520-H Drive Belt Tensioner Pully

[ZTatZAU 6]

Hello All,

 

I'm a new member and this is my first post.  I bought my 520-H new in 1994.  It now has about 500 hours.  I would say my tractor has been "lightly used" for mowing grass in the summer and plowing snow in the winter.  Other than occasional replacement of various belts, it has always been quite reliable.

 

I've recently head some amount of "chattering" noise coming from under the drive belt cover on the right side of the tractor at certain (mid-range) RPMS.  It's been my intention to investigate the chattering but that's been put off because the tractor still operated satisfactorily.  Until this past Friday!  I was about half done plowing snow in the driveway when suddenly the tractor would not move forward or backwards and the plow hydraulic lift no longer operated.  Fearing the worst, I was somewhat relieved to find the transmission drive belt had come off the engine pulley and reinstalled the belt to finish Friday's plowing.

 

Today, with another 2-3" of snow on the ground, I had made about four long passes, when the (original) transmission drive belt came off again.  I found a few threads here on this forum, (before registering today), that drew my attention to the drive belt pulley tensioner which I noticed didn't seem to firmly mounted or secured to the tractor.  There is a small amount of play in the hole through which the tensioner assembly passes through the frame.  While the hole in the frame seems to be ever so slightly enlarged, my hunch is the that the tensioner assembly is no longer securely mounted in the frame and I'd like to tighten whatever is supposed to be holding the tensioner assembly in place.

 

I have an old PDF copy of the 520-H Parts Manual but while the manual shows a diagram and parts list for the transmission drive belt, with engine and transmission pulleys, the diagram does not include the tensioner pulley/assembly and I couldn't find any reference to the drive belt tensioner anywhere else in this parts manual.  Perhaps, this is not the correct parts manual for my 1994 520-H.

 

In any case, I'm hoping some here may be able to direct me to a service manual in the manual section of this forum, (or perhaps the correct parts manual if mine is incorrect) that will show what I need to remove to obtain access to the mounting portion of the tensioner assembly inside the frame; or any other guidance/advice on tightening the belt tensioner assembly.

 

I'm also wondering if the belt might be coming off simply because the original belt has stretch so much that the tensioner is bouncing up and down enough to allow the belt to come off the engine drive pulley.

 

Any suggestions or advice will be much appreciated.

ZT

[daveoman1966 3,762]

I can send you a good replacement idler pulley and idler bar from a 520 parts tractor..   # 39, 40 in this schematic.  $30...shipped.

Bearing is excellent in this [pulley.  

I use Paypal...   or mail me a m. order  

contact me via email...

daveoman@windstream.net

 

[ZTatZAU 6]

Thanks for your reply Daveoman1966!

AT this point it's still a bit early to know what all needs replacing but the diagram you posted (showing the idler pulley) has helped a great deal by showing where the parts associated with the idler pulley are shown in the PC and, thanks to your post,  I now know what I'm dealing with on the inside of the frame.

 

My pulley looks to be in good shape and spins freely on the idler shaft's "pulley axle".  So right now I'm thinking the "excess play" problem may be a worn bushing (# 43 on your diagram) at the other end of the idler shaft.  But being new to all this I'm not yet sure.

 

Before anything else though, I need to first remove the left side cover to see what's going on at the left end of the idler shaft.  To do so, I first need to remove the 3/32 x 5/8 SPIROL PIN in the brake release lever to remove the lever and then the left side cover.

 

I've never dealt with a SPIROL PIN before.  Should this pin push out fairly easily with a drift pin without breaking the plastic brake release lever?  Can the same SPIROL PIN be reused upon re-assembly or are the SPIROL PINS a one shot deal?

 

It may be that I'll eventually find a worn idler shaft and might very well take you up on your offer.

ZT

[lynnmor 7,354]

If you press against the drift pin to take up the play while hammering it out, removal should be easy.  I was always able to reuse the pin.  Putting a nail thru to align the holes helps when installing.

 

The original pulley is expensive, I use a common pulley and add a spacer to save quite a bit.

[ZTatZAU 6]

7 minutes ago, lynnmor said:

... If you press against the drift pin to take up the play while hammering it out, removal should be easy...

 

Thanks much lynnmor!

By the above do you mean backing up the bottom of the plastic brake release lever with a bucking bar or something heavy while driving the pin out from the top?

PLMK!  ZT

[lynnmor 7,354]

1 minute ago, ZTatZAU said:

 

Thanks much lynnmor!

By the above do you mean backing up the bottom of the plastic brake release lever with a bucking bar or something heavy while driving the pin out from the top?

PLMK!  ZT

I just push it against the side of the hole.

[ZTatZAU 6]

18 minutes ago, lynnmor said:

I just push it against the side of the hole.

I appreciate your reply lynnmor but I'm still not sure I know what you mean.

ZT

 

 

Edited February 10, 2020 by ZTatZAU
Photo added for clarity.

[lynnmor 7,354]

Put your drive punch on the pin and push it till the shaft hits the side of the hole, then hammer.

[ZTatZAU 6]

5 minutes ago, lynnmor said:

Put your drive punch on the pin and push it till the shaft hits the side of the hole, then hammer.

OK!  So, in other words, just apply some downward pressure on the drive punch to keep it tightly up against the pin while hammering... is that right?

[lynnmor 7,354]

Yes! But also the shaft against the hole.

Edited February 10, 2020 by lynnmor

[ZTatZAU 6]

Thanks lynmoor.  I appreciate your patience with this newbie!  I tapped a bit with a 3/32 drill bit, as I don't have a 3/32 pin punch. but didn't move the pin.  I'll try to pick up the correct tool tomorrow and try again.

 

I'll post back with a  progress report or perhaps additional questions.

 

Thanks again for your assistance.

ZT

[ohiofarmer 3,276]

  The problem you are having was experienced by me. There is a plastic bushing that passes over the shaft and is meant to isolate the thin sheet metal of the transmission tunnel from wearing , The place it wears is on the right side of the tractor looking from a seated position where the idler pulley arm attaches to the shaft that passes through the transmission tunnel  What happens is the sheet metal cuts into the shaft on part number 40 of the illustration after the plastic bushing wears through. The shaft, in turn wears away the round hole in the transmission tunnel into an oblong hole . Mine was very bad, and I fixed it by placing a sintered bronze bushing into the oblong hole and then using heavy washers to also stabilize it.   Not a cosmetically good repair, but it works pretty well.   Also you will not see the repair once the shield is back on.

 Once those things wear an oblong hole, the shaft sets up an orbital vibration, and they wear out at an accelerated rate.   Wheel horse saw this problem and engineered an air shock to take out the vibration. at least they did on my 416-8 of a later model year..

  I think you will want pictures, but it is late at night.  I also am located in the Midwest close to interstates 70 and 75, if that helps.i can show you the repaired tractors involved, which is better than a picture.  

Edited February 10, 2020 by ohiofarmer

[ZTatZAU 6]

Ohiofarmer, I appreciated your thoughtful reply.  What you described is exactly what I expect to see once I get everything uncovered.  I hope the hole in the right side tranny tunnel is not excessive.  I can already see the other end of the shaft has noticlable play where it passes through the left side of the tunnel.  I also can see part of or what's left of the "Washer-Wave" (#45) which has slid away from the left side of the tunnel toward the center of the shaft.  So far, having not yet successfully removed the roll pin from the brake release lever, I cannot remove the left side cover to actually see what's going on there.

 

I'll get back on this tomorrow once I get a decent 3/32 pin punch and get the left side dis-assembled.

 

I appreciate the offer of a personal look-see at your bushing repairs but I'm in northern IL and not very close to Greenville, OH.  But if I wind up finding anything as bad as what you found, I'd very much appreciate having a look at the pictures of your repair.

 

Thanks again for your reply!

 

ZT

[daveoman1966 3,762]

1 hour ago, ZTatZAU said:

Ohiofarmer, I appreciated your thoughtful reply.  What you described is exactly what I expect to see once I get everything uncovered.  I hope the hole in the right side tranny tunnel is not excessive.  I can already see the other end of the shaft has noticlable play where it passes through the left side of the tunnel.  I also can see part of or what's left of the "Washer-Wave" (#45) which has slid away from the left side of the tunnel toward the center of the shaft.  So far, having not yet successfully removed the roll pin from the brake release lever, I cannot remove the left side cover to actually see what's going on there.

 

I'll get back on this tomorrow once I get a decent 3/32 pin punch and get the left side dis-assembled.

 

I appreciate the offer of a personal look-see at your bushing repairs but I'm in northern IL and not very close to Greenville, OH.  But if I wind up finding anything as bad as what you found, I'd very much appreciate having a look at the pictures of your repair.

 

Thanks again for your reply!

 

ZT

If you've not planned to, buy a ROLL PIN punch set...$20 or so... for sizes 1/16 thru 5/16 or so.  These punches have a dimple on the end to preclude flaring out the roll pin.  Wheelhorse uses roll pins a lot and a roll pin punch set is a good investment.     

[ZTatZAU 6]

Yep!  I'm planning on picking up a set of roll pin punches tomorrow.  "Uhhh!",  that is after looking at the clock, later today!

Thanks again for your help Daveoman!

ZT

[ZTatZAU 6]

PROGRESS REPORT!  I apologize for the excess verbiage but please keep in mind that I'm pretty new to this and don't yet have a grasp on all the correct terminology.

 

So far today I have everything dis-assembled and I think I've dodged the biggest bullet in so far as I don't think I've significantly damaged the idler shaft holes in either the left or right frame members.

 

17 hours ago, ohiofarmer said:

...The shaft, in turn wears away the round hole in the transmission tunnel into an oblong hole ...

 

Fortunately, the Right Side Idler Shaft Hole is still essentially round with ID measurements of 0.575 - 0.577".  I couldn't fit my micrometer in close enough to measure the Left Side Idler Shaft Hole but it looks to be essentially undamaged with the punched hole's "shoulder" inside the frame rail is still intact though the little shoulder may be worn a bit thinner than it started out.  The Idler Pulley and its Bearing both look to be in good shape.  Any comments on these findings would be much appreciated.

 

The idler Shaft itself however, does appear to be worn on both ends where the shaft passes through the left and right side rails.  There appears to be slightly more wear on the Left end of the Shaft (0.018 - 0.012") than on the Right end of the Shaft (0.008 - 011").  Whether this amount of wear at the ends of the Idler Shaft warrants replacement, I don't really know; but would appreciate hearing what you all think about this.  (If so I do know where I can get a replacement shaft.

 

21 hours ago, daveoman1966 said:

I can send you a good replacement idler pulley and idler bar from a 520 parts tractor

Thanks Daveoman1966!)

 

I do have a couple of other questions...

1)  Can anyone tell me what the two small beveled holes, above and below the left side idler shaft hole, are for.  Should there be something mounted inside or outside the left frame rail with bolts or screws through these two holes?

2)  I'm still unsure about where the wave washer, flat washer, and bushing are supposed to be located on the idler shaft.  Is the bushing supposed to be inserted in the Right Side Hole from the outside of the frame rail with the flat washer and then the wave washer outboard of the frame rail and bushing between the frame and the idler pulley shaft arm?

 

My local Toro dealer does have the drive belt and idler shaft bushing (plastic - though my original bushing was metal) in stock and I plan to pick up one of each soon.  Depending on the comments and/or any advice I receive on the above info/questions will determine whether I put my tractor back together with only a new belt and bushing or delve further into this project by replacing the idler shaft.

 

I am happy to have found this forum and appreciate all of you who are willing to share their experience and expertise with others like me.

ZT

[cleat 6,339]

 

Hydro belt tension pivot rod plans.pdf

Wheel Horse hydro belt tension pivot rod.pdf

 

I have made up new rods to replace my worn ones.

Only real difference is a cotter key verses an E-clip to hold it in place.

 

Edited February 11, 2020 by cleat

[ZTatZAU 6]

1 hour ago, cleat said:

I have made up new rods to replace my worn ones.

Only real difference is a cotter key verses an E-clip to hold it in place.

Very nice work cleat!  I admire your ingenuity and resourcefulness!

 

Other than what appears to be a bent and broken shaft, would you have gone through all this work solely because of the minor wear I see at the e-clip end of your original shaft?

I sure hope my current project doesn't come to anything like this; but I guess, "ya gotta' do... what ya gotta' do".

 

Thanks for sharing!  ZT

[ohiofarmer 3,276]

   From what I see, you only have minor wear. Mine was worn so badly that I had to grind little areas out of the  transmission tunnel to receive a flanged bearing in a greatly oversized oblong hole. For all who are reading here, waterproof grease is your friend.     These parts are out of sight and out of mind and when these tractors get 1000 hours on them without replacement, it is probably too late.  Another thing I found is that that tensioner spring is prone to bouncing and I speculate that it is because it is so short.  I cut a section out of a motorcycle tube and use that as my spring.  The belt does not vibrate and wear so quickly either.

 

  I am not saying that my way is the best, but it works pretty well for me. These tractors get used pretty hard out in the country where we measure our yards  by the acre and also may mow the county side ditch to show off our crops.  The older series tractors do not have as many wear points or use nearly the fuel to mow the same acreage but there is a trade off with power and speed with a 48'" deck

[ZTatZAU 6]

Thanks for your comments and advice ohiofarmer!

29 minutes ago, ohiofarmer said:

From what I see, you only have minor wear...

  I picked up a couple of the (METAL) idler arm bushings and new belt today at my local TORO dealer.  I bought two of the bushings simply because they were metal and not plastic.  Based on the pictures and wear measurements on my idler bar above, do you think it a good idea to re-use my idler bar in its present condition?

 

Also, can you tell me the purpose of the two holes I pointed out on the left side of the frame in the second picture above?

 

ZT

Edited February 12, 2020 by ZTatZAU
Added the last question.

[lynnmor 7,354]

A new shaft in new bushings would last a very long time if you keep them oiled.  The worn shaft will wear out the new bushings much faster.  I remove the seat, fender and gas tank at winter changeover time and thoroughly wash out debris, let dry and then oil all moving joints except the speed control.  Leaving grass and debris in there year round will have rust forming all the time.

 

Wheel Horse used various mechanisms depending on transmissions and designs, those extra holes are nothing to obsess over.

[ZTatZAU 6]

12 hours ago, lynnmor said:

A new shaft in new bushings would last a very long time if you keep them oiled.  The worn shaft will wear out the new bushings much faster.  I remove the seat, fender and gas tank at winter changeover time and thoroughly wash out debris, let dry and then oil all moving joints except the speed control.  Leaving grass and debris in there year round will have rust forming all the time.

 

Wheel Horse used various mechanisms depending on transmissions and designs, those extra holes are nothing to obsess over.

Thanks again for your reply lynnmor!  Your thoughts and comments are appreciated.  Ive always tried to keep my 520-H reasonably clean but I was surprised at the amount of dried up grass clippings I found inside my transmission tunnel when I got everything apart.

 

I'm on the road for a few days so this project is on hold until I get back home.  My plan is to put everything back together with the new bushing and my original idler bar for now but, having obtained an extra new bushing, I'll keep my eye out for a new idler bar to have on hand if needed in the future.

 

ZT

 

[ZTatZAU 6]

Well, I put my tractor back together and was all ready for the big snow storm that never showed up!  But I've sure learned a lot about my tractor in the process.

On ‎2‎/‎11‎/‎2020 at 9:23 PM, ohiofarmer said:

From what I see, you only have minor (idler bar) wear... For all who are reading here, waterproof grease is your friend.     These parts are out of sight and out of mind and when these tractors get 1000 hours on them without replacement, it is probably too late.

I re-used my original idler bar and tensioner pulley with a new bushing and hardware... well greased at both ends!

On ‎2‎/‎12‎/‎2020 at 8:29 AM, lynnmor said:

A new shaft in new bushings would last a very long time if you keep them oiled.  The worn shaft will wear out the new bushings much faster.

Only time will tell how long my old idler shaft, well greased, in a new bushing will last.

 

I've come to the conclusion that the drive belt coming off really had more to do with the condition of my transmission drive pulley than with the condition of my idler bar tension pulley assembly.  While tmy idler bar had some wear and it's original bushing had disintegrated, the internal bore of my transmission drive pulley was trashed, with large chunks of the bore's internal surface missing, allowing the pulley to wobble and migrate inward on the transmission shaft eroding the bearing surface on the inboard side of the pulley hub.

 

I replaced the drive belt, drive pulley, fan, and the broken 1/4"-20x5/8" attaching bolt with new Toro parts.  I found it odd that the broken attaching bolt, rather than shearing off flush with the end of the shaft or just under the head of the bolt,,, it was the last 1/8" of the 5/8" bolt, at the tip of the bolt, that had broken off down at the bottom of the threaded hole.

 

By the way!  If anyone is wondering, despite what is shown in the Toro parts catalog and what you might hear from the Toro "Parts Specialists", a new transmission drive pulley (p/n 108316) purchased today from Toro WILL NOT HAVE SETSCREWS or any provision for setscrews!

 

So everything is back together now, with the drive belt running straight and true and smoothly!  It is also much quieter now.  I'll be paying much more attention to what's going on under the tractor's side covers from now on!

 

My thanks again to everyone here who provided insight and advice!  ZT

[chex313 123]

I was pretty sure I had this problem, so I bookmarked this thread. So any suggestions for repair as opposed to replacement is appreciated. 

 

The shaft is 1/2' and the hole will be enlarged to 3/4"

 

I think I want to put a flange bushing on the shaft both to cover the worn part of the shaft and fill the elongated holes. Is this the type I am looking for? Or is it called something else. I looked under their bushing section but did not find a match. 

 

https://www.mcmaster.com/bushings/bearings-3/oil-embedded-flanged-sleeve-bearings-7/

 

EDIT: Or something like this? https://www.amazon.com/Hillman-58102-Flange-Bearing-Bronze/dp/B00MND9FJO/ref=pd_sbs_328_3/141-8980158-6962310?_encoding=UTF8&pd_rd_i=B00MND9FJO&pd_rd_r=14e8472c-0fb9-4455-8c19-da18da1b7ea9&pd_rd_w=jow0p&pd_rd_wg=zGBCN&pf_rd_p=d9804894-61b7-40b3-ba58-197116cffd9d&pf_rd_r=CSSSXM3546CA37N7VYKR&psc=1&refRID=CSSSXM3546CA37N7VYKR

 

Diver side is the 2nd pic(Where the c clip goes)

 

 

 

 

Edited June 11, 2020 by chex313

[chex313 123]

Double post

Edited June 14, 2020 by chex313
double post