Bosch 11236VS hammer drill intermittent hammer

[halo]

Having problems with the hammer part of this drill. The drill runs perfect but the hammer part has a mind of its own. Everything sounds like its working in hammer mode but no hammer. It worked great when new but when the unit gets hot it usually stops hammering with just the noise of what should be hammer mode. I'll put it down for 30 minutes with a 50-50 chance that it starts hammering again. Sometimes, the unit will hammer through a job, sometimes not. I took the unit apart with the brushes in good condition. The common o ring wear problem from a previous poster was checked and seems to also be in good condition. Not sure what else to look at except gobs of grease all over the internals.... Any help appreciated

Dave

[qdea]

There are two places of possible defects that this condition would be occuring from.
On the xploded view of the tool model, item # 27 which is call the striker,on the striker theres an o-ring if that is worn, secondly you'll need to check item # 830 called the drive end shield which is actually a bearing that might be bad too and could case that condition.

[halo]

How can you tell if the drive end shield is bad? Would hate to just start replacing until I hit the right part. The o ring looks ok from what I can see. Thanks for the info

[qdea]

usally the outer ring separates from the inner bearing body,or balls from the bearing may be missing.