Chainsaw Repair

Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Poulan => Topic started by: The Ripper on January 25, 2014, 07:57:47 am

Title: Crank Seals
Post by: The Ripper on January 25, 2014, 07:57:47 am
Are some engine/ body   parts becoming obsolete for the 3700/3.7 cuz it seems like the C/S's are a no go or is there a cross over seal available?
Title: Re: Crank Seals
Post by: fossil on January 25, 2014, 09:01:47 am
Yep.
For 3400, 3700 & 4000. All the same case and crank.
Any of these the following work great.

National 253747
SKF 6119
SKF 6120 single lip 
Title: Re: Crank Seals
Post by: The Ripper on January 25, 2014, 09:50:18 am
Fossil, A big Thank You on the lip seals #s ;)
Title: Re: Crank Seals
Post by: fossil on January 25, 2014, 04:55:21 pm
You're most welcome. Just a tip on the install,
On the clutch side there is a 90 deg step that the seal must go over and it is very easy to damage the seal going over this step. There are lots of different home made tools but I take a piece of 1/2" copper plumbing pipe and cut one end with a hacksaw and the other with a tubing cutter.
Clean off all burrs and put the saw cut end against the step on the crankshaft and slide the seal over the tube cut end which is curled down. If you don't have a tubing cutter you can sand a chamfer on that end.
The seal can go on the pipe before you place it on the the crank. don't forget to grease the tube.
This will allow the seal to ride right over the step with no damage.
Title: Re: Crank Seals
Post by: fossil on January 25, 2014, 05:10:04 pm
Ripper,

If you want a repair manual for your 3700, PM me your e-mail address and I will send you one.
I don't think I can upload it on the forum as it's 4.7MB
Title: Re: Crank Seals
Post by: 3000 FPS on January 25, 2014, 07:22:11 pm
You're most welcome. Just a tip on the install,
On the clutch side there is a 90 deg step that the seal must go over and it is very easy to damage the seal going over this step. There are lots of different home made tools but I take a piece of 1/2" copper plumbing pipe and cut one end with a hacksaw and the other with a tubing cutter.
Clean off all burrs and put the saw cut end against the step on the crankshaft and slide the seal over the tube cut end which is curled down. If you don't have a tubing cutter you can sand a chamfer on that end.
The seal can go on the pipe before you place it on the the crank. don't forget to grease the tube.
This will allow the seal to ride right over the step with no damage.

One of the other methods that I have used is piece from a aluminum soda can.    Good info there Tim.
Title: Re: Crank Seals
Post by: fossil on January 25, 2014, 08:36:16 pm
Some saw mechanic I am Roger. Changing cases on a Craftman 3.4 today. I spun the clutch off with a small butterfly impact. The result was much like running one with the clutch cover off. Still looking for one of the clutch shoes. At least it's in the basement.  :o
Title: Re: Crank Seals
Post by: 3000 FPS on January 25, 2014, 09:34:41 pm
Some saw mechanic I am Roger. Changing cases on a Craftman 3.4 today. I spun the clutch off with a small butterfly impact. The result was much like running one with the clutch cover off. Still looking for one of the clutch shoes. At least it's in the basement.  :o

Impacts I think are the way to go for that job but you do have to be careful and do not become over zealous.   I usually just do short bursts.
Title: Re: Crank Seals
Post by: Eccentric on January 26, 2014, 03:18:52 am
Yep.  And dial down that butterfly impact.    Start light and turn the power back up only as needed to bust 'er loose.