1982 Mercruiser 470 I/O stern drive questions (w/photos)

Pink Floyd

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Feb 16, 2014
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One more issue...

I pulled the lower unit (I'm expecting to rebuild the water pump, due to afore mentioned stupidity), during removal some additional pieces of the shutter dislodged which prompted me to remove the upper unit in search of any other issues. I have attached photos of what I've found. My initial concern is that there is gear oil in the drive shaft receiver bellow. Is that normal? Next, the U joint on the drive shaft is rusted. It works and moves perfectly, and feels strong, but has definitely seen better days. I'm not sure what I thought I would see on a driveshaft that has never seen daylight in 32 years. What do you guys think of the photos and where I should go from here?

Questions:
1. Gear oil in driveshaft receiver bellow...normal or evidence of a bad seal somewhere?
2. Corrosion on U joint...run with it for now or replace? Why?
3. Is there a gasket/seal kit that I should invest in, and if so which one? I know I'm investing in a stern drive gasket, but what others would be good to replace since I already have it off.

I have not cleaned the parts yet, I just pulled them apart to begin the restoration process.

Driveshaft receiver.jpgLower unit.jpgUpper unit and U joint.jpg
 

Bt Doctur

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19,093
Re: 1982 Mercruiser 470 I/O stern drive questions (w/photos)

upper yoke seal leaking gear oil into housing, white crusty stuff is evidence of gasket failure allowing some water into that area.
A dislodged water inlet o ring or improper gasket mounting will allow water in there too. Might want to invest in a new shift cable at this point. Also inspect the boots for signs of rot or extreme dryness.
 
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Pink Floyd

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Re: 1982 Mercruiser 470 I/O stern drive questions (w/photos)

upper yoke seal leaking gear oil into housing, white crusty stuff is evidence of gasket failure allowing some water into that area.
A dislodged water inlet o ring or improper gasket mounting will allow water in there too. Might want to invest in a new shift cable at this point. Also inspect the boots for signs of rot or extreme dryness.

Thanks,

It didn't fell right when I saw that mess. Thanks for confirming my thoughts...
 

wrench 3

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Re: 1982 Mercruiser 470 I/O stern drive questions (w/photos)

To check the "U" joints, put a slight rotating torque on the shaft while flexing each joint through its travel in both directions. If they move smoothly and freely, grease the fitting in the center of the trunnion and re-use. The drive should be removed to grease the "U" joints and the splines every couple of years. Not leave it in the dark for 32 years.
To reinstall the drive you could use a Sierra gasket kit part #18-2614.
 

Pink Floyd

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Re: 1982 Mercruiser 470 I/O stern drive questions (w/photos)

Awesome advice, thank you very much. I appreciated the gasket kit # as well.

Thanks
 

Pink Floyd

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Re: 1982 Mercruiser 470 I/O stern drive questions (w/photos)

How do I remove the yoke retainer without purchasing an expensive wrench that only works on it!?!? Any cool tricks? Or should I try the local autoparts store to see if they rent a "special" tool that will accomplish the task?

IMG_5923.jpg

And how do I get this website to stop logging me off?
 
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MikDee

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Re: 1982 Mercruiser 470 I/O stern drive questions (w/photos)

I know you certainly got your work cut out for you, and you will be fine taking it one step at a time, but One more thing that's important, and sometimes goes unnoticed, is make sure the tiny hole on the flat side of the lower gearcase ,with the o-ring on it between the upper, & lower housing, is not clogged or blocked. It is the main gear oil circulation between the upper, & lower gearcase.
 

tazrig

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Re: 1982 Mercruiser 470 I/O stern drive questions (w/photos)

Pink,

here is a link to the Mercruiser service manu@l for your drive.

Boatinfo - Mercruiser Service Manual nr. 4 - 1978-1982 - MC 120 to 260 Sterndrives

As far as the tool goes you might try an auto parts store but I think that is a merc specific tool. I would try going to a boat yard first and see if you can "bribe" a mechanic for $10 or what ever amount to use the tool on premisses. Male sure to drain the oil first so you don't have a mess and you might want to hit it once or twice with some penetrating oil as it hasn't been apart in 32 years. :facepalm: I agree with BT, now would be the time to replace the lower shift cable. I can't believe there is much left of the rubber bellows either, while you have it apart you might as well... If you call iBoats at: 1-800-869-1686 and tell them what drive you have they stock all the parts you'll need including the gaskets to the fill and drain holes that should be replaced every oil change to prevent water intrusion that everybody forgets about.:D


To stop getting logged off click the "remember me" box next to or under the password box the next time you log on. If you log on and don't do anything for a while (1/2 hour I think) the system will log you off anyway. You also need to have your cookies on for at least one log on so the system will remember you name and password.
 

wrench 3

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Re: 1982 Mercruiser 470 I/O stern drive questions (w/photos)

It skipped my memory that you had the upper and lower units separated. There is a seal on the oil passage between the two units, Siarra part #18-2944. But while you have it apart you should install a water pump impeller kit part #18-3217. It includes the oil passage seal.
If you want to order the parts from this web site, just punch the part numbers into the product search window. It will get you to the right section.

What do you know! The water pump kit is on sale right now for $25.97.
 
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Fishermark

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Re: 1982 Mercruiser 470 I/O stern drive questions (w/photos)

I don't know anything about your previous post you mention, but if you are planning on resealing the top, then you will need the tool to remove the big nut. You will not find it at any auto parts store... but you can find them on ebay and other aftermarket suppliers for not too much money. You might be able to rig something to remove it, but in order to reinstall it you will need to torque it to something like 200 ft lbs. (There is a chart that takes the length of the tool into consideration, so you will need to look that up in the service manual.

Then, if you have a newer style of drive, you will need to set the rolling torque on the upper shaft. Achris has a good video on doing that in the stickies at the top of the page.
 
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