Stihl Crank Seal installation Questions

[drf255]

I install the seals with 2 stroke oil on them, no sealant. Never a leak (With OEM Seals).

The PTO side lip can make the seal prolapse and lose the spring without the proper tools or using the coke can trick. The fly side keyway notch can cut or damage a tight seal, but I generally put some pressure on the contralateral side so the seal pushes over that area.

The OEM install kits for the seals are invaluable. Worth it IMHO, and multiple models can be worked on with the same tools. It seems that the fly side have 2 depths, with the 1128 series being deeper.

2 questions. Did you install the seals dry? Are the OEM?

I do the Wolfy trick as above. A tiny leak won’t make any difference BTW. We all get OCD about saw sitting for an hour and holding vac, etc... I forget the exact recommendation from Stihl, but it’s less critical than one would expect. Something like pulling 10mm Hg vac and having less than X amount of leak over a minute. Once you actually get a poor runner with a vac leak you’ll understand. Bad runners with enough leak to cause poor running either can’t hold any vacuum, or the needle drops like a lead balloon over a second or two.

 

[Vintage Engine Repairs]

I install the seals with 2 stroke oil on them, no sealant. Never a leak (With OEM Seals).

The PTO side lip can make the seal prolapse and lose the spring without the proper tools or using the coke can trick. The fly side keyway notch can cut or damage a tight seal, but I generally put some pressure on the contralateral side so the seal pushes over that area.

The OEM install kits for the seals are invaluable. Worth it IMHO, and multiple models can be worked on with the same tools. It seems that the fly side have 2 depths, with the 1128 series being deeper.

2 questions. Did you install the seals dry? Are the OEM?

I do the Wolfy trick as above. A tiny leak won’t make any difference BTW. We all get OCD about saw sitting for an hour and holding vac, etc... I forget the exact recommendation from Stihl, but it’s less critical than one would expect. Something like pulling 10mm Hg vac and having less than X amount of leak over a minute. Once you actually get a poor runner with a vac leak you’ll understand. Bad runners with enough leak to cause poor running either can’t hold any vacuum, or the needle drops like a lead balloon over a second or two.

Trust this guy, he’s the 026/260 saw build king.

 

[FernGreen]

I install the seals with 2 stroke oil on them, no sealant. Never a leak (With OEM Seals).

The PTO side lip can make the seal prolapse and lose the spring without the proper tools or using the coke can trick. The fly side keyway notch can cut or damage a tight seal, but I generally put some pressure on the contralateral side so the seal pushes over that area.

The OEM install kits for the seals are invaluable. Worth it IMHO, and multiple models can be worked on with the same tools. It seems that the fly side have 2 depths, with the 1128 series being deeper.

2 questions. Did you install the seals dry? Are the OEM?

I do the Wolfy trick as above. A tiny leak won’t make any difference BTW. We all get OCD about saw sitting for an hour and holding vac, etc... I forget the exact recommendation from Stihl, but it’s less critical than one would expect. Something like pulling 10mm Hg vac and having less than X amount of leak over a minute. Once you actually get a poor runner with a vac leak you’ll understand. Bad runners with enough leak to cause poor running either can’t hold any vacuum, or the needle drops like a lead balloon over a second or two.

I installed the seal with a dab of grease on the lip but not on the backside of the seal. I didn’t put anything on the outer edge of the seal to help It seal to the case. I used an oem seal that came in the oem gasket set.

 

[BuckthornBonnie]

There’s plenty of ways to do it, but some Stihl manuals called for sealant on the OD of the seal. I use Loctite 518, Dirko, or Hondabond depending on the condition of the case. If it’s perfect, 518. If not, one of the other two.

+1 with Doc’s seal leak experience.

Again, most 1125s have enough room to slide the seal over the key area. It should be clean and free of burrs.

OEM seals are the best, but I have installed a ton of AM seals with no failures (yet...)

 

[BuckthornBonnie]

Trust this guy, he’s the 026/260 saw build king.

034 uses those same pesky seals, too.

 

[FernGreen]

I use Loctite 518, Dirko, or Hondabond depending on the condition of the case.

Is hondabond the same thing as yamabond 4? I was gonna pick up some yamabond 4.

 

[BuckthornBonnie]

It’s very similar. I don’t know the chemistry well enough to say it’s the same, though.

It’s a silicone sealant but doesn’t off-gas acetic acid (vinegar) as much as RTV and Dirko. I like it a lot.

 

[Vintage Engine Repairs]

I love a sealer thread. I have gone back and forth between Dirko and Permatex. Dirko is nothing but a glorified RTV. Permatex is more akin to an adhesive.

Dirko isn’t fuel safe, but that doesn’t affect it’s real world function. Permatex *is* “fuel safe” but still, you wipe some fuel on Permatex Motoseal and it will wipe off...

You wouldn’t use it to rebuild carbs or any location is sits in contact with fuel. Ultimately for saws I will be sticking with dirko, it’s just such a good all rounder. Work time is good, easy clean up, seals imperfections.

The thing I have found with Permatex Motoseal is, once it’s tacked up, if you leave it slightly longer and touch it, you’ll take a patch of it clean off exposing metal. I don’t like this considering it requires friction to get oil seals in.

I have heard good things about 1104, but they have replaced it with “1104 NEO“. I recall the replacement no longer contains lead to make it safer, but the newer product isn’t what the old one was?

 

[lone wolf]

Is hondabond the same thing as yamabond 4? I was gonna pick up some yamabond 4.

It will work as intended .