My chainsaw pull cord wouldn't pull. Acted like the saw was seized. I took off the the pull cord and it worked fine. Pulled the spark plug and still couldn't move the flywheel. Put a ratchet on the flywheel and rocked it back and forth and freed it up. Piston moved ok but sounded like something was broken. Pulled the bar and chain cover. Found a broken part on I think the clutch. I looked at a parts diagram but it doesn't show the part. There are two steel U shaped bands that sit in openings on the outer edge of the clutch. One is broken and was stopping the clutch from moving. I removed it and the saws pull cord works fine. Does anybody know what that broken piece is called and what is it for. I was thinking it's for the chain brake maybe?

Sounds like it to me. Move the hand guard while watching the part you described as being broken. You should be able to see the connection and how it works. On most saws the handguard in front of the top handgrip is what activates the chain brake.

Maybe try looking up clutch assembly. All the chain brake is, is a band that goes around the outside of the clutch and tightens to it when engaged.

I looked up the clutch diagram and they are not shown on the diagram. I just found them youtube they are called clutch springs. Now I will see if I can get a replacement. Thanks for the help.

If its on the outer part of the clutch bell, its the chain brake. If on the inside its the clutch assembly. Put it back together with bar and chain. Flip the chain brake plate forward then pull on the top of the chain. If you can move it, its a dead chain brake for sure. Or put a picture on here.

Try part number 537 04 30 - 01 it has the 2 U shaped ends you mention on it

consider asking on the Jonsered forum... http://opeforum.com/
and the jonsered guide here http://www.jonseredchainsawguide.com/