Stihl 660 Brake too sensitive

[NPKenny]

I am looking for the fix for a Stihl MS660 brake that engages too easily. The basic symptom is that it will occasionally engage during normal cutting. The brake handle has excessive play as well.

Short of replacing the entire assembly, which components are the normal failure points?

Thank you!

 

[HarleyT]

Look for gunk between the brake band and drum, and take off the cover and snap a pic, you will probably see it right off.

 

[Stihldoc]

Gunk is definately a prime cause of this complaint. The flat S-shaped spring in the brake can also cause this issue. clean it all up, take out the flat spring to check it- if its broken it'll be obvious. I see this complaint often in the 020T and MS200 1129 series saws, but all the Stihl brakes are essentially the same.

 

[Adirondackstihl]

Replace the spring.
They can get weak over time and cause this.
PN 1122 160 5500
MSRP $6.99

 

[NPKenny]

Thank you for the responses.

I cleaned the entire assembly and the problem still persists. The break is more defined and crisp, but the brake still engages on throttle. Looks like I will need to replace the spring as indicated.

It may be a few days, but I will report back with results.