Bosch CMS brake not working 100%

[John TenEyck]

My Bosch 12" DCMS has been flawless since I bought it 8 or 9 years ago, though it hasn't seen heavy use. But yesterday the brake started malfunctioning, either not engaging immediately after I released the trigger, and a couple of times it didn't engage at all, the blade just slowly spun down. Anyone know what the likely source(s) of the problem is(are)? Thanks.

John

[Ken Fitzgerald]

Sawdust in the switch?

[Tom M King]

Try blowing the dust out, but not directed at bearings, and hold the trigger for about 30 seconds, or so.

edited to add: I don't know about that saw, but I have a 447 circular saw with brake, specifically for cutting rafter tails, and that has gotten the brake operating again so far.

[Chris Parks]

My Bosch Glide saw does that when I release the switch slowly, I haven't got s clue why and never looked as I know releasing the switch fast makes the problem go away.

[Jim Becker]

My Delta CMS starts to exhibit that behavior when things get dusty and/or the brushes start to get worn.

[John TenEyck]

Thanks for the input. I blew out the on/off switch (not much came out, but I didn't disassemble it) and the motor after removing the brushes (quite a bit came out) and now it seems to run fine again, whether I release the trigger quickly or slowly. We'll see how long it lasts. FWIW, the brushes themselves looked great.

John

[Richard Wolf]

The brushes may look great but how much shorter are they then when they were new. As they wear the spring doesn't hold them as well. Short brushes are a cause of brake failure.