Sachs Dolmar 153 clutch issues

[Sapo_feo]

Is there a secret to keeping the clutch on a 153? I had a new clutch put on and it will not stay on. The original sprocket was incorrect for the saw, so I got a new bushing, new bearing, and new sprocket and new clutch spider. Still no luck keeping it on. Not sure about the first try, but the second install with the new spider was done after the taper was cleaned with xylol. The taper doesn't appear to be damaged and is uniform. Any suggestions would be appreciated.

 

[Four Paws]

Did you stop the piston and torque the nut properly? Assuming you did, next question would be, is the clutch you have indeed a 153 clutch?

 

[Sapo_feo]

The nut was torqued to 19ftlbs. It has the proper shoes, as far as if it is the proper spider, I don't know. It measured out the same as the old one, but nothing on the saw was to spec when I got it.
If there isn't a specific technique to installing the clutch I can put the new shoes and spring on the old spider and see what happens.

 

[Four Paws]

19 ft-lbs sounds light...but you definitely don't want to twist the end off the crank.

I would torque it to a higher value, or just torque by feel, stopping just before breaking stuff!

If that doesn't work, I would swap parts onto your old spider if it isn't worn.

 

[Jacob J.]

Do you have the correct washers installed? The new clutch spider is a good fit on the crank?

 

[Sapo_feo]

I have no idea if the washers are correct. There are no part numbers on anything, and you can't trust the bay. I have several sprockets that were sold with the correct part number listed, but were 19mm when they arrived. Here are some pics of what I have going on. Sorry about the focus, the old camera didn't want to cooperate. And you'll probably notice the sprocket is marked .404, but it's 3/8. Another surprise from the bay.

 

[Modifiedmark]

It appears you have the correct race and bearing so that shouldn't be it. When you say it won't stay on, do you mean it won't stay tight and is spinning on the crank?

The clutch to stay tight is dependent on the flywheel taper being exacting to the clutch spider. I would try this with the new spider, get some valve lapping compound put it on the taper of the crank, put the spider on and spin it by hand to lap the 2 tapers together, inspecting it once in a while to see if there lapping together evenly. If the lapping looks good, clean it all off good then tighten the piss out of it when you put it back together. I suggest a 3/8's impact to set it, then tighten it by hand tight as you dare.

It also sounds like you have been a victim of the common practice of listing sprockets to fit both the 152, 153 and 166.
As you found out the 144/152 sprocket won't fit a 153.

If you really want a .404 sprocket for it, let me know I think I have one for a 153 that I will not ever be using. I have 2 of these saws in Poulan colors and try as I might I can't bring myself to love these saws.

 

[Modifiedmark]

While I'm at it let me also caution you when using pullers on either end of that crankshaft. Look how deep the center hole is drilled, makes it very weak. At least make sure the nut is on the end of the crank when using a puller on it.

The Flywheel side is even worse and weaker. I didn't realize it and broke the threaded end of the crank off trying to pull the flywheel. Seems Dolmar made a special puller for these saws and part of it fit into that hole in the crank. Lee H told me this and to not feel bad that he had done the same thing.

 

[Sapo_feo]

Thanks for the reply's. I am not a fan of this saw and hope I never have to pull the flywheel. I got it because it was the only 6 cube with an aux oiler I haven't tried. My 2100 is getting tired, and I truly dislike the 655 BP, I have some long bars from an 084 I used to have so I thought I'd give it a shot. I should have bought a used 3120, I would have saved some money. And parts are still being made. But I made my choice and it will run even if I have to weld the clutch on. I'm not going to do that, but it's tempting. I like MM's idea of lapping the tapers, would I be better off using the old spider which may already be fitted to the shaft or starting fresh with the new spider? As far as the 404 sprocket, I could use one since all my long bars are 404, but I have a tiny 28" 3/8 that will do fine until I get the clutch to stay on. To answer the question of what is happening with the clutch; It will stay tight until I hit wood. 20 seconds into a cut and it slips. It will stay tight at high idle and rev as long as you want, but first contact is the last. Tomorrow I'll try lapping and let you know how it works out. Thanks again.

 

[Sapo_feo]

It took a while to find some lapping compound. The only stuff I could get is water based. I've never used it before, only grease based. It will be this weekend before I will get around to testing it.

One further question: Has anyone used Loctite 680 on a saw clutch? Good experiment or bad idea?

 

[burnses]

I had a sachs 152 that I saved from the dumpster fixed it up and wished I still had it in a way but I was beginning to show the early signs of "boschitis" but I managed to cure it before I sold it...as the the clutch taper....I looked at that and said "no way buddy" but I also know tapers that fit really work...I cant remember if I lapped it or not but I did ck the fit with a little white grease on the crank and fit the spyder and checked that the grease was evenly transferred to the female taper...then I cleaned it with lacure thinner and I seem to remember putting the saw in the barn freezer to get the crank cold and warmed up the spyder with a heat gun or blow torch fit it on and used a spacer and the nut to push it o tight as it all came up to temp...tapers are all about that slight interference fit..ran a few tanks through it never had any problems...loved the was that saw sounded....good luck oh and I almost ruined the crank taking the flywheel off but realized what I was doing before I totally mushroomed the threads....rugged saw though

the can

 

[burnses]

sounds like just the nut is coming off...loc tight primer followed by red loc tight and let it set up over night and you will have to heat it to take the nut off....also if you have the correct bearing inner race or spacer the outer washer under the nut will tighten on the washer which in turn through the spacer or inner race registers/bottoms on the shoulder of the crank not on the bearing and crushing it...that's how the clutch can disengage at idle....

 

[Sapo_feo]

From burnses description I may have the wrong guide disk. Is the sprocket bearing bushing supposed to fit through the guide disk hole and contact the clutch? If it is that means I have a 152 guide disk, because the hole is not large enough for the bushing to go through. If the bushing does need to fit through is there any harm in just drilling the hole out or do I need to find a real 153 guide disk?

 

[burnses]

I think I may have complicated the issue....if you tighten the nut and the clutch drum can freewheel the I think the spacer bearing ect. is ok then just Loctite the nut and give it a try if in fact the spyder is staying on the taper.....

 

[nstueve]

While I'm at it let me also caution you when using pullers on either end of that crankshaft. Look how deep the center hole is drilled, makes it very weak. At least make sure the nut is on the end of the crank when using a puller on it.

The Flywheel side is even worse and weaker. I didn't realize it and broke the threaded end of the crank off trying to pull the flywheel. Seems Dolmar made a special puller for these saws and part of it fit into that hole in the crank. Lee H told me this and to not feel bad that he had done the same thing. View attachment 471591

I'm glad i read your earlier posts on this as the 123-143 series seem to be the same. Mike made me a stainless puller for these that works fan-freaking-tastic!

 

[nstueve]

From burnses description I may have the wrong guide disk. Is the sprocket bearing bushing supposed to fit through the guide disk hole and contact the clutch? If it is that means I have a 152 guide disk, because the hole is not large enough for the bushing to go through. If the bushing does need to fit through is there any harm in just drilling the hole out or do I need to find a real 153 guide disk?

I would just reuse the original inner spider that was known to mate with the crank and stay put. Seems like the easiest option... Or am I missing something?

 

[Modifiedmark]

I think I may have complicated the issue.....

You think?

I already stated it appeared he had the correct parts.

The nut is not the issue, it is used for tightening things up in the beginning and to hold the sprocket on afterword's.

 

[Modifiedmark]

From burnses description I may have the wrong guide disk. Is the sprocket bearing bushing supposed to fit through the guide disk hole and contact the clutch? If it is that means I have a 152 guide disk, because the hole is not large enough for the bushing to go through. If the bushing does need to fit through is there any harm in just drilling the hole out or do I need to find a real 153 guide disk?

The inner race tightens up against that washer.

At this point not being there I have to wonder if the taper on the crank might be a bit galled from the clutch spinning on it? If so it maybe hard to get a clutch to fit on it properly again.

But again, I aint there to see it.

 

[Modifiedmark]

I'm glad i read your earlier posts on this as the 123-143 series seem to be the same. Mike made me a stainless puller for these that works fan-freaking-tastic!

And that is another reason I no longer own the 133 that I had. No reason for the Germans to over engineer something as simple as mounting a clutch or needing special tools every time you turn around.

 

[leeha]

I have never had any problems with clutches on Sachs Dolmar saws. The heat method
i like and use it on Mac's as well. Only issue i have had is like Mark did with the crank end
but my issue was on the flywheel side. Must use a cap on the end of crank so as not to
damage the crank like in Marks photo. If your not keeping the clutch tight on the taper
then your tapers are not correct. Really difficult to give you all the help you need without
seeing the saw in person. If the clutch spun on the crank then more than likely the two
parts have some sort of damage.


Lee