149 rock shaft question

[Mike Reed]

I can't seem to get full lift on the lift arm, the inside of the rock shaft both deck lifts lift all the way and level. The lift arm starts with the hydraulics, but at a certain point stops turning. I have a Johnny Bucket, Jr (custom made 20 years ago), could it be the weight? I don't know the inner workings to understand the slippage. I took out the roll pin and installed a grade 8 bolt to test, does the same thing.

 

[mgwin]

Use a coiled spring pin instead of a bolt or roll pin.
Not 100% sure at this moment, but I think there is more than one coiled spring pin in there somewhere. You could also check the deck linkages, and mule drive for wear.

 

[IHinIN]

There are 3 spirol pins. One on the left deck lift arm, one on the right deck lift/ cylinder attachment arm, and one on the height stop/ front blade lift rod attachment arm on the right side of the frame. I had one of the pins partially shear and the blade would barely lift off the ground. I ditched the pins and made a new rock shaft with 1/4” key ways and broached keys in all three arms.

 

[Mike Reed]

There are 3 spirol pins. One on the left deck lift arm, one on the right deck lift/ cylinder attachment arm, and one on the height stop/ front blade lift rod attachment arm on the right side of the frame. I had one of the pins partially shear and the blade would barely lift off the ground. I ditched the pins and made a new rock shaft with 1/4” key ways and broached keys in all three arms.

Thanks, @IHinIN . I didn't mess with the left side, as it seems to go perfectly with the right side deck lift that has the hydraulic cylinder attached. When I lift it, the outer (to the bucket), it glides perfectly 70% of the way, then doesn't conform with the rest of the shaft. I don't have the deck height setter in the way, I can't believe I could have broken a grade 8 bolt, but maybe I had. I didn't drive it out to check, as the lift keeps doing the same thing. When I drove in two 5/16 sheer pins, the two broke when lowered it abruptly. At first it raised very high. I don't have a lift rod, I've been using a 1-inch strap as it has the strength to lift, just no down pressure, but hasn't been a problem. I know I'm missing something, but I can't figure it out.

 

[dschwandt]

Sounds as if the rock shaft proper is twisted but that is doubtfull as it is a 3/4" shaft. Unless it is severely worn where the mower center frame ass'y fork rides on it.
Are both the lift arms, part #18 &19 in alignment?
Something must be binding somewhere and should be readily evident when observing operation of the lift

 

[jdrong]

I had the same problem several years ago. My mower deck lifted higher on one side than the other and didn't have enough up and down travel, same with the snow thrower. I finally discovered the problem to be that all the spirol pin holes in items # 17, 18, and 19 were slightly worn. In this case a slight wear makes a big difference at the attachment. Take the cover off and run the hydraulics up and down a few times to see how far the cylinder moves before an attachment moves.

 

[dschwandt]

A shear pin will break, it's supposed to, that's why it's called a shear pin.
It breaks before something really important breaks.
The fact that it broke should be telling you something.
How heavy is this bucket? Are you ramming it against something trying to break something loose or lifting or dropping something too heavy inducing undue shock to the unit?
Do you have a lockout pin in the system for down pressure or is the built in lift mode for play still in use?.
Without the lockout pin in place, part #23, it will allow only so much lift before bottoming out and when/if it does, depending on what you are doing at the time, all bets are off.

 

[-CӞ]

A shear pin will break, it's supposed to, that's why it's called a shear pin.
It breaks before something really important breaks.
The fact that it broke should be telling you something.
How heavy is this bucket? Are you ramming it against something trying to break something loose or lifting or dropping something too heavy inducing undue shock to the unit?
Do you have a lockout pin in the system for down pressure or is the built in lift mode for play still in use?.
Without the lockout pin in place, part #23, it will allow only so much lift before bottoming out and when/if it does, depending on what you are doing at the time, all bets are off.

≈ pressure relief valve