Removal of a Stihl flywheel

[SwampDonkey]

Anyone know anything about taking off a flywheel on a Stihl saw? It has woodruff key on the crank shaft, shaped like a half moon and flat. It's a FS550 brush saw, but doubt it can be much different procedure.

Flywheel off Stihl FS550 item #1. The two threaded sections to either side of the centre of the flywheel are worn out. Causes a clankity-clank noise when she spins.




Woodruff Key item #12  That bearing you see is in behind the crankcase. The threaded end of the crankshaft and the key are outside.



Now does the woodruff key keep the flywheel from slipping during rotation on the shaft or from pulling off the shaft? or Both? And if it keeps it from pulling off, what do I use for a tool to depress it some way or some how, to get the flywheel off? It can't be that mysterious. There's nothing to the darn thing. I took the brass nut off already. I notice a slot in the flywheel next to the shaft. I have another diagram of a woodruff key on a gear shaft.

Not a crankshaft in this picture. Item N is the woodruff key. Same set up on the end of the saw crankshaft though.



Any fish?

[chevytaHOE5674]

I have a small puller and use it to put tension on the flywheel. Then I use a small brass hammer to tap on the end of the crankshaft (with the nut installed to protect the threads). The taper of the crank shaft is what keeps the flywheel on the crank, the key is just to keep it from rotating.

[SwampDonkey]

I figured after examining it some more I had to use a puller. My puller I borrowed is too beefy. I'll have to maybe get another one with slimmer jaws. My crankshaft has a hole bored for the tip of the puller centre bolt. I am working in a cramped space because there is a crankcase held together by screws in behind the flywheel and in the way for the most part except maybe at a couple points to get a 2 claw puller into. I've got every other screw out including the muffler, fuel tank and the carburetor. I've gotta do some cleaning on those anyway. I soaked the rust reaper to the shaft for the night.

Thanks.

[tlandrum]

on a stihl saw i use a cut down piece of 1/2 in pipe with a nut welded in it . thread the pipe into flywheel and use nut and bolt to remove

[SwampDonkey]

I see that can be done on my brush saw to, it's threaded inside the flywheel. I can even pick one up already made.

Thanks for the insight.

[Al_Smith]

Most of the Stihl models except the larger  models use a 22 mm by 1.5 thread spacing  internal thread on the flywheel .These can be purchased often on E-bay .In my case being a tight wad I make them from a metric hydraulic fitting . I think on that so far I've shipped out about a dozen and a half .

[Ed]

Al, got a part number & brand on the fitting? I started tearing down my 026 for crank seals tonight.

Ed

[joe_indi]

This has worked for me for the past 15 years, so it should be simple enough for you:
Remove the flywheel nut and spray a bit of WD40 or similar stuff onto the crankshaft/flywheel
Screw the flywheel nut in till its outer surface is level with the crankshaft tip.
Hold the engine by the flywheel.
Tap on the crankshaft tip sharply, once or twice.
That flywheel should come off.
The woodruf key is only for holding the flywheel in the correct position for  proper ignition timing,while the nut is tightened down, so that the flywheel can sit tight on the taper of the crankshaft.
Joe

[SwampDonkey]

I was given that option to Joe. But didn't like the idea of whacking the crank shaft too well. You can't really hang on the the flywheel too well that way, since the crankcase surrounds it and only comes off when the flywheel is removed. Screws in behind the flywheel.

[SwampDonkey]

Al my flywheel is 22 mm as well, end of shaft is 8mm (5/16") diameter.


Got a couple requests in on ebay for shipping cost. By the time I run all over creation to find a hydraulic fitting, I might as well get it off the internet. I learned that a long time ago in this area. No matter what, they won't have what you want.

[Dave Shepard]

The flywheels I've removed I just put a center punch in the end of the crank, then whack it hard with a heavy hammer. Of course, the saw will shoot across the bench, which it has to to work, don't clamp the saw down!

[Al_Smith]

Al, got a part number & brand on the fitting? I started tearing down my 026 for crank seals tonight.

Ed

It's just a "bango " fitting .They come in different tubing sizes with a 22 mm threaded part on the end ,straight threads not tapered pipe threads . I get mine from discards at work out of the scrap tubs .I imagine though for what they cost you'd be about as well off to buy a puller as to buy the fitting  and make your own .

Now I'll tell ya what .I'm going to take a chill pill and give it a shot once again downloading a picture .I have never had any luck so far but if I do I'll post a picture of a homemade puller .Unless some kind viewer of which I've sent them too can help out and load a picture . Too early in the day for chill out medicine,maybe after the sun is over the yard arm .

[Rocky_J]

Al, send me the picture and I'll post it for you. 

[Al_Smith]

I don't think I have your E-mail B .Let me check .

I thought I sent you a puller .If not I will .

[joe_indi]

I was given that option to Joe. But didn't like the idea of whacking the crank shaft too well. You can't really hang on the the flywheel too well that way, since the crankcase surrounds it and only comes off when the flywheel is removed. Screws in behind the flywheel.

You dont want to hang on to the flywheel, fine, just hold a big screw driver between the crankcase and the flywheel and apply pressure onto the flywheel as if you are trying to prise it off with the screw driver, then tap the crankshaft .
With the nut flush with the crankshaft, dont worry, you will not damage the crankshaft.

Well, if you still feel you're not upto that, the only other tool that can do the job is the Stihl flywheel puller # 1110 890 4500.
Is this the image Al?




This is one of the most common of Stihl pullers since it is used on brushcutters like the FS500, 550 or chainsaws such as the 260 , 360,380 and ... yes the 460.
The outer thread goes onto ther thread on the flywheel hub.
Hold the puller in place with a spanner and screw in the inner bolt. Voila!! The flywheel comes off the shaft.
This puller would be in use with every  Stihl servicing dealer.
Joe

[Al_Smith]

 
Well, if you still feel you're not upto that, the only other tool that can do the job is the Stihl flywheel puller # 1110 890 4500.
Is this the image Al?

(Image hidden from quote, click to view.)


 

That's pretty much it Joe .I've made several different ones using various sized bolts depending on the size of the internal openings .Some with 1/2" 20 thread ,m11 -1.5 ,1/2"- 13 TPI .Just depends on what I have around at the time I'm making them .

Rocky should  have a pic on here shortly .

[SwampDonkey]

AL and Joe, how do ya like my flywheel puller? I had to make it a little different as they didn't have that type fitting with 22 mm x 1.5mm thread. Accept they did have one with the proper thread on one end for the flywheel and then another screwed on (silver) to the back. I drilled a hole a 5/16" hole in the silver fitting, threaded with a 3/8" tap. Ground down a nut a little thinner and tapered a bit, because of space inside the silver fitting. Took 3/8" threaded rod and cut a 3" piece off. Screwed the thin nut onto it so it came up flush to the brass color fitting, turned on the back fitting until it came flush to the nut inside and the whole assembly hit flush onto the end of the crankshaft. Put on a lock water and nut on the outside of the threaded rod until flush to the back of the silver fitting. These are 1" fittings, means it takes 1" wrenches. I have the pulley assembly off the back so I put a ratchet onto the crankshaft nut back there. Turned the home made flywheel puller onto the flywheel threads and pop goes the weasel.

Thanks for the tip Al. Here are some pictures to study.







Less than $10 bucks and eBay wants anything from $8.50 to $35 plus shipping. 

I tell ya right now that no screw driver and taps would'a took that off, at least not on my flywheel.

[Rocky_J]

Looks like I'm late to the party, but here's Al's picture. 

[Al_Smith]

Thanks for posting that .I might add that the center of the bolt was turned to a  point to engage with the centering hole of the crankshaft .Kind of similar to the factory made puller . It was  little tough to do on a grade 8 bolt through,hard like a rock .

I'm not one who likes to beat on the end of a crankshaft to get the wheel off .Fact is for every make of chainsaw or engine I have and need to pull the flywheel I fabricate something that will work .Whatever ,however anyone else does with their own saws is none of my business and I'll leave it at that .

[Al_Smith]

After thought .There is a puller that I thnk was designed for Mopeds that is reversable .It has a M22 on one side and M26 on the other .M 26 is used for larger Stihls but I've never personally had the occasion to need that size as yet .If I can find a fitting some place though I'll make one or have one of my toolmaker buddies turn me one .My lathe will not cut metric threads .

It's a good old Monarch 10" EE ,one of the best but it has a few years on it .Back when noone ever thought that the USA would ever be metric . The change gears for that thing to cut metric would cost a bloody fortune if I could even find them .