Mowing TC40A PTO engagement with a rotary mower

   / TC40A PTO engagement with a rotary mower #1  

mundamanu

Silver Member
Joined
Nov 24, 2003
Messages
156
Location
Schoharie, NY
Tractor
TC40A, Ford 8600, MF65
I hooked up my 6' standard duty Woods bush hog to my new TC40A for the first time today. When I engaged the PTO (at about 1300 rpm), the shear bolt broke. It was the first time that I engaged the bush hog this season, so I thought that maybe the blades had frozen up and that was why the shear bolt broke.

I replaced the bolt, checked to make sure the blades were swinging free and tried again. The shear bolt broke.

I replaced the bolt and tried again at idle. This time, I slowly eased the PTO lever back. The bush hog engaged without shearing the bolt. However, because I was paying attention to the bush hog, I didn't realize that I hadn't pushed the PTO lever all the way into position. I freaked out because I remembered reading in the manual that you can damage the PTO clutch if you don't fully engage or disengage the PTO. I quickly slammed the PTO lever down, fully disengaging the PTO.

Then, still at idle, I quickly raised the PTO lever all the way up to the stop, which is how I usually engage the PTO when I run the manure spreader. At idle, the third shear bolt -- my last one -- also broke.

So, the question is, how do you all (especially TC40 owners) engage the PTO with a bush hog? Do you ease the PTO lever up to the stop so that it gradually engages? Do you just raise it up quickly in one quick motion? Is it bad to ease it up? If you just raise it up quickly and it works fine for you, might there be a problem with the bush hog, even though the blades swing free?

Thanks,
Bob
 
   / TC40A PTO engagement with a rotary mower #2  
Bob, you have my sympathy, but it may take awhile to get the hang of it. I always engage and disengage the PTO at the lowest rpm (around 1000 rpm). I've learned just where the exact position is that the PTO will engage when cold and after operating for awhile when the hydraulic fluid heats up. I go to the engage position and wait for the cutter to slowly spin up to speed. Then, I push the lever to full engagement and continue by raising the engine rpm to 540 PTO speed. Many times, I've forgotten to fully engage the PTO and heard the blades slow down under the load of cutting grass. Normally, I just go back to idle and fully engage the PTO without any shearbolt damage. I think it would take quite awhile and constant slipping to do any permanent damage.

When I start to disengage the cutter, I idle back on the throttle and just throw the PTO lever to disengage as soon as the cutter and engine slow down. I did break a shearbolt one time when I disengaged the PTO at full 540 rpm. The PTO brake worked pretty well.

I'd say that with a little practice you will get much better. The 6' cutter will required a little longer to get up to speed than my 5' cutter and also a little more time to come to lower rpm. I've gone through shearbolts like candy and now buy dozens of grade 2 bolts at TSC. All the ones I've broken lately have been legitimate reasons of hitting rocks or stumps, but I always carry three or four bolts with me in my toolbox. I'm not sure, but some cutters require a grade 5 shearbolt and yours may be one of those.
 
   / TC40A PTO engagement with a rotary mower #3  
Does the 40 use the independent pto setup as many of the 8x2 trannies use?

My 5000 / 7610s are that way.. and I engage/disengage mine like jinman does.

On the 2-stage clutch models.. they are even easier to 'slip' in without shock.. ( but ind is just a much nicer setup in the end.. )

Soundguy
 
   / TC40A PTO engagement with a rotary mower
  • Thread Starter
#4  
Thank you for the replies.

I found a few more shear bolts, so I can try it out again without needing to go out and get them.

Now that I know it is okay to gradually engage the PTO, I imagine I won't have any problems.
 
   / TC40A PTO engagement with a rotary mower #5  
If it still breaks the bolt at idle and the system isn't designed with a feather engagement from the manufacture, you can install a PTO slip clutch. They run about a $100 at some places. They work much better but have to be serviced every few month if the cutter isn't used. The service adjustment isn't hard it just takes a little while.
Does anyone know if the TC35/40s have step pressure solenoids to feather the independent PTO?
 
   / TC40A PTO engagement with a rotary mower
  • Thread Starter
#6  
So, I mowed this afternoon with no problems.

I slowly brought the PTO lever up until it gently engaged the blades. Then, as soon as they were spinning, I was able to raise the lever up to the stop. It was no problem after that to bring the RPMs up to PTO speed.

When I shut the PTO off, I idled the engine down until the blades were spinning slowly and then I just disengaged the blades in one motion.

Thanks again for the help.
 
   / TC40A PTO engagement with a rotary mower #7  
That's the one thing I didn't like about some of the first mahindra's i looke dat 3xx and 4xx series.. .. electric solenoid in/out pto engagemnt.

I like the feathered engagement ability of the ind pto on my 7610s.. etc..

Soundguy

JerryG said:
If it still breaks the bolt at idle and the system isn't designed with a feather engagement from the manufacture, you can install a PTO slip clutch. They run about a $100 at some places. They work much better but have to be serviced every few month if the cutter isn't used. The service adjustment isn't hard it just takes a little while.
Does anyone know if the TC35/40s have step pressure solenoids to feather the independent PTO?
 
   / TC40A PTO engagement with a rotary mower #8  
Is your 7610 electric over hydraulic?
 
   / TC40A PTO engagement with a rotary mower #9  
Jerry, the TC30, TC40, and TC45 all have a hydraulic actuated clutch/brake. When you engage the PTO, you divert up to .6 gpm hydraulic flow as a function of the engagement lever position. That allows you to feather the engagement based on flow rather than just pressure. Also, if the hydraulic pump quits pumping, the PTO disengages and the brake sets.
 
   / TC40A PTO engagement with a rotary mower #10  
As far as i know mine is a siilar setup.. .. pretty much just fancy hyds.. but no electrics that I know of.. except a safety switch. ( only on the 7610s.. 5000 don't have the safety switch.. )

Soundguy
 
 
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