C125 - Which correct transmission drive belt?

[Billyboy 2]

Good evening,

I write as a new member from England. I have several hydrostatic Wheelhorses, two 418C's and a 417A. The transmission drive belt from the Eaton hydrostatic to the Kohler Magnum 18hp engine is clearly shown as a 108501 on Toro Partsviewer.

I also have a pretty immaculate 1980 C125 8 speed ( Model 01-12K801 ) but the transmission drive belt lists several different ones. The front runner is 7473 but the above 108501 is also listed along with 106496 and 107939. The 108501 is 81" long, the 7473 is 82". Any of you specialist guys know which is best as I don't want it be too tight but also not flop about either?

The C125 also eats it's mower drive belts from PTO pulley to deck. ( using 108834 but PartsViewer for the model shows 108334 - a misprint I think as all other 42" Rear discharge decks seem to use the same PTO to deck number 108834 ). The front idler pulleys and pto bearings all seem fine but looking from above from the front the belt it seems pulled over slightly towards the engine. The belts wear their sides then break. I suspect engine mounts as the Kohler 301 does vibrate a bit, particularly at idle. My local garden machine expert has also mentioned the clutch

bearings getting too hot and ruining the belts. Anyone had the problem please? Any ideas?

It seems from both the above Wheelhorse were clever with their original design in that the distance from the pulley of whatever Kohler engine is fitted to transmission drive pulley is fitted is the same regardless of engine model. Also all belts feeding the rear discharge 42" deck seem to be the same regardless of engine model.

Greetings from Brexit and am in awe of the knowledge on your site!

Bill

[tunahead72 2,432]

Hi Bill, and welcome aboard!

 

As you noticed, the PartsViewer doesn't always tell you exactly which tractor goes with each part.  You may want to look for an actual parts manual here on RedSquare, or directly from Toro.

 

Somebody check my work, but I believe the 7473 is the belt you're looking for.  I'm taking an educated guess from a parts manual I have here at home for the earlier but very similar C-xx1 series, which shows the 107939 belt on the C-161 twin 8-speed and 106496 for the C-161 twin automatic.  I don't see the 108501, but there is a 7478 for the smaller automatics.

 

[DougC 2,641]

Hello and     Billyboy!    Enjoy the forum.    

[gwest_ca-(File Mod) 11,096]

It does get confusing. The single cylinder engines often use a different drive belt than the twin-cylinder models and then add the gear and hydro transmissions gives us 4 different belts.

Have been adding the belt numbers and dimensions to the IPL's and TIPL's for each model.

Garry

[Billyboy 2]

Thanks for your welcomes and time spent on my problem already guys.

7473 seems the way to go. Anyone any thoughts on the mower belt wearing problem please?

billyboy

[jackhammer 546]

Welcome here Bill.

[jay bee 909]

 to   You will find some answers here!!!

 

Jim

[Mr Greedy 0]

Any one else able to help with this? My dad has a C125 but model S/N sticker is no longer present.

 

I also cannot find instruction on how to change the PTO belt. This belt is nearly new, but seems way too slack. I've found online videos for drive belt and mower deck belt, but not the PTO belt.

[gwest_ca-(File Mod) 11,096]

Pto drive belts are specific to the attachment not the tractor.

What does it drive?

If a mower deck, what is the width of cut, how many blades and side or rear discharge?

 

The C-125 was produced 1980-1984 with 8-speed transmissions and 1980-1981 with hydro transmissions.

 

If you post all the numbers off the engine ID decal with the Kohler serial number we may be able to identify the tractor model number.

 

Garry

[WVHillbilly520H 10,374]

21 hours ago, Mr Greedy said:

Any one else able to help with this? My dad has a C125 but model S/N sticker is no longer present.

 

I also cannot find instruction on how to change the PTO belt. This belt is nearly new, but seems way too slack. I've found online videos for drive belt and mower deck belt, but not the PTO belt.

Have tried adjusting the front mule drive tensioner to remove the slack? You would need to turn the black knob counter clockwise direction to tighten the belt and clockwise to loosen it.

[Mr Greedy 0]

Hi all, I'm still on with this.

 

So, we managed to tighten the mule drive using the helpful instruction above, but at the end of the summer the mower deck belt snapped. 

 

My dad bought this off someone who "renovates" these tractors (covers them in rubbish paint) and he advised a 97" x 1/2" belt for the PTO, and a 79" x 1/2" belt for the mower deck.

 

The snapped mower belt measures 80.5" (but it is snapped and not cleanly) and 1/2" wide. The new 79" belt is too small to get on the mower deck. The deck is off and the adjuster/idler is pryed to the smallest size. Still not a chance to get the 79" on. Could 80" be the correct size? Seems it would fit just right.

I've read the belts don't really stretch.

 

I've cut the PTO belt off as much as anything to get an accurate measurment, and it's exactly 96" long, and 7"16" wide, but the width reduction could be due to wear as its been worn away rubbing on the pulleys? I would guess at a 96" x 1/2" replacement. 

 

HOWEVER, if I measure the centre double drive pulley/spindle on the mower deck, it reveals the lower (mower?) pulley is 1/2" wide inside at the outer edge, and the upper (PTO drive?) pulley is 5/8" wide inside at the outer edge.

 

Does this indicate belts of different widths are required?

Should the belts ride flush with the outer edge of the pulley when new (not touching the base of the V groove), but as they wear, they move towards the centre of the pulley, hence the mule drive adjustment to take out slack?

 

Sorry, this is a lot, but it seems so difficult, and no one from Toro can give sound advice. Apparently you 'can't measure this', you need to know everything you have so you can look up the correct belt. Not sure I'm buying this. A last resort would be to replace all the pulleys so I know I have the correct profile.

 

How many pulley/belt V-profiles are there? A few? Hundreds?

 

There are no stickers on the tractor except the C125 8 speed on the hood and the Kohler engine sticker. I guess the old stickers have been "renovated" (painted over or removed).

Edited February 14, 2020 by Mr Greedy

[pfrederi 17,874]

10 minutes ago, Mr Greedy said:

Hi all, I'm still on with this.

 

So, we managed to tighten the mule drive using the helpful instruction above, but at the end of the summer the mower deck belts snapped. 

 

My dad bought this off someone who "renovates" these tractors (covers them in rubbish paint) and he advised a 97" x 1/2" belt for the PTO, and a 79" x 1/2" belt for the mower deck.

 

The snapped mower belt measures 80.5" (but it is snapped and not cleanly) and 1/2" wide. The new 79" belt is too small to get on the mower deck. The deck is off and the adjusted is pryed to the smallest size. Still not a chance to get it on. Could 80" be the correct size? Seems it would fit just right.

 

I've cut the PTO belt off, and it's exactly 96" long, and 7"16" wide, but the width reduction could be due to wear on the pulleys? I would guess at a 96" x 1/2" replacement. 

 

HOWEVER, if I measure the centre double pulley spindle on the mower deck, it reveals the lower (mower?) pulley is 1/2" wide inside at the outer edge, and the upper (PTO drive?) pulley is 5/8" wide inside at the outer edge.

 

Does this indicate belts of different widths?

Should the belts ride flush with the outer edge of the pulley when new (not touching the base of the V groove), but as they wear, the move towards the centre of the pulley, hence the mule drive adjustment to take out slack?

 

Sorry, this is a lot, but it seems so difficult, and no one from Toro can give sound advice.

 

There are no stickers on the tractor except the C125 8 speed on the hood. I guess the old stickers have been "renovated" (painted over or removed).

 

 

the correct drive belt for the mower deck depends on the deck you are using .  Can you tell what deck you have  36 inch --  42 inch (Rear discharge or side discharge) or -- 48 inch

[Mr Greedy 0]

Ha ha, I was trying to add this info, but kept getting kicked out. Logged back in now!

 

It's a 36" rear discharge desk with 3 blades. I'll try and load some photos (keeps saying failed).

[Mr Greedy 0]

deck

[Mr Greedy 0]

tractor 

[gwest_ca-(File Mod) 11,096]

May not be the same deck model/year but the belts will be the same.

Click on the picture

 

[Mr Greedy 0]

Thank you very much for the link.

 

For the mower/deck/spindle belt, it recommends 1/2" × 76.94". The half inch width sounds right as this corresponds with the pulley width, but as mentioned in my post above, the existing (snapped) belt is about 80", and a new 79" belt is definitely too short to even install. I'm going to go with an 80" Conti to kevlar, RG4L800 as it's only £13 delivered.

 

For the PTO drive, the existing belt is 96", and I can try the recommended 102741 (1/2" × 96.9"), but the 96" I've taken off sits in the bottom of the pulley grooves, and is not that tight with the mule drive fully adjusted, hence the desire to change it. This might be helped with a new belt that is slightly wider, and that will therefore sit a little further out on the pulleys rather than sitting at the bottom of the groove like the old belt. What's particularly confusing me is that all the pulleys on the PTO system are 5/8" width at the outer circumference inside edge.

If I were to guess in the absence of any recommendations, I'd think it would be about 96" × 5/8" belt (Conti RG5L960).

 

I was also talking to my local Toro dealer trying to get to the bottom of this. They were sure that when belts are new, the back of the belt should be flush with the outer edge of the pulley (regardless of model), and therefore pulley width was a good give away. They also said the pulleys didn't look very worn (I took some with me).

 

On the belt profile, they said there is only about 5 profiles, but 3 are the common ones (3L, 4L and 5L). 

 

Can anyone with a C125 measure the width of their mower deck and PTO pulleys please? I guess it's  possible they have been changed on this tractor.

 

 

 

[gwest_ca-(File Mod) 11,096]

Have only seen a 5/8" belt used on a 60" deck if I remember correctly. And only one of them - the other was 1/2".

All others use 1/2" in both locations.

If you have a photo tachometer check the deck pulley rpm with the engine at full 3600 rpm. Blade tip speeds are not to exceed 19,200 feet per minute.

I suspect the blade length determines the pulley diameter to meet the specification but have never checked.

 

Look on the front of the blower housing behind the air cleaner for the Kohler spec number and serial number. May be able to identify the tractor model number from them.

 

Garry

[Mr Greedy 0]

I'll be away from the tractor for a couple of months, so the old man will get a couple of belts so I can experiment. We'll go with the 1/2" as that's what everyone's recommending, it's just odd that the PTO pulleys are all wider.

I'll report back with the findings in case anyone else needs help with their C125.

 

Managed to get a gearbox oil change done whilst I was there in the middle of storm Dennis 

God knows when that was last done!

Drain out choco milkshake. Fill with diesel. Drive around in 3rd for 15 minutes. Drain. Fill with decent gear oil. Drive for 15 mins. Drain again, and a final fill up with fresh oil. I'll probably do another change at the end of the summer, then every 100 hours as per the book.

[Mr Greedy 0]

Oh, and the Toro tech support got back after looking at the photos and asking a few questions, and they came to the same guess as everyone else.

102741 on the PTO and 8411 on the deck.

 

Just love these tractors. I wish I had the garden space to have one myself!

[peter lena 8,721]

WELCOME BILLYBOY !  seams like you are on track for your belt size , the glaring issue to me is the belt breaking ! , i have never broken a belt , without a doubt , you have a related bearing failure that is causing the issue. any part of the belt drive system should easily and smoothly turn over , no rough spots or galling. have you lubricated all related frictional and greased areas ? that 36 "r/d deck is the easiest running deck , there has got to be a bearing failure issue at some point. if you go over your entire belt drive set up and lubricate any motion / frictional point, from your pto lever , to your mule drive  , you can increase its  belt follow drive .let us know what you find out, pete