Dolmar/Makita 6400-7910 crank seal installation

[Hurst89]

I finally got everything together to start rebuilding my 6401 Makita (Thank you for everyone on here for the help and offers with the cylinder/piston sets!) and was starting with the crank seals last night. I used a small punch and two small screws to pull the old seals, pretty straight forward like normal. I got the flywheel side seal installed just fine (soaked it in 2 cycle oil and coated the crank in oil as well, slid right on). I went to work on the sprocket side and everything was going smooth and I was tapping the seal in with a deepwell socket when I noticed the lip had gotten caught and cut up on the step in the crank where the seal rides. The step-up in diameter is done with very little chamfer, and to make things worst, the seal doesn't start to go up on this part until it is being pressed in, so I cannot move the seal around to work it over the edge. I was wondering before I get another seal and mess it up, does anyone have any tips? I was thinking about wrapping the crank up in Teflon tape to build up the diameter more gradually so the lip won't catch when it hits that part of the crank? I hope I'm not the first one to encounter this problem

Thanks!

Hurst

 

[tickhound93]

Electrical tape wrapped tight is what I use on 1123 series stihls. Same kind of deal

 

[Hurst89]

Yeah, something to get the lip up and over that hump. I'm surprised they didn't add a little chamfer to it, but I guess that would have been one more machining process on every crank. Now to find a seal without paying more than the seal costs in shipping... It's a 17x28x5/4 seal, so hopefully I can find one at the local bearing/seal supplier if none of the dealers carry them in stock. The thing could probably go in a standard 49 cent envelope and make it alright lol!

Hurst

 

[fordf150]

Yeah, something to get the lip up and over that hump. I'm surprised they didn't add a little chamfer to it, but I guess that would have been one more machining process on every crank. Now to find a seal without paying more than the seal costs in shipping... It's a 17x28x5/4 seal, so hopefully I can find one at the local bearing/seal supplier if none of the dealers carry them in stock. The thing could probably go in a standard 49 cent envelope and make it alright lol!

Hurst

shoot me an email on the seal.

as far as installing it, yes they are a pain because of that lip jsut as the seal starts entering the case. If its a one time deal building one of these saws you can use film negative or something similar wrapped around the crank to let the seal slide over the lip. If your going to build more than one, buy the installation tool.

http://performanceoutdoorequipment.com/products/dolmar-944603410 here is what the tool looks like and what your trying to duplicate with the film negative

 

[backhoelover]

micro fish from old pics easier then tape

 

[backhoelover]

beat me to it