, this friction material is what smokes. Depending on what they make them from now, it might be different, but it used to be is you smoked them much, they would glaze over and not work right again.

The key step is to MEASURE the spring length on the bolts compressing the springs. This is how you know what proper tension is on the springs. If you have a manual, it should specify the spring length as well. They all need to be the exact same spring length, as close as you can measure it.

Resist the urge to simply tighten the springs on the plates you now have. That could negate the slip clutch working and break something 'portant.

If you go totally to sleep and smoke the disks for a long time, I suspose it is possible to warp the steel plates, which probably makes them worthless.

In a previous life, I worked on ag stuff. We had one lawsuit that we simulated how a guy said he got hurt. We used the same model tractor(about 100HP) and baler. He said he got off the tractor with it running at PTO speed, and walked around the unit for "two minutes" with the slip clutch, a big one, slipping, when it suddenly unplugged and caught him.

Our test, which the lawyers videotaped, showed a HUGE cloud of smoke with the drive train locked up and the clutch slipping. When the two minutes finally ended, the clutch was on fire and the shield above it had melted from the heat generated..........
Suppose this is more than you wanted to know, but I found it interesting.

Hope this helps.

Ron

 

[Jim_Fisher]

Dougwatts,


</font><font color="blue" class="small">( twice I've put my Deere MX5 rotary cutter in situations that have resulted in the slip clutch becoming very hot, with lots of smoke pouring out. )</font>

Sounds like it might not be tensioned correctly. Mine only slips if I hit something that is really substantial. Heavy brush just pulls the tractor down.


</font><font color="blue" class="small">( Can the clutches be disassembled and overhauled? Is this a preventive maintenance item, or do you wait until it fails. )</font>

The clutch can be rebuilt if necessary. I have the technical manual for the MX and HX mowers at home and can give you the particulars. There is a measurement that is needed to set the proper tension. Unfortunately, I'm about three hundred miles from home right now and don't plan to be back until after the eighteenth of this month.

Preventive maintenance consists of loosening the adjustment and verifying that the facings aren't stuck to the plates by slipping the clutch. Then the adjustment is tightened to the proper measurement/tension.

I don't remember the procedure exactly, but I think the particulars are in the owners manual.

 

[em14]

Doug,
It sounds to me like you may need to adjust the clutch. But then, if you were cutting in heavier, more dense than you normally do then the clutch is doing it's job! Make sure you adjust the each spring the same as you adjust the clutch ... It is easy to miss one ... I think one of the best ways to be sure they are equally adjusted is to measure them as you go. Adjust one to oh say 1" then do the next and so on. I think it beats the daylights out of a shear pin ...
Leo

 

[Jim_Fisher]

Dougwatts,

I just found the manual on Deere's site. MX5 manual on line

See Disassembling and Inspecting Slip Clutch-MX5 and MX6 for details.

 

[greg_g]

</font><font color="blue" class="small">( The key step is to MEASURE the spring length on the bolts compressing the springs. This is how you know what proper tension is on the springs. If you have a manual, it should specify the spring length as well. They all need to be the exact same spring length, as close as you can measure it. )</font>
For clarification, the spring length adjustment is made based upon PTO horsepower of the tractor spinning the shaft. The mower (or slip clutch) manual should specify the overall spring length at various levels of applied horsepower. It's a simple box wrench adjustment.

I suspect the spring adjustments may have been too slack, or perhaps never made in the first place. A BX2200 has 16.7 PTO horsepower, but unfortunately my spring length chart starts at 20hp (28.5 mm). The higher the hp, the more you tighten (shorten) the springs.

//greg//

 

[RonR]

Greg,

You are probably correct in your statement about HP. In my tiller manual, it just shows one length to set the slip clutch to. Maybe they just assume you will be in the proper range of HP for that size rototiller, so they only provide one length??????

THKS.
Ron

 

[Dougwatts]

All,

Thanks so much for your quick replies. What a privilege to be able to get information from you folks!