Difficulty installing Alpha 1 lower unit

[model14]

I have read the repair manual and watched YouTube videos. It all looks so easy, but it is whipping my butt! The drive shaft will not engage the upper unit no matter how much I turn the drive shaft (lower shift shaft in forward gear, turning the prop shaft counter clockwise), I get a "clunk" and it won't go any further. It is just short of the lower unit side studs poking through the upper unit holes. I am pretty sure it is not the water tube or the shift shaft (too hard of a clunk). The clunk is metallic and comes from the area of the drive shaft tip. What could be the problem?
Thanks,
Richard

p.s. This is the same lower as I removed for water pump replacement.

 

[ktbarrentine]

Re: Difficulty installing Alpha 1 lower unit

What year/model is your drive (i.e, is it pre 1991, or gen II?)? Sounds like you are attacking this with the upper unit still on the boat. If pre 1991, it may be that you have something (like an old O-ring) up in the splines of the upper unit drive shaft (where the lower drive shaft connects to the upper). Being "pretty sure" the water tube is lining up is not being "absolutely sure". May be time to take the upper off and then attempt the matting, since then you can get a good look at the drive shaft as it goes into the upper and the water tube as it enters the pump tube. You can also then turn the yoke shaft to try to line up the splines, instead of turning the prop. Just thoughts at this point.

 

[model14]

Re: Difficulty installing Alpha 1 lower unit

The sterndrive is a 1988 Alpha 1. This is a restoration project. I pulled the lower for water pump replacement. I pulled the upper to grease the u-joints and replace the gaskets and water passage O-ring. I chose to install the upper first rather than mating the upper and lower first. This decision was based solely on weight handling concerns. I will closely inspect the upper unit female splines for interference, as you suggest. I had done a cursory look and saw nothing. I greased the water pump housing output tube lip to see if the upper tube is engaging. It is. I am getting the clunk and stoppage just before the upper and lower shifter shafts engage. I may have to take off the upper as you suggest, but I sure hate to!
Richard

 

[Bondo]

Re: Difficulty installing Alpha 1 lower unit

The sterndrive is a 1988 Alpha 1. This is a restoration project. I pulled the lower for water pump replacement. I pulled the upper to grease the u-joints and replace the gaskets and water passage O-ring. I chose to install the upper first rather than mating the upper and lower first. This decision was based solely on weight handling concerns. I will closely inspect the upper unit female splines for interference, as you suggest. I had done a cursory look and saw nothing. I greased the water pump housing output tube lip to see if the upper tube is engaging. It is. I am getting the clunk and stoppage just before the upper and lower shifter shafts engage. I may have to take off the upper as you suggest, but I sure hate to!
Richard

Ayuh,.... Put the water tube into the upper unit, 'n guide it into the pump housin', not the other way 'round,...

Ya could be havin' the water tube bumpin' on the water pocket cover,...

 

[model14]

Re: Difficulty installing Alpha 1 lower unit

Bondo,
Already doing that. Water tube is not the problem.
Richard

 

[cr2k]

Re: Difficulty installing Alpha 1 lower unit

Is the shift shoe and shift selector in Forward Gear?

 

[model14]

Re: Difficulty installing Alpha 1 lower unit

Is the shift shoe and shift selector in Forward Gear?

Yes. I have been careful to do that.

 

[Fishermark]

Re: Difficulty installing Alpha 1 lower unit

At this point I guess I would suggest removing the water tube completely and see if you can install the lower. If it still "clunks" and will not engage, then at least you have eliminated one possibility. Same thing applies if it goes up and in smoothly, then you will at least have discovered what needs to be addressed.

 

[model14]

Re: Difficulty installing Alpha 1 lower unit

This was found floating around in the female coupling of the upper unit. Where did it come from? It is not the O-ring on the lower unit shaft. It looks like a bearing seal. It was just loose in the coupling. We pulled it out and got the shaft to go home, reluctantly though.
Thanks,
Richard

 

[Bt Doctur]

Re: Difficulty installing Alpha 1 lower unit

Really should replace the seal , it should not interfere with mounting.

 

[stonyloam]

Re: Difficulty installing Alpha 1 lower unit

It came from the upper. It is an oil seal for the driveshaft. The metal outer part of the seal is still up there. Easiest way to remove remnants is to reach up with a long screwdriver and wedge it out. Am pretty sure it is #10 here: https://www.mercruiserparts.com/Sho...br=80&bdesc=DRIVESHAFT+HOUSING+AND+DRIVESHAFT
Without the rubber seal in place to guid the shaft you might be hitting the metal part of the seal?

 

[model14]

Re: Difficulty installing Alpha 1 lower unit

Can I replace the seal without getting into the upper gearbox? If I leave it out, I guess I can look for water in the oil. If that happens then I have to redo the upper unit. Ouch, expensive!

 

[ktbarrentine]

Re: Difficulty installing Alpha 1 lower unit

That is most likely the lower of the two seals in that area. This seal basically is there to keep water out of the splined area and keep grease in. Will you get water in the upper/oil? Maybe, but the upper seal is there to prevent that. You really need to replace that grease seal, however. It is there for a reason. And leave the o-ring off the shaft that goes through there. It most likely was the cause of the damage to the grease seal in the first place (Achris taught me well). Later drives do not have that O-ring, or the o-ring groove (a likely place for a shaft break, too.)
Yes, you can replace the seal without getting into the upper (i.e., you replace it from below), but it is STRONGLY recommended to pull the upper off the boat and invert it so you can you work on this from above on a workbench and do it right.

Good luck! This is a common malady with that vintage alpha-1.

(and I was close to being right in my first response, as I thought it may have been the O-ring which was floating around up in thos splines. That is what happened to me....)

KB

Also, as to the speculation of pending water damage, caused to the upper due to water intrusion as you mentioned as a possibility, you would possibly be looking at a whole new drive.... particularly if the damage is metal bits coming off the gears/bearings, as these will migrate to the lower and it would be just a matter of time before the lower is destroyed, too. Dont you just love these drives!!! (I do).

 

[model14]

Re: Difficulty installing Alpha 1 lower unit

This is a 1988 ThunderCraft 162 Regency restore, a boat with beautiful lines, in my opinion. I am just trying to get to the point where I can run the motor under power and make sure it is in good condition. If the motor is okay I will go back into the drive for more work.
Here is a picture of the boat:

 

[Tail_Gunner]

Re: Difficulty installing Alpha 1 lower unit

Well dont feel bad..i can drop a volvo drive and reboot it in 15 minute's....I had to take a alpha drive to a shop for reinstall...so be it....merc drive's are for the stunted suvaunt's....

 

[bspeth]

Re: Difficulty installing Alpha 1 lower unit

Goes in with the open end facing up just tap it in.

 

[stonyloam]

Re: Difficulty installing Alpha 1 lower unit

Yeah, I'm with KT, pull the upper and do it on the bench. Same thing happened to mine, was a pretty easy fix. Yeah every year that outdrive gets a little heavier. I built a stand on wheels for mine, makes a world of difference. Search for the outdrive stand thread in the Adults only some ideas. God luck.

 

[model14]

Re: Difficulty installing Alpha 1 lower unit

Well, I took your advice and pulled the upper to install the seal. I promply ruined it! I just couldn't get the seal to go in straight. It finally jammed/cocked so bad I had to ruin it to get it out. I ordered 2 more on ebay for $6 each and free shipping. LOcal dealer charged me $14 for the one I ruined. I got to be thinking how to seat that seal without screwing up. It is a very tight fit. Help!
Richard

 

[Bt Doctur]

Re: Difficulty installing Alpha 1 lower unit

Use a 1 inch , 1/2 inch drive socket with a long extension inserted "backwards". into the socket end not the flat end where you would normally put it.
set seal in place and use the flat part of the socket as a driver to seat it flush.

 

[model14]

Re: Difficulty installing Alpha 1 lower unit

Goes in with the open end facing up just tap it in.

Open end faces up as in to the top of the drive?