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We are completed stumped!
#1
R
Rock1956
R
Rock1956
We have a craftsman zts 7000 zero-turn mower. It is about 5 years old. About a month ago the left blade simply sheared off, leaving part of the bolt in the spindle. We have 6 acres that we keep mowed down, no stumps, no tall grass, nothing that you could run over. Because the bolt sheared off inside the spindle, we had to order the entire spindle assembly, PLUS the pulley on top because it is all attached. In other words, from top to bottom from the blade to the pulley. It cost us nearly $200 to buy every bolt, ring, spacer, spindle, pulley, etc. Now, this particular model of mower does not have a "star" on the spindle to insert the blade like most mowers do. Sears says it is just not built with one. We took the other side blade off and sure enough, that side is not that way and we have never had any trouble with that side coming off or shearing off. So we got the parts and put the mower back together. Mowed for about an hour and ... bamb, it sheared off exactly the same way. We started thinking maybe the bolts were defective. Contacted Sears and they were nice enough to send us the complete repair parts at no charge. Well, we got the parts, took it apart again and put it together again. Yesterday was the first time we used the mower since repairing it. It mowed for about an hour and bamb... seared off again exactly the same way. It makes no noise and simply (blade and bolt) drop to the ground. You don't even know it happens until you see your cut pattern. We are just going to trash the mower, but, we just can't understand why it is doing that. Anybody have any idea what might be going on?? Thank you.
#2
I
ILENGINE
I
ILENGINE
Could you please post the model number off of the tag. And possibly pictures of the broken bolt. Would like to get an idea what this thing looks like.
#3
R
Rock1956
I am enclosing pictures. The Operator's manual that we have says that the Model No. is 107.280063, but manual inside where you order the parts states that the model no. is 107.280062.View attachment mower.doc
I hope i have done that right. Thanks.
R
Rock1956
Could you please post the model number off of the tag. And possibly pictures of the broken bolt. Would like to get an idea what this thing looks like.
I am enclosing pictures. The Operator's manual that we have says that the Model No. is 107.280063, but manual inside where you order the parts states that the model no. is 107.280062.View attachment mower.doc
I hope i have done that right. Thanks.
#4
I
ILENGINE
I
ILENGINE
Just some speculation here. Since this is a Z turn, is it disengaging the blades every time you back up. then re engages when you go forward. I suspect this is happening when the blades re engage and torques the bolt. Possibly issue may be the shaft isn't fully seating in the blade mount for some reason allowing the bolt to have room to rotate tighter until you just snaps.
#5
R
Rock1956
Actually there has been no backing up during this time. I could mow nearly 1 hour, no backing, just going forward for the entire hour, and it shears off. the way this thing is put together, there just isn't any room for anything to be loose. You actually have to hold a wrench on one end (pully side) and use a ratchet to completely tighten. then switch sides and do it again. keep in mind, its three sets of this that have done the same exact thing. were you able to look at the pictures??
R
Rock1956
Just some speculation here. Since this is a Z turn, is it disengaging the blades every time you back up. then re engages when you go forward. I suspect this is happening when the blades re engage and torques the bolt. Possibly issue may be the shaft isn't fully seating in the blade mount for some reason allowing the bolt to have room to rotate tighter until you just snaps.
Actually there has been no backing up during this time. I could mow nearly 1 hour, no backing, just going forward for the entire hour, and it shears off. the way this thing is put together, there just isn't any room for anything to be loose. You actually have to hold a wrench on one end (pully side) and use a ratchet to completely tighten. then switch sides and do it again. keep in mind, its three sets of this that have done the same exact thing. were you able to look at the pictures??
#6
M
mechanic mark
M
mechanic mark
42" DECK-SPINDLE/IDLER Diagram & Parts List for Model 107280060 Craftsman-Parts Riding-Mower-Tractor-Parts | SearsPartsDirect Remove deck & inspect all parts for wear, idler pulleys & bearings, idler arm, as well as all hardware, check underside of deck also. When inspecting use hands on approach with parts & hardware checking for excessive movement of parts up & down, side to side. Let us know how it goes, thanks.
Does spindle have a grease fitting? If not I would disassemble, inspect bearings & grease by hand with a quality high temp grease.
Does spindle have a grease fitting? If not I would disassemble, inspect bearings & grease by hand with a quality high temp grease.
#8
L
logan01
Same here. Are you saying the shop is having you order a complete assembly each time? Hope not. Did you observe any stretch of the threads at the bolt break area? Only cause I can see is if either the blade is not making perfect contact or the spindle is not making perfect contact with the deck. You can try swapping left/right assemblies and see what happens.
L
logan01
When I try to open the file it shows corrupted and cannot be repaired.
Same here. Are you saying the shop is having you order a complete assembly each time? Hope not. Did you observe any stretch of the threads at the bolt break area? Only cause I can see is if either the blade is not making perfect contact or the spindle is not making perfect contact with the deck. You can try swapping left/right assemblies and see what happens.
#9
Homer1
Homer1
Are you torquing the blade to spec? Are the blades at any point coming in contact with one another, maybe wrong size blade. Have you replaced the blade on the spindle in question?
Not that you probably have done all 3 of these, but I have to ask. This situation sounds peculiar. I am doing some searching on info as I post this.
Also, along with inspection, check to make sure that something like a weld isn't loose under the deck possibly floating into the blade as it moves and wrecking the works. Like a baffle or etc, or a deck hanger hasn't broken allowing the deck to float or rock lower than you expect it to be.
Not that you probably have done all 3 of these, but I have to ask. This situation sounds peculiar. I am doing some searching on info as I post this.
Also, along with inspection, check to make sure that something like a weld isn't loose under the deck possibly floating into the blade as it moves and wrecking the works. Like a baffle or etc, or a deck hanger hasn't broken allowing the deck to float or rock lower than you expect it to be.
#10
R
Rock1956
See we thought the same thing... something has got to be stopping the blade while the spindle is still moving until it shears off. We can't find any damage, we buy the blades using the part no. supplied by sears and there is no bending or damage on the blades. And yes, we have to order the complete assembly from pulley down to the blade. It cost us about $200.00. Sears replaced it the next time for free, but, it sheared again. The bolt shears halfway into the end of the spindle so you can't get it out in order to undo the screw at the other end where the pulley is. I know that we could take it to a shop and have them dig the bolt out, but if we can't figure out why it is happening there is no sense doing it. We took the other side off just to see if there was something being done different and put it back together and have no problem with that side at all, so we felt we were putting it back correctly. We even greased it thru the portals thinking maybe it was heating up and shearing. I keep trying to download the pictures thru this system and it keeps telling me the size is too large and I don't know how i could make it smaller. If you have a different email address i could send them for you to look at.
R
Rock1956
Are you torquing the blade to spec? Are the blades at any point coming in contact with one another, maybe wrong size blade. Have you replaced the blade on the spindle in question?
Not that you probably have done all 3 of these, but I have to ask. This situation sounds peculiar. I am doing some searching on info as I post this.
Also, along with inspection, check to make sure that something like a weld isn't loose under the deck possibly floating into the blade as it moves and wrecking the works. Like a baffle or etc, or a deck hanger hasn't broken allowing the deck to float or rock lower than you expect it to be.
See we thought the same thing... something has got to be stopping the blade while the spindle is still moving until it shears off. We can't find any damage, we buy the blades using the part no. supplied by sears and there is no bending or damage on the blades. And yes, we have to order the complete assembly from pulley down to the blade. It cost us about $200.00. Sears replaced it the next time for free, but, it sheared again. The bolt shears halfway into the end of the spindle so you can't get it out in order to undo the screw at the other end where the pulley is. I know that we could take it to a shop and have them dig the bolt out, but if we can't figure out why it is happening there is no sense doing it. We took the other side off just to see if there was something being done different and put it back together and have no problem with that side at all, so we felt we were putting it back correctly. We even greased it thru the portals thinking maybe it was heating up and shearing. I keep trying to download the pictures thru this system and it keeps telling me the size is too large and I don't know how i could make it smaller. If you have a different email address i could send them for you to look at.
#11
M
motoman
M
motoman
The responders in this thread are on the right track IMO. We do need closeup pics of the sheared bolt halves. Are there any circular marks on the blade clamp area which might indicate looseness which could lead to over heat and annealling (softening) of the bolt? Any purple or brow color on the blade in that area? Or overheating and shock hardening (embrittling) of the bold on cool down or perhaps water is being used to clean the deck and "quenches" an over heated bolt? If the bolts being furnished are a bit long or somehow the new bolt housing is under bored (depth) you could be torquing against this abutment when you think you are properly stretching the bolt. Try making some depth measurements with a caliper vs length measurement of the old and new bolts. And , though doubtful if the bolts are OEM, there have been many bootlegged low tensile bolts smuggled into to this country . Legititmate bolt head markings can be found that will identify the factory and also the grade.
Perhaps more info than you wanted??:laughing:
Buy a blue marker pen and take a reading of the bolt bearing surface after torquing . Both it and its mating surface should show contact. Do this also to the tip of the bolt.
Kept thinking ...if you use a lubricant like anti seize and do not reduce the required torque by up to 40% you could be causing the bolt to yield (stretch too far). There is a chart in this forum showing the lubricants and reduction factors.
Perhaps more info than you wanted??:laughing:
Buy a blue marker pen and take a reading of the bolt bearing surface after torquing . Both it and its mating surface should show contact. Do this also to the tip of the bolt.
Kept thinking ...if you use a lubricant like anti seize and do not reduce the required torque by up to 40% you could be causing the bolt to yield (stretch too far). There is a chart in this forum showing the lubricants and reduction factors.
#12
RoperGuy
RoperGuy
If you still have your old spindle assembly, you should try too drill out the stud and threads, use a tap and cut threads for the next size up bolt, go to a place like fastenal or brafasco and get your self a higher grade bolt. It's a free test anyways.
#13
Homer1
Homer1
As for pictures, try to sign up for a free Photobucket account or similar, then upload your pictures there, and you can link the pictures here on the forum for us to see. You can use the "img" link and paste it directly into a post once hosted, and it should just pop up as a picture here. If not, you will still be pasting a link that we can click on to see it.
Really an odd problem, I'm sure we'd all like to see you get it figured out fast!
Really an odd problem, I'm sure we'd all like to see you get it figured out fast!
#14
R
Rock1956
R
Rock1956
<iframe width="480" height="360" src="http://s989.photobucket.com/user/lisa_carnell1/embed/slideshow/"></iframe>
see if this works for the pictures
see if this works for the pictures
#15
R
Rock1956
lisa_carnell1's Library | Photobucket
R
Rock1956
As for pictures, try to sign up for a free Photobucket account or similar, then upload your pictures there, and you can link the pictures here on the forum for us to see. You can use the "img" link and paste it directly into a post once hosted, and it should just pop up as a picture here. If not, you will still be pasting a link that we can click on to see it.
Really an odd problem, I'm sure we'd all like to see you get it figured out fast!
lisa_carnell1's Library | Photobucket
#16
L
logan01
L
logan01
The only reasonable problem I can come up with is, assuming the bolts are good, is that you are torqueing them too tightly. Are you using an impact wrench? If so, do you have an idea as to lbs? For grins, I would find a way to remove one of the broken bolts, cleanup the bottom of the spindle, purchase a grade 8 or stronger bolt. If possible, even if it requires cutting, I would use a bolt that is a solid 1/8" shorter than the factory bolt just in case the factory length, for whatever reason, is bottom out thus putting stress somewhere along the bolt. Instead of cutting, you might be able to use a washer or two on the outside of the blade.
#17
M
motoman
M
motoman
Picture suggests work hardening or over torque IMO. (Looseness and repeated bending or torquing beyond the yield point. ) The pictures help, but even the picture of the head portion break- off would help also (the other half). I'm guessing lubricant and unlubricated torquing force or air wrench and lubricant and just tightening by judgement (over torque). But if all 3 were treated similarly it is a puzzle.:2cents:
#18
D
DaveTN
D
DaveTN
Someone earlier mentioned swapping out the other spindle/pulley assembly and
see if it wrings the bolt in two on that one. If so, then it would have to be something
only on that one side of the deck causing the bolt to shear or wring in two pieces. If
the bolt is a high enough grade to resist shearing, then it has to be something in the
torque being too much, or something misaligned causing the shear force. I might try
swapping out one from the other side of the deck to see if it wrings in two or not; But
I would hate to see it shear that one as well. Odd that it only affects that one side.
Also it is shearing down in the shaft and not just the top portion at the top of the pullsy.
I have seen shafts wring off at the blade but this is not the case either. :confused2:
see if it wrings the bolt in two on that one. If so, then it would have to be something
only on that one side of the deck causing the bolt to shear or wring in two pieces. If
the bolt is a high enough grade to resist shearing, then it has to be something in the
torque being too much, or something misaligned causing the shear force. I might try
swapping out one from the other side of the deck to see if it wrings in two or not; But
I would hate to see it shear that one as well. Odd that it only affects that one side.
Also it is shearing down in the shaft and not just the top portion at the top of the pullsy.
I have seen shafts wring off at the blade but this is not the case either. :confused2:
#19
M
mechanic mark
M
mechanic mark
Purchase a left handed cobalt or titanium drill bit to remove broken bolts, after locking bit in chuck place drill in reverse, drill slowly & spray bit with oil every minute or two to keep bit cooled down. Purchase two grade 8 bolts of same size to fit, purchase a small pack of antiseize compound & put on bolt threads, torque bolts with torque wrench to specs., grease spindles.
#20
B
bertsmobile1
B
bertsmobile1
With the Metalurgists hat on and allowing for the quality of the images, that looks pretty much like a strait torsional brittle shear fracture.
So as per previous posts, try some grade 8 or better bolts.
Measure the depth of the bolt hole very carefully.
I have a sneaky suspicion that your spindle hole might be a bit too shallow or the spindle blade assembly is missing a spacer so the bolt is bottoming out in the hole.
The act of mowing tightens up the spindle bolt and my guess is your bolt is bottomed out then gets more torque from the blades so snap.
Specified torques are always for a clean dry thread unless otherwise instructed.
Lubrication can cause drastic over tightening.
If both the top nut & bottom bolt were lubricated then you can be drastically over tightening the whole system.
So as per previous posts, try some grade 8 or better bolts.
Measure the depth of the bolt hole very carefully.
I have a sneaky suspicion that your spindle hole might be a bit too shallow or the spindle blade assembly is missing a spacer so the bolt is bottoming out in the hole.
The act of mowing tightens up the spindle bolt and my guess is your bolt is bottomed out then gets more torque from the blades so snap.
Specified torques are always for a clean dry thread unless otherwise instructed.
Lubrication can cause drastic over tightening.
If both the top nut & bottom bolt were lubricated then you can be drastically over tightening the whole system.
#21
Homer1
Homer1
This sounds like a good start.
I forgot to ask, did this start just at random, or was it after a sharpening or blade change? You may have mentioned it but I didn't see it. If it's never happen before a change or removal then stands to reason something has obviously changed.
May try to hang torque the blade using a torque wrench and blade buddy or something to secure the blades while tightening, just to be 100% sure it's to spec. Torque wrenches can over torque fast.
I forgot to ask, did this start just at random, or was it after a sharpening or blade change? You may have mentioned it but I didn't see it. If it's never happen before a change or removal then stands to reason something has obviously changed.
May try to hang torque the blade using a torque wrench and blade buddy or something to secure the blades while tightening, just to be 100% sure it's to spec. Torque wrenches can over torque fast.
#22
R
Rock1956
We finally figured it out! You know we kept asking SEARS why they were selling us star blades when the spindle screw was round an they kept saying that is just the way it was. We questioned why there wasn't a star bolt to put the star blade. Well, come to find out they were totally wrong. What was happening was as the blade spun around and around the round screw part of the spindle would start wearing down the insides of the star which gave it leeway to shift back and forth and this particular blade that kept shearing would be able to move enough to start catching the inside of the metal opening where the cut grass went out. It would keep hitting and hitting til a slither on the blade produced would completely catch the metal and STOP the blade, with the spindle still spinning 90mph it would shear. When we took the other blade off on the other side, the inside of the "star" was completely worn smooth giving it room to move too, only there wasn't an opening for the blade to catch like there was on the other side. When we went to sear again to buy blades, we took the book with us, the blades they brought us were not the same number and we showed them, they said, they will work, they are the same size. We said NO we want the ones with same PART NUMBER as shown in the book. They went back and brought us blades with the same PART NUMBER. Guess what, they were NOT STAR blades!!! Simple as that.... $600 in repair parts later. We have been mowing for a week straight and no problem. We had just bought this mower from my brother and knew he had never had problems with it before. We talked to him and he mentioned that when we bought it, the day before we picked it up, he went to Sears and bought a new belt and blades and replaced them so they would be new when we picked it up. Trying to be nice (smile). Sears sold him the "star" blades. Anyways, thanks for all your help! If this ever comes up again, just be adament with Dealers... you don't put a "star" blade on a "round" spindle. I don't care how many times they say "that is how they are constructed."
R
Rock1956
This sounds like a good start.
I forgot to ask, did this start just at random, or was it after a sharpening or blade change? You may have mentioned it but I didn't see it. If it's never happen before a change or removal then stands to reason something has obviously changed.
May try to hang torque the blade using a torque wrench and blade buddy or something to secure the blades while tightening, just to be 100% sure it's to spec. Torque wrenches can over torque fast.
We finally figured it out! You know we kept asking SEARS why they were selling us star blades when the spindle screw was round an they kept saying that is just the way it was. We questioned why there wasn't a star bolt to put the star blade. Well, come to find out they were totally wrong. What was happening was as the blade spun around and around the round screw part of the spindle would start wearing down the insides of the star which gave it leeway to shift back and forth and this particular blade that kept shearing would be able to move enough to start catching the inside of the metal opening where the cut grass went out. It would keep hitting and hitting til a slither on the blade produced would completely catch the metal and STOP the blade, with the spindle still spinning 90mph it would shear. When we took the other blade off on the other side, the inside of the "star" was completely worn smooth giving it room to move too, only there wasn't an opening for the blade to catch like there was on the other side. When we went to sear again to buy blades, we took the book with us, the blades they brought us were not the same number and we showed them, they said, they will work, they are the same size. We said NO we want the ones with same PART NUMBER as shown in the book. They went back and brought us blades with the same PART NUMBER. Guess what, they were NOT STAR blades!!! Simple as that.... $600 in repair parts later. We have been mowing for a week straight and no problem. We had just bought this mower from my brother and knew he had never had problems with it before. We talked to him and he mentioned that when we bought it, the day before we picked it up, he went to Sears and bought a new belt and blades and replaced them so they would be new when we picked it up. Trying to be nice (smile). Sears sold him the "star" blades. Anyways, thanks for all your help! If this ever comes up again, just be adament with Dealers... you don't put a "star" blade on a "round" spindle. I don't care how many times they say "that is how they are constructed."
#24
L
logan01
L
logan01
Good deal. Guess I didn't know you were trying to install the star type blades on a non-star spindle. Pretty obvious in the Sears diagram. 42" DECK-SPINDLE/IDLER Diagram & Parts List for Model 107280060 Craftsman-Parts Riding-Mower-Tractor-Parts | SearsPartsDirect
#25
R
Rock1956
R
Rock1956
that is what we kept telling Sears when they kept selling us those blades. They just kept saying "that is how it is constructed"....
#26
R
Rock1956
no actually no vibration noticed, you would mow for about 1 hour and it would just "fall off" ..............
R
Rock1956
Glad you figured it out. But the vibration must have been really bad, yet no mention?
no actually no vibration noticed, you would mow for about 1 hour and it would just "fall off" ..............
#27
L
logan01
L
logan01
Guess that's been our new norm for a while. Zero knowledge at the larger retailers. Glad you got it squared away,