312H belt ?

[Ed Kennell 35,484]

I thought I'd have an easy one today with some great seat time .       The fresh 4" wet snow was a perfect plow snow.    The  neighbors had left  for work and school so I had fewer vehicles to plow around.

It was a warm 32F when I started at 8:30 am so I took the 312H and cleared 2/3s of the five driveways when I lost the hydro ..no lift and no movement.   A quick look and I could see the drive belt was in a bad way.

Walked back to the barn and got the 520H and plowed another drive when the lift quit.      Drove him a 1/4 mile back  home with the 54incher dragging on the state road.  The wear bar should be sharp now.

I found the hairpin clip sheared off on the lift trunnion  way up there in the rock shaft.    more        New trunnion, washer, and clip and i finished the five driveways. Then towed the 312 home and took off the belt guard and cut the belt to get it off. It was wedged down in behind the tension pulley.    Ever see one worn like this?  I'm guessin  it jump up on the sharp edge of one of the Vee  pulleys and ran there for a while before it jumped off.

 

Is this the correct belt for an '86 312H ?       Ya got a NAPA eqiuiv Mike?     I'll check TSC first.

 

[ebinmaine 62,889]

Kind of thought the hydros were a 7478

[gwest_ca-(File Mod) 10,474]

Transmission drive belt 108501 - (HB/5L x 81.50" or 5/8" x 81.5")

 

Tractor drive belt # 7478 replaces # 4535 - (HB/5L x 84.22" or 5/8" x 84.22") was used up to about 1980

[1995 520H+96+97 935]

[Blackhood Bill 720]

Even though a belt is stamped for the correct size, I always try (key word - try) to remember to put it on a belt sizer just to double check it. I have found them stamped for the correct size just to be to long or short.

[SylvanLakeWH 24,031]

Sounds like you’re having a Murphy’s belt day... 

[ebinmaine 62,889]

31 minutes ago, Blackhood Bill said:

Even though a belt is stamped for the correct size, I always try (key word - try) to remember to put it on a belt sizer just to double check it. I have found them stamped for the correct size just to be to long or short.

 

I've done that with a white colored Dayco brand belt...

Good thing that didn't cause several hours of confusion or mental anguish or anything like that....

[squonk 38,809]

Napa 5L820W

[squonk 38,809]

If you put a worn belt on a belt sizer it may give you the wrong size. When the sides wear they fit deeper in the pullies and do the exact same thing on a belt sizer. An 82" belt maye read 82 1/2" on a sizer

[Blackhood Bill 720]

Well let me clarify myself. I’m talking when I buy a new belt if possible, I try to put on s belt sizer if I remember 

[Ed Kennell 35,484]

43 minutes ago, squonk said:

Napa 5L820W

Thanks mike. I assume that is a 5/8 X 82" .     My local TSC has a  green kevlar 81  and 82 incher in stock.   I'll buy them both and try the 81 first. If no go, I'll use the 82 and return the  one that doesn't fit.

 

BTW, my old belt  measures exactly 81.5"   along the outside of the belt.     There is wear on the sides that would cause it to measure long on a belt measure.   There is no, or very little wear on the outside, so that length is usually correct on a new or old belt.

[squonk 38,809]

1 minute ago, Ed Kennell said:

Thanks mike. I assume that is a 5/8 X 82" .     My local TSC has a  green kevlar 81  and 82 incher in stock.   I'll buy them both and try the 81 first. If no go, I'll use the 82 and return the  one that doesn't fit.

 

BTW, my old belt  measures exactly 81.5"   along the outside of the belt.     There is wear on the sides that would cause it to measure long on a belt measure.   There is no, or very little wear on the outside, so that length is usually correct on a new or old belt.

[Ed Kennell 35,484]

Installing a belt on a 312H outside at 28 F with arthritic hands is no pleasure.    Had to take off the belt guard, the foot rest, the tensioner pulley, and all the PTO engagement mechanism,

 

My hands were nearly frozen, so I put on the easier 82" belt so I could move her inside.   I'll try the 81" inside in the warm  after I thaw out these hands.

[Ed Kennell 35,484]

Sure glad I had a backup plow .....or two.

[Ed Kennell 35,484]

OK, I got the 82" long belt on and moved the tractor inside.    As much as I prefer hydros, the fact is, when the drive belt fails, you can not lift the blade or move the tractor easily as you can with a gear drive.

This is what I had with the 82" belt and I believe this is probably what caused the old belt to fail.   I am convinced the wear on the sides of the old belt allowed it to sit deeper in the Vee pulleys causing the tensioner pulley to sit too low and the lower drive  belt got into the idler pulley  and the inside edge of the idler pulley actually cut the groove in  the old belt.

 

So, I took the 82" off and installed the 81" which looked much better.     While it was inside in the warm, I cleaned and greased all bearings .

 

This was a real challenge to install this one inch shorter belt.

In addition to the belt guard, the foot rest, and PTO,  I had to remove the tensioner pulley and the upper PTO bracket that had a rigid belt guide that would not allow the belt to pass into the engine drive pulley.  

There is also a belt guide at the bottom of the drive pulley.   Neither of these guides serve a purpose on the 312H as the belt tensioner is always engaged.  There is no release on this tractor so the belt is always tight.     The one on the bottom had clearance so I left it in place, I removed the top one.   You can see it here welded to the upper PTO bracket.

 

 

And after I cut it off.

 

The only way I could get this belt on was to position it between the hydro drive pulley and the fan. This gave me barely enough length to roll it over the engine clutch plate onto the engine drive pulley.

Then I was able to roll it on to the hydro drive pulley.   Then install the tensioner pulley and connect the tensioner spring.   In hind sight, it may have been easier to remove the clutch plate.

 

So, I'm back in business.    This is the belt I used and I returned the 82" for a full $24.99 refund.

 

 

[squonk 38,809]

 No belt release? I never noticed that. Happy Motoring! 

[WVHillbilly520H 10,369]

@Ed Kennell, I wonder if that engine could have been a replacement from a gear drive tractor and they didn't take the time to change out the PTO brackets/belt guides?

[Ed Kennell 35,484]

15 minutes ago, WVHillbilly520H said:

@Ed Kennell, I wonder if that engine could have been a replacement from a gear drive tractor and they didn't take the time to change out the PTO brackets/belt guides?

 

Knowing where it came from, I wouldn't think so Jeff.    Would a gear drive engine  have a smaller drive  pulley?

[ebinmaine 62,889]

2 minutes ago, Ed Kennell said:

 

Knowing where it came from, I wouldn't think so Jeff.    Would a gear drive engine  have a smaller drive  pulley?

It does. 

Inch or so smaller. 

[WVHillbilly520H 10,369]

1 minute ago, Ed Kennell said:

 

Knowing where it came from, I wouldn't think so Jeff.    Would a gear drive engine  have a smaller drive  pulley?

That I can't tell you, I did have a 312-8 but sold it this past summer, maybe WH just used the same set-up on the engines to save money in assembly whether gear or hydro.

[Ed Kennell 35,484]

1 minute ago, WVHillbilly520H said:

 maybe WH just used the same set-up on the engines to save money in assembly whether gear or hydro.

That's what I was thinking .     A lot of the hydros had a belt release so the probably used the existing brackets with the belt guides on them all.

[Handy Don 10,522]

I have only worked on two hydros, but I unhooked the spring and removed the tensioner (clutch) pulley to get the belts off. Reversed the steps to get them on.

'95 520-H doesn't have a clutch for the hydro and it can be pushed (slowly) pretty easily.

'88 518-H had a clutch and was a bear to move even with the clutch disengaged.