Jonsered 670 chain brake slipping

[Chris J.]

The chain brake on the Jred 670 is built into the clutch/bar cover (which may partially explain why finding a replacement cover is sometimes difficult). On my West Coast model the chain brake slips into the on position when it's in the cut. It no longer has enough tension to hold the brake arm in the Off position, & I don't see a way to adjust the brake.

A solution that comes to mind is to add something to the portion of the brake that is attached to the cover, to make it more difficult for the brake arm to slide over into the On position. Of course it would be best if the chain brake still popped into the On position like it was designed to do.

My digital camera is taking foggy pictures, but page 7 of the manual (link) shows the indention & notch that are supposed to hold the brake arm in place.

Your comments & thoughts would be appreciated.

http://www.jonsered.ws/670625.pdf

 

[taplinhill]

Sounds like the knee-joint is worn. That part alone is probably $30-$40 (not sure) if you can find it. An aftermarket cover/brake/handle is available for $40-$50. It is made for the Husqvarna saws in the family but should fit. I can check tonight if you want to know.

 

[Chris J.]

Taplinhill, that information would certainly be appreciated, & thanks for providing the proper name for the part. I had read or heard knee-joint somewhere, but couldn't remember it.

The "if you can find it" is the hard part; I've scored a few 670 parts from George Blake/Motorsag. I've also snagged a couple of 670 parts saws, but the clutch/chain cover is usually missing, or the chain brake is shot.

 

[SawTroll]

One option is to remove the chain brake altogether - but don't tell anyone that I said so........

 

[scotclayshooter]

One option is to remove the chain brake altogether - but don't tell anyone that I said so........

SAWTROLL!!!! lol :jawdrop:
Sort of like if we took the airbag out of the steering wheel of the car and replaced it with a big sharp spike! we would all be more careful drivers!

 

[Chris J.]

Sawtroll, I've seen more than a few 630s & 670s listed where the sprocket cover is on the saw, but the chain brake arm is missing.

 

[Oldsawnut]

I know I remove all mine... I have had a couple slip on when I am hard in the cut before and you about s@#$%@#$t your pants. Its weird because 2 separate saws did it on a regular basis and nothing would even touch the flag. That's when I started taking them off. Not to mention its darn hard on the saws. The 61-272 husky is the counterpart but the covers don't really match up well. IMO the newer style husky jred brakes are muuuuch better.

 

[SawTroll]

Sawtroll, I've seen more than a few 630s & 670s listed where the sprocket cover is on the saw, but the chain brake arm is missing.

Yes, looks like it is pretty common on those saws, as well as the Husky counterparts.....

Some of the Huskys are still made (in Brazil), so new parts should be availiable.

 

[taplinhill]

Well I got around to checking it out. This is an aftermarket Husqvarna 61/268/272 assembly on one of my 670's.



.

 

[Chris J.]

taplinhill, if you don't mind telling, where did you get the aftermarket cover/brake? Would Bailey's or Simonian's stock it, or be able to order it?

I'm still considering tinkering with the knee-joint, but knowing my mech/tech skills , the chances are good that a new one will be needed. Also I have enough 670 parts saws/parts to assemble a second running 670.

TIA!
Chris J., cityfied certified

 

[taplinhill]

taplinhill, if you don't mind telling, where did you get the aftermarket cover/brake? Would Bailey's or Simonian's stock it, or be able to order it?

I'm still considering tinkering with the knee-joint, but knowing my mech/tech skills , the chances are good that a new one will be needed. Also I have enough 670 parts saws/parts to assemble a second running 670.

TIA!
Chris J., cityfied certified

I have seen them in their catalog, but not on the website. They are also available from several sellers on ebay.

 

[Chris J.]

I decided to tear down the chain brake to see if I could bend the one of the pieces out so that the brake wouldn't slip into the on position. All went pretty well, if you don't count almost losing the large pin. I bent the piece, then reassembled everything with an extra washer added. I was fighting with the spring when I decided to stop there, & get the chicken in the oven to roast.

Take a wild guess what I spotted when I was straightening up my work area.

 

[bama]

I decided to tear down the chain brake to see if I could bend the one of the pieces out so that the brake wouldn't slip into the on position. All went pretty well, if you don't count almost losing the large pin. I bent the piece, then reassembled everything with an extra washer added. I was fighting with the spring when I decided to stop there, & get the chicken in the oven to roast.

Take a wild guess what I spotted when I was straightening up my work area.

I'll bite.....You noticed a piece that should have been included in re-assembly?

or

You found out where you had laid those gizzards as you were preparing the chicken and fixing the saw at the same time.

 

[bama]

taplinhill, if you don't mind telling, where did you get the aftermarket cover/brake? Would Bailey's or Simonian's stock it, or be able to order it?

I'm still considering tinkering with the knee-joint, but knowing my mech/tech skills , the chances are good that a new one will be needed. Also I have enough 670 parts saws/parts to assemble a second running 670.

TIA!
Chris J., cityfied certified

Bailey's has them. Page 27 of the new catalog. $49.95 complete with the guts. part number QH 503 73 66 01

 

[Chris J.]

I left off the arm that has the paddle on it . Maybe subconsciously I was taking SawTroll's advice? Oh well, at least I didn't do a complete rebuild and then find both the old & new gaskets on the work bench.