Replacing Upper U-joint yoke & bearing - 84 Alpha One

[jeffbrinkerhoff]

I have read the factory manual, and have searched here. I was just hoping to get some advice and opinions:

I recently replaced all the bellows, gimbal bearing, etc. (After having done it just 3 years ago... cheap bellows degraded - used all quicksilver stuff this time). I discovered a small amount of gear lube in the bellows, coming from the upper drive shaft yoke.

I bought a new seal, and will beg/borrow or buy a tool to get the big retainer nut off. Most likely I will get a new stub yoke, and u-joints at the same time. But, once I do get it apart I am not exactly clear on what needs to be done to replace the seal.

Looks like there are two possible bearing setups. With or without the "small spacer", which have differing repair procedures.

So, here's the specific questions:

1) boating season is short here. Almost over, I just got the drive back on the boat, topped up the gear oil (was only a little down and not milky), and would really prefer to just drive it for the few hours we will probably use it this late summer (perhaps 5-10 more hours, freshwater lakes). Then pull the drive when I store it and r&r the seal then. Opinions? Check oil at every trip of course.

2) When I pull it - do I have to somehow mark the gear positions so the teeth match up exactly upon reassembly? If so, how? I can see how I could mark the "vertical" shaft, but how can I be sure to get everything exactly back to where it came out? How important is this?

3) The drive is an early 1984. Merc 120, 4cyl. What are the odds I have the easier "small spacer" setup? I do not have an in-lb torque wrench, but I could get one if I have to I suppose.

Any tips on this job? I see many posts saying its not a bad job at all. I would probably plan on getting a new short yoke, as its apparent that the u-joints and shaft are rusty (this happened before I owned it - its been rusty for as long as Ive had it, but is probably now worse).

I look forward to and value all opinions.

Thanks!
Jeff

 

[Bondo]

Re: Replacing Upper U-joint yoke & bearing - 84 Alpha One

Any tips on this job?

Ayuh,... You can find All the Answers up in the Adults Only section at the top of this forum,...
The Factory Manuals for your rig are in there....




edit; benchmark,...Posts: 23,000

 

[ziggy]

Re: Replacing Upper U-joint yoke & bearing - 84 Alpha One

i've done the deed. but only once and on a slightly older drive than you got. should be a similar, though not exact same experience for you. i only have that to reflect back upon so take what i say with a grain of salt so to say. i did have the small spacer so i got lucky. yers is newer than mine so i'm gonna guess ya won't be as lucky. you'll likely need the inch/lbs dial type torque wrench. another thing i was gonna be concerned with prior to finding i had the spacer was the need for a press to press the brg. back off, assuming ya over torque it accidentally.
as for your questions.
1. seems like a good plan to me. about the way i did it. granted you know you had water intrusion into the bellows. but you also know that's been cured by you with the new bellows. if water don't get into that area, it should also not penetrate the ft. seal of the drive as there's nothing but air in that area. least that's the way it's supposed to be.
2.i was lucky there too. i got the 1.65:1 ratio. so i was pre marked. from reading the book, your likely not marked. i would go to some trouble to mark them i'd think. the wear pattern is there from years of use. so i'd think ya'd want to go back exactly the same. fwiw. the marks on my gear teeth were nothing more that what looked like someone used an electric pencil, by hand, etching is some lines on the flat of the outside of the teeth. 2 on one gear, 3 on the other if i remember right. what to use to mark them with i don't know. maybe wipe them clean, count them up and mark with something like a sharpie? prior to taking the yoke out. when disassembled perhaps mark them with something more permanent so to be sure it don't wipe clean upon reassembly. maybe a carbide tip pencil for a line. only thing i can think of that might scribe them. i'd think ya wouln't want to disturb the metal to much on the teeth, even if it's on the end of the tooth.
3. gave ya my best guess above. and it's only a guess. kinda irrelevant though, as ya got what ya got. only reason to know prior to would be to gather up the proper tools. ya know them dial indicator in/lbs torque wrench's sure aren't cheap...

only tip i have is read the s/m real close. i read it over and over till i thought i understood what i needed to do, prior to doing anything. when i did the deed. i did it sentence by sentence from the book (oem service manual for my rig). anything that i didn't understand. i ask here on ye ol friendly iboats forum. had lots of good reply's too... if ya wanna see them, i think they're still in the archives. search me, posts i started, around nov. 07 i think. yep, just went and searched me. it's nov. 01 2007. stared with my ujoints and progressed all winter for repair....
good luck with your adventure...


bondo, congrats on 23k posts. ya've sure been an inspiration to me and have always trusted your reply's. thanks much for your help...

 

[jeffbrinkerhoff]

Re: Replacing Upper U-joint yoke & bearing - 84 Alpha One

Bondo, thanks - I have read the factory manual. It's not super detailed in this area, and like I said I wanted to know if anyone knew about when they switched to the "no little spacer" method (or if there is a date).

Ziggy, Thanks for the insight. I will probably just leave it as is for now and top up the oil before each use until the end of the season, then pull the drive and see how much oil is in the bellows. Over the winter I will pull the yoke and bearings and see how it goes.

I was not (am still am not totally) clear on how I can mark the gearset before removal. Once I remove the top cover, can I see the gearset in a way that I can mark both gears? Seems like once you pull on the yoke and the gears unmesh you'd never know for sure how they went together.

I would use a sharpie, then follow up with an electric pencil/carbide tip.

Thanks - and I did read your older threads. (I really did research!)

Jeff

 

[Rypye]

Re: Replacing Upper U-joint yoke & bearing - 84 Alpha One



Ayuh,... You can find All the Answers up in the Adults Only section at the top of this forum,...
The Factory Manuals for your rig are in there....




edit; benchmark,...Posts: 23,000

Sorry to highjack the post but I’m having some issues figuring out what yoke to use with my setup , I’m using a 3.0 bell and the mate for the inside of the boat and a alpha 1 gen 1 gimbal housing on the outside with the newer style rams , I have a mc 1 drive from a merc 888 I’m running a 292 with the 3.0 coupler I need to know if I should use the 8-1/8 or the 9-9/16 yoke I’m having trouble figuring this out any help would be much appreciated I have 3 drives to chose from but I really want the 1.50-1 the boat is only 15ft thank you