Roto hammer works but leaks oil out the chuck

Most chucks are attached to the drill by an Allen head bolt.
To access the bolt spin chuck open all the way you should be able to see the bolt. Some bolts are a left hand thread so try loosening one way and if that doesn't work try the other direction.
After removing the bolt tap lightly on the chuck to help remove it
A little pentatonic oil is also helpful.
Bob

Look at the drive shaft under the base of the chuck and look for flats on the shaft or a nut. Hold this and use a pair of multi grips on the chuck to unscrew it from the shaft. Or place a bolt in the jaws if they still work and place the bolt in a vice and undo the shaft off the chuck

turn the chuck collar to the hammer Icon

Hello, W/D here.

Open the jaws of the chuck fully. Remove the screw inside. Apply penetrating oil to the inside. Rap the chuck with a plastic hammer, working your way around the chuck, and applying a pulling pressure.
Should come right off.

Best regards, --W/D--

Depends on if it is a keyless chuck or a chuck that needs a key??

the grease is for the chuck as SDS chucks often seize up

It depends on where the leak is. if you email me I can send you an exploded diagram of tis machine. This will give you an idea of how to take it apart.
[email protected]

Where is the oil leaking from. By the chuck, or the selector knob, or is it leaking from where the gear housing meets the motor housing. I could be one of 3 things. There is a seal between the two housings that could be damaged, not likely though. There is an oring on the selector knob that can get worn, and there is a sealed bearing on the spindle that should not let any oil through. There should not be any oil in this tool for lubrication. Grease is used in this tool for lubrication. If you are getting oil or a liquidy type substance coming out it is more than likely the grease has broken down and needs to be replaced.

the oil seal is broken, remove front cover at the chuck end of the drill, and replace the seal,

use 3 in 1 oil, its light and wont hold a lot of dirt or gunk. easy to clean chuck and reapply