Barneys mate

Struggled with welding gloves: berberis spikes and blackthorn would get through them too easily.

Ended up with Ripeur 2 gloves and a pair of Bradleys leather arm protectors underneath:

https://www.bradleysthetannery.co.uk/collections/gloves/products/heritage-leather-arm-protectors

It was an expensive set up but its been worth it!

Saw was used all day yesterday dismantling small - medium acer, birch and ash trees.

Brake used frequently (and made sure to kill saw sooner, thanks Sawchip).  Band stayed on the drum and didn't jump into the chain once.  As long as the washer lasts, hopefully problem solved.

Will let you know if it returns.

On 28/09/2019 at 20:39, spudulike said:

The clutch drum will always have a fair bit of float on it, you have to hold it against the clutch and move the whole assembly in and out showing if you have loose engine mounts. Other than this, check the mounting bolts themselves.

Have you checked them yet?

Yes, checked as per your earlier post and all tight.

On 28/09/2019 at 18:51, Sawchip said:

That MS-150 of yours spend a bit if time idling with the brake on ? 

Probably guilty as charged! Need a re think on working practice....

Having put it together, the clutch drum still spins freely on the crank  and most importantly the bad brake stays in place when applied but with the chain running and stationary.  A longer term solution would be a new clutch carrier without the groove!  Hope this is of some interest.

To try and reduce this without pinching the drum against the clutch, I fashioned a "washer" out of a bit of 0.5mm steel sheet to sit between the clutch drum and the clutch assembly but over the crank shaft.  This would reduce the 0.75mm difference to 0.25mm and eliminate the grove.

I also measured the distance between the shoulder of the crank against which the clutch butted when tight and the inside of the clutch drum:  it turned out that there was a 0.75mm gap.

This, combined with the depth of groove, resulted in about 1.25mm of end float.

Thanks bmp01 and I was thinking along the same lines having checked that the mounting bolts were tight (should have mentioned earlier but all parts used are genuine Stihl).  While checking the end float of the crank as per Spuds suggestion (crank all tight) I noticed what seemed a lot of end float on the clutch drum itself.  After taking off the clutch assembly I noticed circular grove about 0.5mm deep on the inside face:

Thanks for that guys.  When my saw was run with my mate's clutch/brake cover, the brake band still slipped off (on my saw) but my cover (and brake band) worked fine on his saw.  Will check out the engine mount bolts, thanks Spud.

Having hassle with the band brake coming off the clutch drum and fouling on one side off the chain (see pic.) when the brake it applied, both with engine running and stopped.

I've changed to clutch/brake cover housing as a complete assembly (you can still see the parts sticker in the photo), spur sprocket and needle roller bearing but the problem is still there.

Swapped a clutch/brake cover housing from a colleague's MS150 and the same thing happens on my saw.

Checked for play in the crank shaft but all tight.

Any suggestions/ideas gratefully received....