Stihl 026 - Change Non-Leaking Crank Seals Anyway?

[a. palmer jr.]

I doubt if you can get much sealant between the seal and the case but you could go around it with motoseal, it's a bit thinner than dirko but doubt if anything would stay on when you push the seal into the case. That idea would work okay on an 025 though but I don't do it and I've never had a leak on a new rebuild. I do recommend lubing the rubber part of the seal though..

 

[a. palmer jr.]

More likely is buggering up the case. Be sure to use sealant between the seal and case and to lube the rubber lips of the seal. Vac test after assembly.

My puller fits between the crank and the seal, not supposed to even touch the case unless you're really careless with it.

 

[bmwpowere36m3]

Depending on the perimeter of the seal, rubber or metal, would dictate the sealant I'd use. You want something fairly "thin" and applied sparingly. Anywhere from an anaerobic like 515/518, hylomar, curil, or ultra black. I'd avoid the anaerobics if the seal is rubber covered.

 

[bmwpowere36m3]

I've used nail polish, after the fact, on seals with metal shells.

 

[HarleyT]

So we are not talking about an 026 anymore?

 

[SteveSr]

So we are not talking about an 026 anymore?

Oops! Sorry, wrong thread! Please disregard. I guess I better go post this where it belongs.

 

[Mad Professor]

My stihl dealer will install seals for $15 if you bring him a clean saw with the clutch and flywheel off.

 

[7sleeper]

I would replace all "rubber" parts(seals, hoses, carb membrane, antivib, etc.), if you intend to keep and use the saw for the next decade. I find that quite "cheep" insurance and would not jump on the line "old" rubber is better than "new" rubber as long as you stay with original Stihl products.
What I would definately NOT do is go aftermarket on the "rubber" parts.

7

 

[blsnelling]

Stihl manuals instruct to use sealant on pressed in seals. I have seen them leak if this is not done. Of course, most of it is pushed out. That's to be expected.

 

[SteveSr]

My stihl dealer will install seals for $15 if you bring him a clean saw with the clutch and flywheel off.

Wish I had a local dealer that would do this for this price! It would make the decision much easier. I know one dealer who I would try but they are in the next town 30 miles away.

 

[SteveSr]

Stihl manuals instruct to use sealant on pressed in seals. I have seen them leak if this is not done. Of course, most of it is pushed out. That's to be expected.

Are the new seals a straight metal shell or are they rubber coated like the ones that I just installed in an 025 clamshell? I could see using sealant with a metal shell but not with a rubberized shell.

I just checked my 026 repair manual which doesn't say to use sealant, however, the 2008 MS260 repair manual does say to use sealant. I guess Stihl found the same thing that you did and changed the procedure to use sealant.

 

[blsnelling]

They are metal.

 

[SteveSr]

They are metal.

Thanks for the confirmation. Where is the best place to put the sealant... In the crankcase bore or on the seal?

 

[blsnelling]

I put it on the seal so as to not push sealant into the bearing.

 

[HarleyT]

 

[SteveSr]

Thanks for everyone's input. I think I will defer judgement until I can fully disassemble the saws and determine the condition of the rest of the rubber and the amount of hours on the saws.

I have seen 15-25 year old 026's with good seals and a 10 year old MS-260 with a big flywheel side crankshaft leak. Go figure! The 260 was well worn and the compression was down a bit. Don't know if it was high hours on the saw or running lean from the leak that caused the wear on this engine. One thing that I have yet to see is an intake boot on this series of saws that was hardened or showed signs of pending failure regardless of age. The intake boots must be good rubber!