Topper - Shear Bolt breakage

[Patrick brian]

My new tractor to me is a case cx90 but when I put on the Fleming topper and have pto at 540 it breaks the shear bolt which are 10.9x8mm bolts do I get a stronger bolt are is there something wrong with my tractor it can work the slurry tanker and the side cast dung spreader without any problems can anyone help

 

[balerman]

Are you trying to start it at 540 pto revs,if so that is why the bolt is breaking.Start it at much lower revs.

 

[Tim G]

Replace the shaft on topper for one with a slip clutch?

 

[RS1600BDA]

As said, start on tick over and with the topper lifted of the ground build up the speed and lower.
It shouldn’t break a shear bolt unless it’s under a great load.

 

[Ffermer Bach]

if I drop the pto in too sharply it breaks the shear bolt

 

[Patrick brian]

Are you trying to start it at 540 pto revs,if so that is why the bolt is breaking.Start it at much lower revs.

The tractor is just ticking over

 

[del_boy]

The tractor is just ticking over

Some tractors are very harsh on pto start up, our early t7 nh was terrible, had to put a laptop on it to delay it which was an improvement.
Try turning the pto on then straight back off again then on again and see if that helps. No idea why but it did help our nh
Replacing the shear bolt pto for a slip clutch kind might be the best option

 

[Mur Huwcun]

Technically a slip clutch and a shear bolt don’t protect the machine the same. A slip clutch is for overloading while a shear bolt shears under impact, eg a blade topper hitting a stone, with a slip clutch it would only slow down if enough strain was put on the blade by for example cutting heavy rushes.

Back to the op, the PTO is engaging to fierce, no idea how to adjust them on a CX as it’s essentially an IH 574 from the 70s with an MCV block but the spool is operated hydraulically from an electric switch rather than a linkage to the spool on the MCV. On some tractors you can get away with it by letting the clutch go at exactly same time as you engage PTO and the strain of moving off will dip the revs enough to start up without shearing the shear bolt

 

[Tractorstant]

Don't ask me the technicalities, but sold a number of bogo Case JX's and the PTO was so harsh on the engagement it would snap sheer bolts like a carrot. one trick was to start the tractor with the pto engaged ( if this is possible ). Feathering in the PTO was almost impossible. Once the topper blade is spinning and you have some momentum you'll be fine.

 

[jackp]

Technically a slip clutch and a shear bolt don’t protect the machine the same. A slip clutch is for overloading while a shear bolt shears under impact, eg a blade topper hitting a stone, with a slip clutch it would only slow down if enough strain was put on the blade by for example cutting heavy rushes.

Back to the op, the PTO is engaging to fierce, no idea how to adjust them on a CX as it’s essentially an IH 574 from the 70s with an MCV block but the spool is operated hydraulically from an electric switch rather than a linkage to the spool on the MCV. On some tractors you can get away with it by letting the clutch go at exactly same time as you engage PTO and the strain of moving off will dip the revs enough to start up without shearing the shear bolt

I thought a CX90 would still have manual engagement of the PTO just like the older ones

 

[Mur Huwcun]

I thought a CX90 would still have manual engagement of the PTO just like the older ones

Possibly, is it the 95 that’s not then?

If it’s manual and I think you’re right (yellow handle?) then it should feather in

 

[Ffermer Bach]

Technically a slip clutch and a shear bolt don’t protect the machine the same. A slip clutch is for overloading while a shear bolt shears under impact, eg a blade topper hitting a stone, with a slip clutch it would only slow down if enough strain was put on the blade by for example cutting heavy rushes.

Back to the op, the PTO is engaging to fierce, no idea how to adjust them on a CX as it’s essentially an IH 574 from the 70s with an MCV block but the spool is operated hydraulically from an electric switch rather than a linkage to the spool on the MCV. On some tractors you can get away with it by letting the clutch go at exactly same time as you engage PTO and the strain of moving off will dip the revs enough to start up without shearing the shear bolt

I am presuming you can't start the tractor with the PTO in gear? The would solve the problem of too quick an engagement.

 

[bobk]

Set the revs to cut the grass nicely , 540 at the pto isn't mandatory

 

[Werzle]

Use high tensile bolts and do them up tight. If the bolt is slack in the hole and/ or the pto yokes have to much play it aids the snatch when you engage and snaps the bolts

 

[Barleymow]

Sounds like you need someone to spin the blades as you start up ,but like an old aeroplane .

 

[Wellytrack]

Sounds like you need someone to spin the blades as you start up ,but like an old aeroplane .

'Elf n safety says no. What your saying makes sense and will likely help. Similar to starting off heavy stuff in landrive PTO.

Still wouldn't ask someone to stand near a spinning flailing thing with blades though.

 

[Barleymow]

'Elf n safety says no. What your saying makes sense and will likely help. Similar to starting off heavy stuff in landrive PTO.

Still wouldn't ask someone to stand near a spinning flailing thing with blades though.

It was written in jest

 

[7610 super q]

There's an old thread on here somewhere about the very same. I even remember pointing out that old classics had levers which you could feather in.
Drop the revs as low as possible is all you can do. That or an oversize WalterP type shearbolt.......

 

[Bluetree]

Ford 7840 when cold will break shearpins on the strawchopper when turning the pto on at tickover, turn engine revs up to about 1400rpm and its a lot smoother, ok when she's warm.

 

[Wellytrack]

'Elf n safety says no. What your saying makes sense and will likely help. Similar to starting off heavy stuff in landrive PTO.

Still wouldn't ask someone to stand near a spinning flailing thing with blades though.

You would be surprised. It has happened.