I have been having trouble with the air and oil knockout cylinders on 2 of my juniors. I have 3 that have never given me a problem and 2 that wont stay running. Even bleeding the hydraulic evry morning doesn't help. When the cylinder doesn't knock the tool out fast enough the tool change arm slips off and all kinds of bad things happen. Unfortunately there is no real way of seeing it coming before it happens. We have bandaided the problem in the past but a failure can cost up to $1000 to repair. I've had the cylinders rebuilt made sure the air pressure is correct. My distributor that supplies service for them is fairly stymied also.Does anyone know the fix or even better is there a retrofit available.

Have you checked the knock dimension? I had this type of problem a few years ago and increased the knock to .030".

RRL

No retrofit I know of. VERY early ones had a check ball in line for the oil. The check ball seat wears out. This type would have an external oil tank. Other issues are bad spindles. If the spindle gets hot it will sweat the tool in over night and give you all sorts of headaches in the morning. Normal tool Knock out is .02-.04.
Newer type has a "Lucifer" valve on the front of the cylinder. Looks like ( and it is) a solenoid on the base of the unclamp cylinder. Those do go bad and leak. This will cause the unclamp pressure to drop, especially in manual tool unclamp.

hi has any one checked draw bar tension if bellville dish spring are dry no grease or broken will cause the release to be slow and stick

nakatome