Upper seal on alpha 1

[NHGuy]

I just pressure checked my drive and got a slow leak. Soaped the seals and got bubbles behind the double universal joint at the top drive seal.
I did some reading and it looks as if it is a doable job. Am I right to think the only special tool is the spanner for the big retainer?
Looks like I need to dissassemble and inspect to see if the bearings are good. If they are I get to keep the original shims, change out the seal, and set the preload, right?
Are there any other things to do while in there besides inspect and reseal the drive top cover? I am already getting familiar with the u joints, bellows, alignment and external stuff for the drive-just asking what to do inside.
I can see that it's too much money to buy the tools to set up the guts properly. Are there any pitfalls to avoid?
On the bright side, I have til April to do this!

 

[Bt Doctur]

Re: Upper seal on alpha 1

When replacing the seal also check the yoke for grooving. just a new seal may not be enough.depending on your setup, either set the rolling torque or just torque the nut to spec.

 

[rad1026]

Re: Upper seal on alpha 1

I am going through the same thing, "Please tell me my outdrive isn't toast". It turns out I'm looking at new bearings. I had water intrusion and it must have been like that for a couple months.

 

[NHGuy]

Re: Upper seal on alpha 1

Rad I have been following your thread...I'm still waiting for my spanner and parts. Hopefully no damage inside my drive. My fingers are crossed.
My drive oil has come out perfect in the 3 years I have owned this boat. I use Merc high performance drive lubricant.
It came out looking right this year too, but I made up a tester and found I have a very slight leak in the upper seal. It takes a 5 or 10 minute period to lose 4PSI, and even less to lose vacuum.
So I figure I'll give an ounce of prevention to eliminate a pound of cure.

 

[rad1026]

Re: Upper seal on alpha 1

okay, good for you. My oil did not come out ok. Stupid, lazy me. I usually check my gear oil several times during the season, just didn't do it this year. Might have saved myself some money had I not been so lazy. Always learn lessons the hard way I guess. You saw the pictures I posted, so you can compare what you see inside your drive with those and decide if you need to replace anything. Let us know how it turns out. I'm going to talk to my local shop today and get their opinion on the final re-assembly of my drive. Hopefully they will work with me.

 

[NHGuy]

Re: Upper seal on alpha 1

OK, so today I pulled the upper gear & seal assembly and found the yoke is scored where the seal contacts it. If I change the inner short yoke do I need to reshim that shaft? I think it looks like I should.
If I do maybe Rad & I can split the cost of a shimming tool for the top end.

 

[rad1026]

Re: Upper seal on alpha 1

well, I took all my parts to a Merc mechanic last week and I haven't posted the results because most people in here won't agree with what the mechanic said. I posted pics of my bearings, races and yoke. A couple responses were very extreme saying I'm lucky the bearings were still together and hadn't exploded inside the drive. The mechanic looked at my bearings and said put them back in and run it. He said if it was his boat he would not hesitate to run those bearings, with the horsepower I'm running and the shape of the bearings they will probably last another 6 years. He also said that 99% of the time the initial shimming is all that is required. He basically said that the cases cannot be manufactured to such strict tolerances because of the aluminum material, but that the bearings are made to very tight tolerances, so he told me to replace all the upper seals and showed me how to re-press the bearing on to the drive gear and how to set the rolling torque. I took my drive shaft to a drive line shop just to have them look at my u-joints. They said they were fine. Told me that those were GM u-joints that they sell for $25.00, $45-50 each if you buy them from a marine supplier. So I know its my call. I don't think the guy was telling me to put back in bad bearings so I would blow up my drive and come to him to fix it. So I am replacing the yoke and all seals, new lock nut and washer, new gimbal bearing and seal and new water pump kit.

Let me know what you decide to do NHguy

 

[dubs283]

Re: Upper seal on alpha 1

If I change the inner short yoke do I need to reshim that shaft?

no

you need to re-shim only if you replace bearings/gears

get an alpha upper seal kit and re-seal the whole upper, replace the water pump and base assy in the lower and pressure test

a vacuum test does no good on the upper half of the drive, the yoke seal does not hold vacuum

 

[NHGuy]

Re: Upper seal on alpha 1

I have a yoke coming, already have the seal that leaked and the needed o rings.

I am thinking about checking the clearance even though dubs says don't waste my time...I'm being anal cause that's how I'm wired.

Dubs. Yup agreed on the vac test. The upper seal blew bubbles under 14 psi & was hard when removed.

 

[achris]

Re: Upper seal on alpha 1

+1 for not having to re-shim, if it's just the yoke you're replacing. I know it's a bit late now, but when I have a yoke with a groove I just set the new seal down a further 20-40 thou. That puts the seal onto a new area of the yoke and it's just like having a new one... You'd get another 10+ years of use before having to replace the original yoke....

Rad... your call, but those bearings have definitely been wet and the hard plating has been penetrate, and regardless of horsepower they are at risk. I have worked on quite a variety of equipment in a variety of different industries, and one thing that is common throughout is that not replacing damaged bearings will only lead to tears. I see entire hydraulic systems contaminated with the remnants of a bearings that grenaded in subsea thrusters. Those thrusters are 5hp! I've pulled bearings (the remains of) out of electric winches that are less than 1/2hp. There is no 'safe level' of power for a damaged bearing. Just look at a trailer wheel bearing when it explodes, and there is no power being transmitted. I'm not trying to scare monger you, but is it worth the risk? A few dollars now, or a thousand and change later....

Chris.......

 

[rad1026]

Re: Upper seal on alpha 1

yeah, chris I'm still thinking about it I haven't made a final decision yet. I'm in for $165 now, really what is another $100. I may go ahead and order the new bearings next payday.

 

[rad1026]

Re: Upper seal on alpha 1

I decided to replace the bearings. I ordered them this morning. Tapered bearing set and upper shaft.

NHguy, how is it going with your drive? Did you get it back together?

 

[NHGuy]

Re: Upper seal on alpha 1

My sealing surface on my yoke is really cruddy so I ordered a new yoke. It hasn't showed yet, I think it's coming via Mars.
I see how I shouldn't need to reshim the input shaft cause in my situation the gear-bearing-seal cluster doesn't change length. I DO however have that shimming tool, so I will check it. If you want to use it when I'm done maybe we could work that out.
It's no big deal that I don't have the drive reassembled, it's dead of winter here. I won't have a chance of launching til at least April, usually May.
Everything else is here though.

On another note, I am in a friendly argument with one of my co workers. It's whether to use a hammer or a press to change universal joints. I say press them. Who says to bash?

 

[dubs283]

Re: Upper seal on alpha 1

I am in a friendly argument with one of my co workers. It's whether to use a hammer or a press to change universal joints. I say press them. Who says to bash?

either way will work

a hammer is easier and faster

just be sure to grease the joints first, helps keep the needle bearings in place when the caps are off

 

[achris]

Re: Upper seal on alpha 1

...On another note, I am in a friendly argument with one of my co workers. It's whether to use a hammer or a press to change universal joints. I say press them. Who says to bash?

I've used both, I prefer press...

 

[ziggy]

Re: Upper seal on alpha 1

myself, i generally like finesse over force, if i can. so press. i even went so far as to get one of them mercruiser tools (not too expensive) to make the job easier yet. and the press and the tool did make the job easy...