Lower unit Driveshaft rough where seal rides

mikmic2

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Jan 31, 2006
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I have a 1972 Mercury 80hp. The driveshaft is rough where the seals ride. Originally I thought it was good, but now I see that it is pretty good except on one side it has a recess right where the seal rides. <br /><br />I have heard about taking it to the machine shop and having it filled and smoothed. <br /><br />1. Is this an expensive process?<br /><br />2. Is there a lock ring around the driveshaft underneath the pinion gear that needs to be removed? <br /><br /><br />Somebody else told me about some sleeves. A couple of questions. <br /><br />1. Where do you get these sleeves?<br /><br />2. Do you have to use different seals now? I mean oversized, because the sleeves are a tad larger then the shaft?<br /><br />3. What do you put between the sleeve and the shaft so it does not leak there?<br /><br />As always, any and all help will be greatly appreciated. <br />Thanks<br />Mike
 

Laddies

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Re: Lower unit Driveshaft rough where seal rides

To have the shaft repaired it will have to be removed from the unit, this means removing the carrier, prop shaft and rev. gear to install a seal sleeve measure the seal surface dia. go to a auto parts store buy a sleeve, you will need a peice of pipe long enough to tap the sleeve in place, don't try to cut the installing flange off like the instructions say to, you will ruin the sleeve it don't hurt a thing where it sits reassemble and you should be fine
 

roger3645

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Re: Lower unit Driveshaft rough where seal rides

Billy I installed a speedi sleeve two weeks ago. I wasn't able to find a sleeve at an auto parts store. They said they only sold them by application and not by size. I was able to pick one up at a bearing shop. You have to measure the diameter of the shaft and get one by size go to http--www2.vsm.skf.com and you'll find a size chart. My 1973 85 hp took a .984 sleeve.
 

roger3645

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Re: Lower unit Driveshaft rough where seal rides

Oh! you do not have to change the seal.
 

mikmic2

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Re: Lower unit Driveshaft rough where seal rides

You don't have to put nothing between the seal and shaft to seal it up? That's just wierd. LOL <br />I remember many moons ago doing that to a front seal on an old 350 Chevy, but I don't remember much about it. I do seem to recall ruining the first one however, that might be related to the installation flange.<br /><br />I've had the bearing carrier and stuff out enough, but I've never had the driveshaft out. I suppose I have to buy another specialty tool to get the driveshaft out? My clymers is rather generic when it comes to lower units. Do I need that long snap ring removal tool? What holds the pinion gear to the end of the driveshaft?<br /><br />Thanks Laddies and Roger.
 

roger3645

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Re: Lower unit Driveshaft rough where seal rides

There is a nut at the end of the pinion gear. Remove the nut and the pinion will come off. Then just pull out the the driveshaft, there's no snap ring. That speedi sleeve will run you about $35.00. The part number for mine was 99098 or 99813. I got a great seal on the LU after adding the speedi sleeve.
 

roger3645

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Re: Lower unit Driveshaft rough where seal rides

Billy bewteen the shaft and the sleeve there is no play. The sleeve fits tight over the shaft. Using the installation piece that comes with the sleeve you have to use a rubber hammer to tap the sleeve over the shaft. That's why you need a good diameter measurement of the shaft to find the right size sleeve.
 

mikmic2

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Re: Lower unit Driveshaft rough where seal rides

I just measured my shaft, and I came up with .955 where the seal rides. Down lower the shaft is .960. <br /><br />The only problem is I am between sizes. They have a sleeve .940-.945, then the jump up to .966-.970. So I thought I better go with the larger size, the .966-.970. This also comes in either a .313 tall or a .625 tall.<br /><br />Roger, it looks like you bought the one that was only .313 tall. My seals back to back is taller then that, which means I would only have the bottom seal riding on the sleeve. I was thinking about getting the one that is .625 tall. Do you remember if you thought there was enough room for one that tall. It sure looks like there would be nothing in the way. <br /><br />It also looks like you have to have the flange down towards the lower unit, is that what you did? It looks like it says the tool that comes with it will only knock it onto a shaft 2 inches long. Did you have to remove end of the tool so it would slip over the shaft, and tap in a circular motion? <br /><br />If you would be kind enough to give a short explanation as to what it entailed and what you learned from your experience, I would be greatful.
 

Laddies

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Re: Lower unit Driveshaft rough where seal rides

Bill thats what I ment when I said get a peice of pipe I use a peice of copper pipe about 30" long if the shaft is real bad I use some loctite on the old seal surface
 

roger3645

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Re: Lower unit Driveshaft rough where seal rides

Billy if .625 was available for mine I would have used that size also. Yes flange down toward L/U and as Laddies said don't try to remove the flange after you install the sleeve. Also the installation tool that came with mine had a hole in it so it slid right over the driveshaft. If the tool does not have a hole then use the copper pipe suggested by Laddies sounds like it'll work great. Also if your sleeve is a bit large then use loctite or a metal epoxy between the sleeve and driveshaft.
 

Mercr

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Re: Lower unit Driveshaft rough where seal rides

Originally posted by BillyBobBass:<br /> I have heard about taking it to the machine shop and having it filled and smoothed. <br /><br />1. Is this an expensive process?
$190, according to my shop. That's to do a SS electro-plate. 'Hard to figure the labor part - they're doing a full rebuild. The sleeve sounds like the way to go, in your case.
 

mikmic2

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Re: Lower unit Driveshaft rough where seal rides

Mercr, I think your right. The sleeve was about $30.00. Although I won't know full cost until this Friday. They just said about $30.00.<br />Thanks
 

mikmic2

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Re: Lower unit Driveshaft rough where seal rides

Well I recieved the speedi sleeve and cleaned the shaft up and had my lock tite sleeve retaining glue or whatever it was all ready. I tried to slip the sleeve on and no go. <br /><br />I took out my fine craftsman calipers and realized that my calipers catch and skip in a spot. It turns out I really need the same sleeve as Roger used. I need the .985. Bummer. Should of checked out my calipers but I've used them on many things that require a close tolerance and they worked great. It looks like I will have to get a new pair of calipers, but it appears I need the same as roger, a .985.<br /><br />I didn't even scratch the speedi sleeve as I could see as soon as it hit the fat part that this wasn't going to tap on there. I sure hope they take it back. <br /><br />The good news is I only payed about $27.50 for it. :) <br /><br />I will let you know how it turns out. <br /><br />Are there any other companies that sell speedy sleeve longer then a 1/3 of a inch? In order for it to ride on both seals it needs to be closer to 2/3 inch long. Otherwise it looks like one good seal is better then what I have now. LOL<br /><br />Thanks for your help, and I will keep you updated.<br /><br />Roger, does yours appear to be still keeping the water out with the shorter sleeve like I think I am going to have to use?
 

roger3645

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Re: Lower unit Driveshaft rough where seal rides

Yes, I have had the boat in the lake since installing the speedi sleeve. I'm very pleased with the seal. Good as new. I'm sure they'll let you excahnge the sleeve as long as it's not damged. Good Luck.
 

mikmic2

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Re: Lower unit Driveshaft rough where seal rides

Thanks for the quick reply roger, I will let you know hot it goes.
 

exracer

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Re: Lower unit Driveshaft rough where seal rides

Thanks for the quick reply roger, I will let you know hot it goes.
I've got a 1969 mercury 500, 50 hp..any one know the speedy sleeve size? Or the shaft diameter, where the sleeve would fit....
 
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