Manual PTO Clutch Rebuild and Set Screw Removal Tips

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Clank
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Manual PTO Clutch Rebuild and Set Screw Removal Tips

Post by Clank »

Hi Folks,
The release fingers on my 123's PTO clutch were worn out, so I decided to rebuild it. I had a parts clutch assembly and with a few new parts, I made one good one from the two. I like the overall design. I think it's cool that it's an actual clutch. But there is one big drawback as they get older: removing the set screws. They seize from rusting, which is bad enough, but worse is when some ham fist uses the wrong size Allen key or fails to dig out the dirt so the key fits, and they end up damaging the screw.
To remove mine, I started by digging dirt out of the screws with a pick, so that I could get an Allen key in. I then added some penetrating oil and returned to it the following day. One set of screws was completely missing, and there was only one locking set screw. (For those unaware, there are three special screws with pointed tips that are installed into the pulley first. These lock the assembly to the idler bearing. Each of these has a short flat nosed locking screw that is tightened in place over top, thus securing the bottom screw into place.) I manged to back one screw out far enough past the outer bearing race, but the other was stripped out and completely seized. Fortunately, it was seized partway up the hole, not in it's normal resting position, so it didn't impede me from gently tapping the assembly off of the crank.
So how to get that stripped, seized screw out?
Well, I thought about heating it with a torch but I was concerned about cracking or warping the pulley. I've also had poor luck drilling out these types of screws (maybe I don't have the right bits?), so then I turned to this:
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It used to be called Evapo Rust but now Rust Check is calling it Enviro Rust Wash. Long story short, it's hands down the best thing I've found to dissolve rust from iron and steel. So over the course of a week, I went out to the garage once a day and filled the set screw hole with this using an eye dropper.
At the end, none of my screw extractors would get a hold of the damaged screw, but I found a drill bit, that just barely did.
So very carefully, using a set of vice grips and the drill bit, I turned out the damaged screw. It actually came out easily! Yay!
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After that, it was relatively smooth sailing: parts were replaced, cleaned, painted, adjusted and assembled. I also replaced installed a new clutch basket/starter pulley as the old one had been damaged by someone.
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The story ends well. Almost. Once assembled, the clutch would release, but there was just enough drag that an implement (e.g. my QA-36) would not stop. I tried readjusting the clutch to no avail. Then I removed the three anti rattle springs, and presto! the clutch works fine. I believe the new friction disk and the new clutch basket/starter pulley are just a wee bit tight on clearance, so with the springs installed, they cause it to bind ever so slightly. When spring rolls around and It's had some run in time, I'll reinstall the springs and see if it's better. In the mean time, the clutch works like new, and I hope my story helps someone. Cheers!
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JMotuzick
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Re: Manual PTO Clutch Rebuild and Set Screw Removal Tips

Post by JMotuzick »

Great write up! Thanks for sharing.
I often times leave the rattle springs out, I too find they don’t quite fit right.

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Clank
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Re: Manual PTO Clutch Rebuild and Set Screw Removal Tips

Post by Clank »

Thanks!
Yeah it's kinda weird; that little bit of pressure makes all the difference in my clutch engaging/ disengaging. The starter pulley/clutch basket was new from Kohler and had a lot of paint on it, and then I painted it yellow too, so I'm hoping that once that wears it will allow the friction disk to float more freely when the clutch is disengaged. I'd like to put the springs in, as it is definitely quieter with them in. Cheers!

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Dave C
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Re: Manual PTO Clutch Rebuild and Set Screw Removal Tips

Post by Dave C »

Thanks for that writeup!

Ive found the key to those pesky things is patience mostly! but as you mentioned in your writeup. one big help factor is digging all the dirt out of the hex hole... ive also found that using a nice new hex key each time helps... they do seem to wear. I also have a hex key that is attached to a 3/8 socket drive which i can adapt to my impact screwdriver which sometimes helps break them free without stripping them out. Also at times when i am faced with a pto that is off the tractor but has a set screw still in that refuses to back out- sometimes its possible to send the screw back in and out the other side.
I can tell you that ALOT of these units have hit the scrap bin cause they get broken or set screws get striped out. !
Trying to save cubs... one at a time.......

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Clank
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Re: Manual PTO Clutch Rebuild and Set Screw Removal Tips

Post by Clank »

Those are some excellent points. It's definitely something to walk away from when they're being stubborn,
and for what new Allen keys cost, well worth preventing the aggravation.
In addition, using new set screws (which I did) and putting a little blue loctite or nev-r-seize on is some good insurance for next time.
Just a hint of nev-r-seize though, or it'll sling out all over the place.
The aggravation you save may be your own! lol
You're right on the scrap pile too. One of the clutches I had had an ear broken off where someone tried to get one of those screws out.
I bet that was a bad moment! lol :D

cherrybomb
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Re: Manual PTO Clutch Rebuild and Set Screw Removal Tips

Post by cherrybomb »

This was very informative, another tool in a guys arsenal is left handed center drills,which help you get started exactly on point.In this case you need a left handed twist drill.Works for me.Grainger,McMaster-Car or Fastenal are good sources.

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Clank
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Re: Manual PTO Clutch Rebuild and Set Screw Removal Tips

Post by Clank »

Hey thanks Dean! Good to know! :beer:

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BigMike
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Re: Manual PTO Clutch Rebuild and Set Screw Removal Tips

Post by BigMike »

Great write up!
I have to clarify one thing though. You used "some ham fist".....when referring to Dag it should be ham fisted knuckle head!
How's that Tom? :lol: :lol: :lol:

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Tom Scott
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Re: Manual PTO Clutch Rebuild and Set Screw Removal Tips

Post by Tom Scott »

BM - That's perfect! :lol:
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2182-1, Kwik-Way Loader, 3-pt & rear pto, 442 tiller
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<><

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Clank
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Re: Manual PTO Clutch Rebuild and Set Screw Removal Tips

Post by Clank »

LOL! This post was a work of pure fiction. Any resemblance to persons living or dead, is purely coincidental. :lol:

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BigMike
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Re: Manual PTO Clutch Rebuild and Set Screw Removal Tips

Post by BigMike »

Tom Scott wrote:
Wed Mar 16, 2022 7:17 pm
BM - That's perfect! :lol:
I try :D

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dag1450
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Re: Manual PTO Clutch Rebuild and Set Screw Removal Tips

Post by dag1450 »

Ok. I see how it is. Mike makes a couple lame jokes....but because he is on the leader board of donations.... everyones like .."oh Mike! ...I love you Mike ... Mike your so funny!"
I had some great one liners all set up for guys to expand on ...but do I get any help. No! I see!
127, 1650, 1572, 1872, 2072 . A mower, blower and blade for each.

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BigMike
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Re: Manual PTO Clutch Rebuild and Set Screw Removal Tips

Post by BigMike »

dag1450 wrote:
Fri Mar 18, 2022 4:32 pm
Ok. I see how it is. Mike makes a couple lame jokes....but because he is on the leader board of donations.... everyones like .."oh Mike! ...I love you Mike ... Mike your so funny!"
I had some great one liners all set up for guys to expand on ...but do I get any help. No! I see!
:lol: :lol: :lol: :lol: :lol: :lol: :lol: :mrgreen: :lol: :lol: :lol:

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