[tBaker]

Our LB15II-MY recently began leaking like a sieve from below the Y-axis cross slide. The leak was very heavy and had filled up the base of the Y-axis ballscrew housing.

Upon investigation, I found that the top two pistons that control the brakes (?) on the cross slide had sheared from their respective brake nuts. I believe that these pistons are traveling too far as a result and fluid is being pushed around them. Looking at the parts book and not knowing this machine well, this is my best guess. Does that sound reasonable?

I'm expecting the other two pistons to be in similar shape, but they sit directly below the turret. Other than removing the turret, is there a way to access these cross slide brakes?

[OkumaWiz]

Usually the axis brakes are electronic with the exception of the C axis.

I would suspect a way lube or hydraulic leak from the turret clamp to be the the problem.

Best regards,

[rwurm]

I agree with OkumaWiz. The X axis brake should be on the motor. I've never seen a brake setup clamp on the slide ways. The only physical brakes I've seen, like OW said have been on a c axis.

[deadlykitten]

i am not sure, but i think that also W / tailstock has mechanical clamp

[tBaker]

Usually the axis brakes are electronic with the exception of the C axis.

I would suspect a way lube or hydraulic leak from the turret clamp to be the the problem.

Best regards,

Attached are some pictures of what I'm looking at. I've highlighted the parts in question on the manual page. Is this not a brake assembly? The final picture is of the broken piston. Two are accessible above the turret. Two are sitting beneath the turret, and I'm not sure of their status.

Thanks a lot,
Taylor Baker

[underthetire]

Those are slide locks, I remember those on the LB15II only. Someone crashed the $&# on that. Turret has to be lifted off, but if I remember correctly, removing cable clamps gave you enough room to lift up enough and not have to disconnect much. Just brace really well, since you will be working under it. Once you get it back together, you will need to reset zero offset on the axis so it doesn't move when you lock and unlock, otherwise you will end up with diff errors.

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[tBaker]

Thanks for the quick reply. Looking at what's in front of me, it makes sense that the leak could be a result of these pistons overtraveling in their cylinders. Is that a reasonable assumption? They certainly need replaced either way, it seems.

[deadlykitten]

Attached are some pictures of what I'm looking at. I've highlighted the parts in question on the manual page. Is this not a brake assembly?

hy tBaker, i never opened a lathe/turret so far, but i would say that those pistons are not there to break, because there is no comand mechanism attached do them, they just are ... brake can not be passive

The final picture is of the broken piston

what underthetire said seems reasonable ; conection between this broken cilinder and your oil leak, would be if they work sealed, and once it broke, oil leaked out from the turret, so maybe this things are not conected

just replace those, and run the lathe with the turret opened, and inspect 2 find the leak source

Looking at what's in front of me, it makes sense that the leak could be a result of these pistons overtraveling in their cylinders. Is that a reasonable assumption?

i don't know if those cilinders contain oil ... even so, as i see from the images, they are not conected to a hydra system, and cilinders with oil on their own exist, but they require an external force, external mechanical comand mechanism ...

just open the one that broke, and try to figure it out what it does and how it works if they are "oil free", replace them and inspect lathe while runnig

i would strip away an Y turret to give you some help, but i rely on you

[tBaker]

I wanted to update you all so as to help anyone with this issue in the future.

We set an A-frame hoist above the machine and removed the turret. The other two pistons were sheared off as well. I can only imagine a hellacious crash caused this.

This part is actuated through a hydraulic port at the top of the slideway plate. They were, indeed, overtravelling in their cylinders and allowing fluid to pass around their seals.

The pistons were replaced and new seals all around. The turret was put back in the machine and realigned. No more leak.