Oil seal replacement for mercruiser drive

[water_rat03]

I have a few quick questions on the oil seals in my drive. I am looking at a 1976 Mercury 165hp with the older style drive. Type R I believe, can get the serial # and post if it will help.
When I got the boat the engine had just been replaced brand new. I replaced the Gimble bearing, bellows and water pump in the drive.

Last time on the lake i filled the drive with oil, pumping the oil in from the drain screws as directed. After an hour of putting around the lake the drive would be almost out of oil. So oil is leaking out but no water is coming in.

Now I have 2 questions.
1. From you that have worked on mercury engines and drives, what is the best service manual to buy for this boat? A friend of mine has a Clymers (I think) that I have borrowed. Before getting it ready this spring I will be buying my own manual.
2. I am assuming the prop shaft seals are bad. This boat sat for several years before I got it. How hard are the seals to change? Are any special tools required to do so?
I have 20+ years of experience as an auto mechanic, but am thinking beyond the basic mechanical abilities, automotive experience will not be much help on the boat.

Thanks in advance for the information.

 

[Bondo]

Re: Oil seal replacement for mercruiser drive

Ayuh,.....

#1),..... This manual Right here is the Only 1 worth reading,....

#2),..... Before I just went Rippin,+ Tear'n,......
I'd do a Pressure Test to See where it's Leaking.......

See #1 to find out How to do it.....

 

[Haut Medoc]

Re: Oil seal replacement for mercruiser drive

I would pull the drive & look in the bellows, most likely it is the yoke shaft gone bad.....
The only way to isolate the leak(s) is to pressure test the drive.....
The prop shaft seal is not too hard, but you will need the bearing retainer wrench $60 or so & a 3 jaw puller.....
You will also need to inpect the seal area on the prop shaft....
The yoke seal is not that hard either, again you will need to inspect the seal surface.....
Oh, chuck the Clymer's btw, it is only suitable for outhouses or to start the BBQ.....
& get yerself a Merccruiser Manual #2.......​

 

[water_rat03]

Re: Oil seal replacement for mercruiser drive

That sounds like good advice.
I got an old bicycle pump with a guage on it. I read somewhere on here how to make a pressure tester out of one of those.
Would the yoke seal leak that much of the oil out? Where would the oil go when it leaked out of there?

Was kind of thinking of pulling the drive so I could inspect the bellows, probably go ahead and replace them as preventative maintenance.

The local boat shop quoted me $200 to $250 to check the drive and replace the seals. Maybe will go with them. Not a bad price to pay knowing that everything will be done right.

Thanks for the information.
And thanks for the link to the mercruiser manual, it looks like that has all of the information I should need until I get a book ordered.

 

[ziggy]

Re: Oil seal replacement for mercruiser drive

if yer drive serial # is between 3780850-4890459 ya need mercruiser service manual #2, c-90-71707. same book for yer engine if serial # is between 3774865-4884834...

yes to what the guys are saying about the pressure test... it'll help ya locate your leak. i wouldn't just assume where the leak is at. yep, ya can make one out of a bicycle pump. here's what i put together....

not a pretty site. but it works. the white thing is a self bleeder vacume pump for doing auto brakes. the other is the bycycle pump w/ gage and a merc. gear lub pump end on it to connect it to the drive..... best i understand. a drive should hold 15psi forever and around 5hg of vac.

good idea to pull yer drive and do some inspecting of the bellows.... ya can lub the ujoints, inspect the gimble brg. and lub the coupler while your there. before put it back ya check the alignment also. that'll be your first mercruiser specialty tool that ya will want to get. there seem to be many. specially if yer tearing into a drive........ if ya got rust on yer ujoints. ya've had water intrusion at some point. this would warrent checking the ft. seal of the drive. it keeps lub in, but not water out. water also premotes rust on the yoke which eats up the yoke seal. ya say ya've done a water pump. did ya put the quad ring back in between the drive upper and lower when reassembling? or the seals for the drain and fill screws? did you remove the old seals before using the new ones on the drain and fill screws.... just a couple of ideas. specially easy to check the drain and fill screws for their seals.

as for yer clymers..... well, i hate to admit it. but i got one too. it resides in the boat as a last resort for troubles on the lake.... or like everyone else says. to help start my campfire that night.... use a merc manual...

 

[Bondo]

Re: Oil seal replacement for mercruiser drive

The local boat shop quoted me $200 to $250 to check the drive and replace the seals. Maybe will go with them. Not a bad price to pay knowing that everything will be done right.

Ayuh,......

I don't know where you live, or the going rates there,....
But,....
I'd Bet double or Nothing that the price quoted Might get you the answer to Where it's leaking,.....
But there's No way in 'ell it'll get Fixed for that price......
Unless by chance it is Just the propshaft seal,+ they don't bother to even pull the drive....

Just a set of bellows,+ a lower shift cable Kit will cost nearly that much......

 

[water_rat03]

Re: Oil seal replacement for mercruiser drive

Thanks for the added advice.
I replaced the seal ring your talking about with the water pump replacement. I also removed the gaskets and replaced with new on the oil plugs. Actualy I got new plugs, the old ones had been mangled with vice grips prior to my owning the boat. Looked like someone did not have a screwdriver so they used pliers. For 50 cents I just replaced them.

Your pressure and vacuum testers were what I was thinking of making. I can see a little oil dripping from around the prop so that seal is definately suspect.
And the Clymers manual is not mine, only one I borrowed from a friend. I felt like there should be a better one out there. Will buy the merc manual soon.

Thanks again.

 

[water_rat03]

Re: Oil seal replacement for mercruiser drive

Bondo that is a good point too. When I called the dealer I asked for an approximate cost for the PROP SHAFT SEAL. So I will have to keep that in mind if I decide to take it in for repair. When I spoke with the mechanic he did say that was the price for the prop shaft seal, but he said he would have to test it and see what was going on with it.
I have saved enough of my tax return back so if I decide to go to the shop with it I can do what needs done. Still might be worth the money to hava it done right.

Thanks