Replacing Lower Drive Shaft Seals in Upper Housing of Mercruiser Alpha 1

[raglover]

I just removed the lower unit from a friend's 1986 Alpha One stern drive (2.5 L) to find that the o-ring that fits on the top of drive shaft remained in the upper housing. I looked up in the housing to see not only the o-ring but also the remains of a spring loaded rubber oil seal.<br /><br />Looking in the Clymers manual it looks like there are two seals under the pinion gear that drives the lower unit drive shaft. Question is can these be replaced from the bottom of the upper housing. Looking up into the housing I see what looks like the metal case of the lower most oil seal, is this correct? What type of seal is located above this--should I just plan to replace both? <br /><br />As always thanks for the help

 

[lowshovel1]

Re: Replacing Lower Drive Shaft Seals in Upper Housing of Mercruiser Alpha 1

this link may help ya http://www.mercstuff.com/howdoi.htm

 

[djvan]

Re: Replacing Lower Drive Shaft Seals in Upper Housing of Mercruiser Alpha 1

Yes there is a seal in there and yes it can be changed from the bottom side. I've done it before. Don't know if it should be, but I have done it. The lip of the seal faces out (keeps water out). I don't remember if another seal is behind that or not. My guess would be yes, with the lip facing in (keeps oil in). I'm not by my manual right now to look. If you don't have a manual you should get one they are very handy.<br /><br />DougV>

 

[qystan]

Re: Replacing Lower Drive Shaft Seals in Upper Housing of Mercruiser Alpha 1

There are 2 seals as described by djvan. Yes, they are the type you described.<br /><br />The inner has to be changed from the inside.<br /><br />You can change the outer. Pry it out with a screwdriver and use a socket or something similar to install the seal. The lip faces out to keep water out.<br /><br />The problem you got comes from the driveshaft o-ring damaging the oil seal during installation. Change the outer seal, pack the space behind it with grease. Install the lower unit without the o-ring. The seal in the housing will keep water out of the splines area.