Leaking seals?

[SpikeDmax]

I'm rebuilding an old 028WB, after complete dis-assembly (split the case) and cleaned everything, I'm finally putting it back together. I got the case halves together tonight and installed the crank oil seals and then put the jug on and tested for pressure and all looked well, no bubbles in the soapy water. Then I tested vacuum and it wouldn't hold. I then put down a bead of Permatex hylomar ( http://www.permatex.com/products/Au...ng_Formula_Gasket_Dressing_Flange_Sealant.htm) gasket sealant around the seal and it held 10 psi of vacuum.

My question is did I use the right sealant and will it last? It's a sealant that doesn't get hard and stays sticky, my concern is down the road it's going to be covered in wood chips and dust and make a mess. Any suggestions or just run it the way it is? It's holding vacuum but I'm a little pissed at the having to use sealant but oh well, was hoping for a cleaner job.

 

[redunshee]

I'm rebuilding an old 028WB, after complete dis-assembly (split the case) and cleaned everything, I'm finally putting it back together. I got the case halves together tonight and installed the crank oil seals and then put the jug on and tested for pressure and all looked well, no bubbles in the soapy water. Then I tested vacuum and it wouldn't hold. I then put down a bead of Permatex hylomar ( http://www.permatex.com/products/Au...ng_Formula_Gasket_Dressing_Flange_Sealant.htm) gasket sealant around the seal and it held 10 psi of vacuum.

My question is did I use the right sealant and will it last? It's a sealant that doesn't get hard and stays sticky, my concern is down the road it's going to be covered in wood chips and dust and make a mess. Any suggestions or just run it the way it is? It's holding vacuum but I'm a little pissed at the having to use sealant but oh well, was hoping for a cleaner job.

Had a similar issue with my old POulan 3400. Installed seal with sealant and it leaked . Was told to run it a bit and it may seal itself. Sure enough it did. Is fine now. Maybe yours will do the same. I'd give it a try.
Bob

 

[SpikeDmax]

Thanks, Bob.

Any other comments/thoughts out there?

 

[blsnelling]

OEM seals? Where did you put the sealant? Seal to case, or seal to crankshaft?

 

[SpikeDmax]

Yes OEM seals, gold plated by Stihl. Put the sealant between case and seal...not crank and seal.

Maybe as suggested with use and heat/cool down cycle it will seal???

 

[blsnelling]

Heat cycling isn't going to affect the metal-to-metal seal of the seal against the case. What you've done might hold, but it would be best to install it with sealant on that surface if it's leaking. You might try the green wicking Loctite.

 

[SpikeDmax]

Thanks, I have some green loctite and will try it. Will wipe off what I can of the Permatex whats' down in the 'cracks' will help seal and then put down a bead of green loctite. I don't like the 'cleanliness' of the job with sealant showing but looks like I'm stuck.

 

[Chris Crouse]

Hylomar is far and away the best silicone type product around. If any sealer will work there, Hylomar will.

 

[blsnelling]

Hylomar is far and away the best silicone type product around. If any sealer will work there, Hylomar will.

If you choose not to pull and replace, which I understand, I like the idea of Loctite weeping in the crack, and then coating with Hylomar as you have now.

 

[RobertN]

I'm new to this, so I want to see how this turns out. I am tearing apart an 024 basket case right now. Reading everything I can here about it. Also got a PDF version of the service manual. Got it from a Stihl shop; they said it needed bearings. So it will get bearing and seals...

They say:
-Lubricate sealing lips of oil seal with grease
-Thinly coat the outside diameter of the oil seal with sealant
-Install the seals
-After about one minute, turn the crankshaft several times

The grease they refer to is noted in the back of the manual:
-Lubricating grease P/N 0781 120 1111

 

[sugarbush]

I'm new to this, so I want to see how this turns out. I am tearing apart an 024 basket case right now. Reading everything I can here about it. Also got a PDF version of the service manual. Got it from a Stihl shop; they said it needed bearings. So it will get bearing and seals...

They say:
-Lubricate sealing lips of oil seal with grease
-Thinly coat the outside diameter of the oil seal with sealant
-Install the seals
-After about one minute, turn the crankshaft several times

The grease they refer to is noted in the back of the manual:
-Lubricating grease P/N 0781 120 1111

Good advise, but degrease hub and seal then put sealant on hub not seal, easier to handle seal.

 

[blsnelling]

Good advise, but degrease hub and seal then put sealant on hub not seal, easier to handle seal.

But that will cause the excess sealant to be pushed into the case, instead of pushing it off the seal to the outside.

 

[sugarbush]

But that will cause the excess sealant to be pushed into the case, instead of pushing it off the seal to the outside.

it sure will if you put it on heavy enough. a light film is all thats necessary.

 

[blsnelling]

This is the 2nd time recently that I've seen new seals leak on a saw. The other was on a 371 I just worked on. I received the saw as already rebuilt and found it to have a vacuum leak. I replaced the seal and coated it with sealant. Problem solved. I suppose there's a lesson to be learned here.

 

[SpikeDmax]

What do you guys think of this for finding the leak? Pressure testing the case under water? Figured I'd hook up the compressor hose to the impulse line and pump in 3-5 lbs and dunk it in a 5 gallon bucket of water and see where the bubbles come from.

 

[blsnelling]

Just spray the suspect areas with Windex. I'd much rather do that than dunk the entire saw. Others have done it though.

 

[lone wolf]

like brad said windex first i dunk mine when they are absolutely driving me nuts .now if it fails vacum test put some grease on the crank seals to see where it leaking.dont dunk it and do a vacum test it will suck water and rust crank bearings.

 

[blsnelling]

Windex makes nice bubbles. Errr...I guess they're not so nice, lol.

 

[SpikeDmax]

I'm at the being driven crazy part now! Ugh! I wouldn't vac check in the water....don't want to rebuild her again. I would pressure check in the water mostly to see if my case is leaking or blocked off exhaust or cylinder gasket is leaking, basically to rule out anything else but the crank seals.

 

[lone wolf]

seal the base gasket with your special sealer then do a vacum test if it fails put grease on crank bearings one at a time if vac holds seal is bad.