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Discussion Starter · #1 ·
I have a 1992 Sears 917 series 42" ride on lawn tractor.
When I took my foot off the brake/clutch, it would stay down so I'd have put my foot under the pedal to get going. last week the drive belt broke so I assumed that had been the problem. I have just replaced the belt; the pedal releases ok but snatches badly and moves off with a jolt. Any suggestions to fix this please?
 

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Discussion Starter · #7 ·
if its a brand new belt sometimes you have to let them brake in a little as some are tight needs to stretch a little
Maybe but I have a feeling that it isn't taking up the slack in belt slowly enough, maybe something needs freeing or the spring isn't moving smoothly. I'l better weather the humidity and have another look
 

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Well if I can't see anything obvious I'll take you very welcome advise.

Many thanks to you both for responding.
First of all, make sure you have the proper belt. An automotive belt is not the proper belt. You need an "agriculture" or "outdoor equipment belt" which is designed for clutching operations. That type of belt is designed for engaging and disengaging traction by means of tensioning or untensioning the belt using movable idler pullies. They are very strong and reinforced with kevlar. Tractor Supply Co. and Grainger, among others, carry these types of belts.

Next, make sure you have the correct size of belt. That includes both length and cross-sectional size (width and depth).

Make sure that all moving parts of the drive system are free to rotate and move as designed. Typically, you will find that some of these parts may need lubrication (grease fittings, or a drop of oil on a pivoting part) to keep it from resisting "arrest".

Idler clutching pullies work by moving them in one direction by stepping on a pedal and by stepping off that pedal to allow them to return to the engaged position. For that to work properly, there is a return spring and that spring provides all of the clutching force. Make sure it is intact, properly installed, and appears not to be stretched or damaged in any way Also, double check the linkage from pedal to idler to make sure it isn't sticking during any part of its range of motion. You should not only check this manually, but by sitting down in your normal operating position and pressing the pedal in and releasing it just as if you were mowing.

Hope this helps!
 

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is there a clutch spring????
Typically, especially for pedal-controlled clutching, you push the pedal down to unclutch. You step off the pedal to engage the clutch. In that engaged position, there must be a force to maintain the proper pressure of engagement of the belt and the idler pulley, which force determines the belt tension.

That force is usually provided by a spring. I suppose you could have a notch for lever actuated clutches, but proper operation would be greatly affected by belt stretching and wear and you wouldn't be able to keep it properly adjusted to prevent over-stressing the belt or under-tensioning it, resulting in drive slippage.

My GTV 11 has such a lever, with notches to lock it into the engaged or disengaged positions, but the mower drive belt is tensioned by a spring anyway.

The motion drive belt is also tensioned by a spring on the clutching idler (actually it's the secondary motion drive belt that's directly affected and it couples the tension into the primary belt thru the vari-drive unit).

Many years ago, my motion belt idler spring failed when one of its two hooked ends just broke off. I was able to bend a new hook in that end, which, of course, shortened the belt. I then added a link (as I recall, I think I bent one out of a nail!) to get back to the original length. It's been fine ever since. I think the motion of that hook on the attachment point caused it to wear and break--the extension is much more rugged (it's a fat nail!) so it hasn't been a problem again.
 

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Discussion Starter · #13 ·
First of all, make sure you have the proper belt. An automotive belt is not the proper belt. You need an "agriculture" or "outdoor equipment belt" which is designed for clutching operations. That type of belt is designed for engaging and disengaging traction by means of tensioning or untensioning the belt using movable idler pullies. They are very strong and reinforced with kevlar. Tractor Supply Co. and Grainger, among others, carry these types of belts.

Next, make sure you have the correct size of belt. That includes both length and cross-sectional size (width and depth).

Make sure that all moving parts of the drive system are free to rotate and move as designed. Typically, you will find that some of these parts may need lubrication (grease fittings, or a drop of oil on a pivoting part) to keep it from resisting "arrest".

Idler clutching pullies work by moving them in one direction by stepping on a pedal and by stepping off that pedal to allow them to return to the engaged position. For that to work properly, there is a return spring and that spring provides all of the clutching force. Make sure it is intact, properly installed, and appears not to be stretched or damaged in any way Also, double check the linkage from pedal to idler to make sure it isn't sticking during any part of its range of motion. You should not only check this manually, but by sitting down in your normal operating position and pressing the pedal in and releasing it just as if you were mowing.

Hope this helps!
Thanks for all that JH,

The belt is brand new from Sears, I have the manual and was able to check the correct part number.
Before I replaced the deck I put grease on all the moving parts of the clutch/brake coupling. I then reassemble the deck, twice actually because the clutch rod facing the wrong way after I had all the other parts in place:fing20:
Just finished mowing an acre and it now works really well, apart from the grass length and I'd better start a new thread for that.

Once again thank you and I really appreciate your help.
 

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Well maybe I missed it already above but you say this is a clutch/brake, perhaps you need to back off on the brake adjustment a little. Sounds to me like the clutch/belt is already engaging pretty forcefully before the brake releases.

Walt Conner
 
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