60" Mow Deck/520H PTO Slippage

[akoehler 13]

Hi all, sorry if this post is in the wrong place, first time posting here..

 

I have a still-mostly-new-to-me 520H that I've been having some trouble with. When running a (rather beat up) 60" deck, in taller grass, I can't seem to keep the clutch from slipping, no matter how slow I go.

 

I greased all the zerk fittings on the deck, replaced the rusted-out idler pulley, and everything seemed to spin freely. I added quite a bit of tension to the PTO engagement lever by threading the trunion further onto the PTO linkage (almost difficult to engage now.) In addition, I threw a new clutch on it as the PO seemed to have glazed it over. Still no luck.

 

I thought I might be able to get away with really babying the deck while cutting taller grass (10+ inches in some places) but still couldn't keep the clutch from slipping a little every few minutes. My better 3/4 decided to mow a few days later and I walked out to a plume of smoke... she now knows what burning clutch smells like.

 

This was the final straw for me and that deck between the slippage and the state of it (height adjust was completely non functional as the housing rusted off where it mounted.)

 

Looking around for a smaller deck that may be easier to drive, I found a 42" rear discharge for sale nearby (and it came with a 310-8 on top of it too 😁) and picked it up. I have yet to try it as by the time I got it mounted tonight, it was a little too late to mow.

 

My question concerns the PTO bell: there are two possible locations for a belt to go. If I have more trouble with slippage when I try to mow tomorrow, do you all think it would be worth it to buy a slightly smaller belt (maybe 93" or 94" instead of the normal 95") and mount it on the smaller of the two belt locations? My thinking is it would trade some blade speed for torque.

 

If not, does anyone have any suggestions for what to try next in terms of fixing the slippage?

 

Thanks in advance, I'm really happy to have found this forum. 

[roadapples 6,983]

. Check the metal disc that goes against the clutch. Mine was cupped and the outer 1/2" or so was all that was making contact. Took it to a machinist and had it turned like a brake rotor. Problem solved...

 

[lynnmor 7,302]

 

Download the Owners Manual.

 

Run the belt on the inside groove.

 

Run the engine at full throttle (3600 RPM).

 

Any belt slippage will lead to clutch slippage, check tension and condition.

 

Blades need to be sharp and sharpened correctly.

 

Be sure that the PTO hoop isn't contacting the bell due to failed parts.

 

The 60" deck will work when everything is right, I operated the same setup for years without issue.  I am just 4 miles from Windsor if you need help.

[Ed Kennell 38,048]

Are you sure the PTO is slipping and not the belt.      If the belt sides are worn, the belt will bottom out in the pulley and slip.

 

 

 

Oh, and  to the       I'm just  4 mile south of Red Lion if you need parts.

Edited May 11, 2022 by Ed Kennell

[oldlineman 1,481]

Try mowing tall grass a little taller the first pass and then mow again at your regular setting.

[peter lena 8,589]

@akoehler  ever inspect that pto cone , NEEDLE BEARING ?  sounds like you are , not finding the problem area ,  that rather beat up "60 deck is probably bearing lubrication starved , in addition to related drive movement / function points . would bet that every next  step of drive function , has a rusty / lubrication starved point . would also recommend  the correct , hi temp lubricant .  would recommend  @lynnmor  for advise , insight . pete

[Darb1964 1,042]

Check the mule drive, make sure the spacers are there between the pulleys and that the pulleys aren't wearing on the mule drive. I've seen mule drives wore nearly through.

[akoehler 13]

Wow, thanks for the warm welcomes and outpouring of support!👍🏻 Didn't realize there were so many of you local.

 

8 hours ago, roadapples said:

Check the metal disc that goes against the clutch. Mine was cupped and the outer 1/2" or so was all that was making contact.

Good thinking! I didn't check the wear pattern on the backside of the bell, will do. I actually have a lathe myself so I can touch that up if necessary.

 

6 hours ago, lynnmor said:

Download the Owners Manual.

 

Run the belt on the inside groove.

 

Run the engine at full throttle (3600 RPM).

 

Any belt slippage will lead to clutch slippage, check tension and condition.

 

Blades need to be sharp and sharpened correctly.

 

Be sure that the PTO hoop isn't contacting the bell due to failed parts.

I have the manual, do run at 3600 (my WOT), and have been running the belt on the inside groove (larger pulley.) I'm fairly convinced I set the belt tension correctly after having the first (cheap Amazon belt) slip, wear, and snap... second belt I got tensioned correct. You were right about checking the PTO hoop, PO ran without the pin in the bottom of the hoop and the hoop has the profile of the clutch disk worn into it, corrected that some time ago. Lastly, I have NOT sharpened the blades yet. It's that something I can do by hand (with a benchtop grinder) or do I need to setup a jig to hold the blade at the right angle?

 

2 hours ago, Ed Kennell said:

Are you sure the PTO is slipping and not the belt. If the belt sides are worn, the belt will bottom out in the pulley and slip.

I'm pretty sure it's the PTO, but not 100%, as it could be both. Though when I was running it I could plainly see the bell come to a stop. I don't know which was slipping when I walked out to all of the smoke, but I'd bet it was the clutch burning, not the belt.

 

46 minutes ago, peter lena said:

@akoehler  ever inspect that pto cone , NEEDLE BEARING ?  sounds like you are , not finding the problem area ,  that rather beat up "60 deck is probably bearing lubrication starved , in addition to related drive movement / function points . would bet that every next  step of drive function , has a rusty / lubrication starved point . would also recommend  the correct , hi temp lubricant .  would recommend  @lynnmor  for advise , insight . pete

I have checked the bearing on the inside of the PTO bell (is that the same thing as the PTO cone?) and it doesn't feel locked up. I did throw some high temp bearing grease in there while I was in there tho. The mower deck I greased with #2 lithium grease.

[c-series don 8,676]

You most certainly can sharpen your blades on a bench grinder. You should also balance them, if you don’t already have a balancer you can pick one up at just about any hardware store. 

[peter lena 8,589]

@akoehler  would take it easy on the bench grinder , something  I  never do , always use a small fine flat file , removing minimal metal . not even knowing how the deck lift carriage , fits or works , any lubrication on any of the " movement areas ? how many related rusty areas are there on the deck ?  pto lever trunnion , sloppy fit ? washer it up , lubricate threaded area , mount point . just reflecting to general function , hope you start to see a easing of movement to function , that will tell you something , enhance those areas .  have 3 decks that I regularly use / rotate , stay after all their maintenance , all work with ease , hope you gain on this , pete    

[Handy Don 12,174]

Flat file works the best for me. I start with a single cut medium file and end with a fine double cut. But be sure the file hasn't been dulled by improper use or storage! 

[Bill D 1,915]

Please post some pictures.  Sometimes we can spot a problem that way.  Welcome 😁

[akoehler 13]

Here's the deck that's giving me trouble. Have to post these images separately cause they're too large, sorry.

[akoehler 13]

Here's the position of the trunnion on the PTO linkage.

 

Edit: this is the 42" deck mounted, not the 60", but the trunnion position hasn't changed.

Edited May 11, 2022 by akoehler
Clarification of image.

[akoehler 13]

Here you can see the PO's handiwork on the wheel height adjust.

[lynnmor 7,302]

3 hours ago, akoehler said:

 Lastly, I have NOT sharpened the blades yet. It's that something I can do by hand (with a benchtop grinder) or do I need to setup a jig to hold the blade at the right angle?

 

I always use a bench grinder, a file would take me all winter.  I don't use a jig but it takes some finesse to get it right doing it freehand.  I tried to find a video for you and saw all kinds of poor workmanship, it you need help, again I am right down the road.

 

In your photo, it appears that you have the deck belts all wrong, refer to the manual.

 

 

 

 

[akoehler 13]

26 minutes ago, lynnmor said:

In your photo, it appears that you have the deck belts all wrong, refer to the manual.

Just double checked the manual as well as the sticker on the deck, belts seem to be correct with one uncertainty: due to the quality of the images, I can't tell whether the deck belt goes on the top or bottom pulley. Right now the deck pulley is on the lower of the two and the PTO drive belt is on the upper. The rest of the belt routing matches the diagrams in both the sticker and the manual.

[akoehler 13]

38 minutes ago, lynnmor said:

 again I am right down the road.

Is there a way to PM on this forum? Sorry still new. I wouldn't mind an extra set of eyes to see if there's something obvious I'm overlooking.

[lynnmor 7,302]

1 hour ago, akoehler said:

Just double checked the manual as well as the sticker on the deck, belts seem to be correct with one uncertainty: due to the quality of the images, I can't tell whether the deck belt goes on the top or bottom pulley. Right now the deck pulley is on the lower of the two and the PTO drive belt is on the upper. The rest of the belt routing matches the diagrams in both the sticker and the manual.

That is what I saw, you need to swap positions. I couldn’t determine if the mule drive is correct, it should have the two pulley offset a bit and there should be a spring attached, also look for a grease fitting.

[Ed Kennell 38,048]

3 hours ago, akoehler said:

Just double checked the manual as well as the sticker on the deck, belts seem to be correct with one uncertainty: due to the quality of the images, I can't tell whether the deck belt goes on the top or bottom pulley. Right now the deck pulley is on the lower of the two and the PTO drive belt is on the upper. The rest of the belt routing matches the diagrams in both the sticker and the manual.

The belts look correct to me.   The deck belt gos on the bottom pulley and PTO belt on top.     The PTO belt does look thin.  Is it the correct width?

 

What does look wrong is the attachment at the mid attach-o-matic.      The fork on the deck rod has to hook on the att-o-mat rod.    Yours looks like it is rotated back and not hooked.

[akoehler 13]

1 hour ago, lynnmor said:

That is what I saw, you need to swap positions. I couldn’t determine if the mule drive is correct, it should have the two pulley offset a bit and there should be a spring attached, also look for a grease fitting.

In the picture is the mule drive for the 42" deck as that is what I have on there now. The mule is different for the 60" deck (the 60" mule has the offset pulley.) Tho I don't see a spring on the mule anywhere.

 

I did swap the pulley positions on the 60" deck however and the whole thing feels better. If mowing takes too long with the 42" rear discharge that I just put on there, I might consider putting the 60" back on.

[Ed Kennell 38,048]

Have you checked to see if it is the PTO clutch or the belt slipping?

[akoehler 13]

26 minutes ago, Ed Kennell said:

Have you checked to see if it is the PTO clutch or the belt slipping?

Yeah was definitely the clutch. Watched the bell almost stop. 

[akoehler 13]

Quick update, running the 42" rear discharge deck for the first time and the clutch is handling with ease even in tall grass. Will examine the 60" side discharge in more detail later.

 

Thanks for all the advice everyone, you guys know your stuff and think of everything 👍🏻

[lynnmor 7,302]

This thread has good information on the mule drives.