Sheared hydraulic shaft on sk800

Serf Life

Carpal tunnel level member
Location
Maine Island
Sk800 with about 450 hrs. On turf with no kicked up rocks and a very modest grapple of brush. It is the right side with the parking brake pin, curious if that played a part in cycles to failure. Also just replaced the rear hub assembly on that side. Replacement is on the way. Anyone shear these and at what hours? 182C86E3-001A-47F8-A8BB-E7E0C3EF67AB.png AEF3F073-1775-4EE2-86AC-6DC50E330AC6.jpeg
 

evo

Been here a while
Location
My Island, WA
Sk800 with about 450 hrs. On turf with no kicked up rocks and a very modest grapple of brush. It is the right side with the parking brake pin, curious if that played a part in cycles to failure. Also just replaced the rear hub assembly on that side. Replacement is on the way. Anyone shear these and at what hours? View attachment 78374 View attachment 78375
Looking at the photo there is a flaw going from almost center to 3 o’clock in the steel. From about noon to 11 o’clock is a older crack that formed

It was a matter of time, you ca. See about 10 o’clock or if we were looking at a stump/ cross cut the “pith” is about there. I can’t see if the stress crack in that location is due to the failure or part of the cause.
 

Sfoppema

Participating member
Location
Central MA
I've had it happen on my 1050 both sides before 1000 hours. It is a common issue with the 800 and 1050. Ditchwitch has an upgrade for it as they are aware of the issue. Jesco offered to do it for free for me, said it was a two day project. I'm 6 months out of warranty. Pretty stoked about the customer service. Haven't made the time to drop it off yet.

If you aren't going to do the upgrade, I would suggest buying two of those, because the other one isn't going to be too far behind. That is what I did. When the second one broke it only took 20 minutes to replace, I had it in the truck... It's a quick swap.
 

Serf Life

Carpal tunnel level member
Location
Maine Island
This is a problem with sk800s. Seen people post this repeatedly on Facebook in some of the mini skid groups.
Seems crazy for so few hours. It takes substantial strain though. I have noticed that the brake pin often sticks at startup which would lead to part of the strain. It automatically engages when the engine goes off and is supposed to disengage at startup but can catch on one of the sprocket-break-notches.
 

Serf Life

Carpal tunnel level member
Location
Maine Island
Doesn’t help that the machine is broke down right infront of a mountain of stacked trees offshore. And I was like “chipper is off the barge, big skidsteer got it up the beach and hill to the jobsite, mini got to the island after unsticking the barge. Whew, stress has diminished!” ……….fuuuuuuuck 6B8741BE-CA80-4B25-8C0B-15876206A40C.jpeg
 

Sfoppema

Participating member
Location
Central MA
Doesn’t help that the machine is broke down right infront of a mountain of stacked trees offshore. And I was like “chipper is off the barge, big skidsteer got it up the beach and hill to the jobsite, mini got to the island after unsticking the barge. Whew, stress has diminished!” ……….fuuuuuuuck View attachment 78382
Wow that's inconvenient. All the more reason to have an extra in the truck... sharp chipper! At least it's a nice view....
 

Serf Life

Carpal tunnel level member
Location
Maine Island
Update. Getting the busted shaft out of the sprocket assembly needed a hydraulic press, it sounded like a rifle shot when it came free. So damn loud.

The keyway on the sprocket side needed some filing for the new hyd motor shaft to seat. No biggy but I’d recommend folks check all the fit and finish before heading to the machine. The install itself is very easy as @Sfoppema said. Guessing a cup or less of hyd fluid leaked out during the swap. Mark the hyd fittings before removal if not marked already.

Nut is seated to 350 ft lbs on shaft and trailer nuts on the sprocket are 110 ft lbs. Hope this helps others in the future.
 

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