Maximum cylinder extension?

[houser52]

I put a Kubota SSQA on my Kubota LA680 loader last year. Kubota didn't offer a SSQA to fit my loader but one that fit another model fit without any major mods. The only downside to the install was that I lost some of the dump angle but the rollback angle is great. I'm thinking about moving the bucket stops on the loader to give me a little more dump. It's not a problem when dumping low to the ground but with the loader raised over half way, I can't get a full dump.

At full dump the cylinders don't look to be extending far enough so, my plan is to remove the SSQA and slowly extend the dump cylinders until they stop. Then reposition the bucket stops to where they are just shy of the cylinders being fully extended.

Am I going about this the right way? How much clearance should there be inside the cylinder to keep them from over extending?

 

[Jabonee]

You may want to check the parts breakdown for the cylinder. Some have a sleeve on them to prevent the piston from hitting end cap. :thumbsup:

 

[houser52]

You may want to check the parts breakdown for the cylinder. Some have a sleeve on them to prevent the piston from hitting end cap. :thumbsup:

There is no sleeve or anything on the outside to limit travel.

 

[Jabonee]

There is no sleeve or anything on the outside to limit travel.

Yes I was referring to the inside.:thumbsup:

 

[Xfaxman]

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​You may have lost some dump angle when you converted to SSQA due to slightly different pin spacing's.

At full dump the cylinders don't look to be extending far enough so, my plan is to remove the SSQA and slowly extend the dump cylinders until they stop. Then reposition the bucket stops to where they are just shy of the cylinders being fully extended.

Am I going about this the right way? I would do max dump, pull the rod pins, extend full and see how much more travel there is. Then grind away the stops a little at a time, checking the clearance noted below.

How much clearance should there be inside the cylinder to keep them from over extending?

I have never heard of "over extending" a cylinder.

The bucket stops are there to prevent the extended cylinder from hitting the loader arm and bending the rod.
My loader doesn't have bucket stops, it stops extending when the piston hits the end of the cylinder.

Note the clearance where the arrow points, between the rod end of the cylinder and the loader arm.

The clearance is different, depending on the pivot pin to rod pin spacing.

 

[houser52]

Yes I was referring to the inside.:thumbsup:

I looked at Messick's diagram of my cylinder. It shows and lists the piston, head and o-rings inside but no description or pics of a sleeve.

 

[houser52]

I have never heard of "over extending" a cylinder.

The bucket stops are there to prevent the extended cylinder from hitting the loader arm and bending the rod.
My loader doesn't have bucket stops, it stops extending when the piston hits the end of the cylinder.

Note the clearance where the arrow points, between the rod end of the cylinder and the loader arm.

The clearance is different, depending on the pivot pin to rod pin spacing.

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Thanks for the info. I was concerned about messing up something inside the cylinder. When fully extended now, I have a good bit of room between the cylinder and the boom. I doubt it would make contact before the cylinder stopped.

If it won't hurt the cylinder I might just cut off the stops and leave it like that. Thoughts?

 

[4570Man]

Unbolt the cylinder rod from the SSQA plate and see how far it can extend past its current travel. I'd bet not much.

 

[Xfaxman]

Thanks for the info. I was concerned about messing up something inside the cylinder. When fully extended now, I have a good bit of room between the cylinder and the boom. I doubt it would make contact before the cylinder stopped.

If it won't hurt the cylinder I might just cut off the stops and leave it like that. Thoughts?

I don't know why Kubota uses them? Maybe manufacturing tolerances and cylinder differences.

I also don't know the differences in pin hole spacing between your original bucket and The new SSQA.

If the bucket holes were farther apart, the cylinder would have been closer to the arm.

 

[houser52]

I don't know why Kubota uses them? Maybe manufacturing tolerances and cylinder differences.

I also don't know the differences in pin hole spacing between your original bucket and The new SSQA.

If the bucket holes were farther apart, the cylinder would have been closer to the arm.

The holes on the new SSQA is 1/4" farther apart than the holes on the original bucket.

 

[LD1]

I think the plan of attack is correct as long as the cylinders don't hit the loader arms, and you do put the mechanical stops back on.

The cylinder won't destroy itself under hydraulic power even if hard stops are not put back on. The issue is outside forces. Like bucked dumped all the way and jsi g the cutting edge like a bulldozer.... Or dumping a heavy load with inertia and sitting full extend hard. The mechanical stops keep the piston from busting the rod cap off the cylinder

 

[4570Man]

It won't hurt the cylinder to bottom out. The lift cylinders very likely bottom out and my curl cylinders bottom out when curling up.

 

[Leejohn]

The stops are there to help to clean the bucket.

 

[LD1]

Bottoming out when curling up isn't a big deal. It's bottoming out when extending, then applying additional outside force trying to tear the cylinder apart

 

[houser52]

I appreciate all the useful info so far. Sounds like it's not as big of a concern as I thought it was.

 

[Jabonee]

I looked at Messick's diagram of my cylinder. It shows and lists the piston, head and o-rings inside but no description or pics of a sleeve.

OK sounds like your cylinders do not have internal stop. So you need to manuely determin max extension. Pull pin on bucket end. disconnect hoses. (Messy,Careful) pull rod out and measure. Careful if you decide to modify stops. You can get too much roll and throw the geometry off causing the bucket to bind and not roll back. :thumbsup:

 

[Xfaxman]

OK sounds like your cylinders do not have internal stop. So you need to manuely determin max extension. Pull pin on bucket end. disconnect hoses. (Messy,Careful) pull rod out and measure. Careful if you decide to modify stops. You can get too much roll and throw the geometry off causing the bucket to bind and not roll back. :thumbsup:

Why disconnect the hoses?

Why not just pull the pin and power extend, like he already did?

 

[houser52]

Update-

After taking all the measurements of the dump cylinder while connected and disconnected to the SSQA, it looked like I could gain 1 1/2" of extension if I cut the stops off of the loader's boom.
I only cut off the stop tabs and the reinforcements were left on the boom and SSQA. Those reinforcements now serve as the stops. I ended up gaining 1 1/4" of extension and the cylinders still clear the boom when extended. That extra 1 1/4" of extension left me with 1/4" before the cylinders bottomed out and I now have almost a full dump with the loader raised all the way. It's a lot better than before.

I just cut off those stop tabs on the bottom of the boom.


With those stop tabs gone, now the SSQA stops contact those reinforcements underneath where I cut the tabs off. The cylinders are 1/4" from full extension.

 

[Xfaxman]

Good to know, glad it worked. :thumbsup: