Re: 1970 Merc 800 lower crankshaft bearing removal
The bearing is pressed onto the crankshaft. You'll need a bearing separator/puller to remove the bearing, something similar to this:
http://toolsandmore.us/index.asp?PageAction=VIEWPROD&ProdID=328
With this first tool, the face is tapped for bolt holes. Instead of having to buy a fancy puller to go with the separator tool, you could drill a couple of holes in some stout flat bar to match the hole spacing on the tool. Use the flat bar across the end of the crankshaft, with appropriate-length bolts to pull the bearing off.
Here's a couple places with the complete puller/separator kit for just a "bit" more:
http://www.wttool.com/product-exec/product_id/4766?utm_medium=cpc&utm_source=froog
http://www.jcwhitney.com/webapp/wcs..._ID:2007841&productId=2007841&catalogId=10101
A big-honkin' bearing separator which is probably better-suited for our crank bearing than that first one:
http://toolsandmore.us/index.asp?PageAction=VIEWPROD&ProdID=329
Of course all these will vary in quality, if you have a local discount-type tool store you can take a look at their lineup and see if you find something that looks stout enough to do the job.
There should be plenty of this type of tool on eBay, also.
If you have an Autozone nearby, they may have the tool to loan out, it'll cost you a deposit equal to the price of the tool but you get that back when you return it to them.
Pick up a new bearing at any local auto parts store. This is a "206" unshielded bearing with a lot of applications. Also known as "6206" and should run under $20 or thereabouts. Note that you could also use a shielded bearing but you'd have to pry out the shields on both sides.
If you have access to a hydraulic press, you can have the bearing pressed on. Just make sure the crankshaft is supported by the last counterweight at #6 cylinder. Never press thru the entire length of the crankshaft, it's possible to warp the crank.
If no access to press, you'll need to heat the bearing up to approx 215 deg F for 30 minutes or so (an old toaster oven is handy to have on the workbench but an oven will do nicely). Note: don't ever heat bearings above 250 deg F as they may be damaged by the high temps.
Clean & lightly oil the bearing area of the crankshaft. Using well-insulated gloves (thick leather works fine), remove the bearing from the oven and immediately 'slap' it in place on the crankshaft. Note that you've got little time from when the bearing actually aligns to the end of the crank to get the bearing fully seated on the crank. Hold the bearing in place for a few seconds and it'll have shrunk itself solidly onto the crank.
If you didn't get the bearing fully seated, you'll have to press it the rest of the way or very carefully tap it on using a chunk of pipe which fits around the end of the crankshaft and will bear solidly against the center race. Don't ever strike the outer race or you'll damage the bearing.
HTH...........ed
