1975 850 lower bearing

merc850

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Has anyone re and re'd this lower bearing without disassembling the powerhead like the manual says? 1975 Merc 850.
 

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chum1

Petty Officer 1st Class
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Apr 15, 2010
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359
Re: 1975 850 lower bearing

ha ha is r&r the same as remove and replace? took me awhile to figure that one out:) , there may be a way to pull that lower bearing but i've heard you have to press the new one on....that may be the the difficult part, looks like you have a clean crank, hate for it to be ruined.
 

Chris1956

Supreme Mariner
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Mar 25, 2004
Messages
28,340
Re: 1975 850 lower bearing

It should be a slip fit. See if you can hook it and pull it off the crank. The new one can be installed easily, using a 1/2 drive socket of the correct diameter.
 

emckelvy

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Jan 16, 2004
Messages
2,506
Re: 1975 850 lower bearing

You'd have to use a puller with jaws that would fit around/behind the bearing to remove it. It's pretty tight in there so you may have a rough time doing it.

Do Not drive the bearing back onto the crankshaft, that's a good way to ruin it.

Instead heat the bearing to approx 220 deg F then (with thick-gloved hands!) quickly install the bearing onto the (well-oiled) shaft. The heat will expand the bearing race I.D. ever-so-slightly and it's enough to allow a slip-fit over the crankshaft O.D. Note that as soon as that bearing hits the crankshaft surface it's gonna start transferring heat and will clamp down on the shaft pronto, so you've gotta be quick and decisive when you put that bearing on. You'll have just enough time to get the bearing 'bottomed' (or 'topped' in this case) to the crank's machined surface before it's shrinking.

I have an old toaster oven that works great for this, if you use one just don't plan on cooking your lunch in it afterwards!

http://www.lawrencepumps.com/newsletter/news_v03_i4_apr06.html

G'luck with the repairs. I've been wishing I could do the same to an upper bearing but I can't see any way to get it out other than splitting the cases. Have Fun!...........ed

p.s. a '6206' or '206' bearing is the correct replacement and should be available thru most auto parts stores (and eBay or your local bearing house) for much cheaper than the Merc dlr. Don't forget to replace your crankshaft seals and bearing cap O-ring!
 

merc850

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Jul 7, 2010
Messages
2,055
Re: 1975 850 lower bearing

Thanks for the advice; I have seen several 3 leg pullers that might fit at a local auto store. I would like to heat the bearing, to help with removal, with a propane torch but the ball retainer is made of nylon? The bearing itself has a lateral wobble but it rolls freely so I am still debating on removing.
 
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