Upper Locked Up

[Stamey]

My Alpha One, SN A670521, was pulled to look at the gimbal. Now I have found that the upper unit will not turn in either direction. It worked fine last year, except for the roaring when the engine was running, which I suspected was the gimbal bearing. I split the lower from the upper and put the upper in a vise and took a 14" pry bar to it, in the drive shaft yoke. It doesn't want to move at all, in either direction. I do not have a 12 point 3/8 socket on hand to pull the top cap off, but I'm going to try to get one of those tomorrow.
Is there anything I could be missing here, before I tear into this thing?

Thanks,
Chris

 

[Bondo]

Re: Upper Locked Up

Ayuh,... How much metal, 'n crud was in the drained oil,..??

How much oil Was there,..?? Full, or Not,..??

 

[Stamey]

Re: Upper Locked Up

I saw only drops of oil when I split the cases. It was laying on its side, drain and vent holes up, so I do not know what the oil level was. The initial job was examine the gimbal so I had not checked or drained the gearbox yet.
I can also say though, that I did have the engine running, albeit for only a few seconds, to make sure it fired up, about 3 weeks ago.

Thanks,
Chris

 

[dubs283]

Re: Upper Locked Up

did you drain and replace the gearlube in the fall during winterizing?? or at least check it??

you will need that 3/8" 12 point socket to get into the upper, i guarantee that is is destroyed if you cant turn it with a breaker bar and no oil came out when you split the halves

you would be best set to replace the entire upper half of the drive

 

[Stamey]

Re: Upper Locked Up

I got the socket this morning and popped the cap off the top. There was almost no gear oil in the upper, and a little bit of water. I cleaned it it with carb cleaner so I could see the gear teeth clearly. The gears seem to be pretty good, but they do have some pitting on them from rust.
It still will not turn, but does move a little in either direction. We're talking maybe 2 degrees of rotation. I guess it's the bearings.

Thanks,
Chris

 

[dubs283]

Re: Upper Locked Up

now you should tear down, clean and inspect the lower - if there is water in the upper, there is water in the lower

 

[Stamey]

Re: Upper Locked Up

Yeah, I guess I'm sunk here.
Is it possible to just replace the bearings in the upper without have to "set up" the backlash in there? I'm fixing on a budget because this is Dad's boat. By way of a long story he came into possession of it and only wants to sell it. I'm trying to make sure things are right on it, but don't want to sink all the money he would get in selling into maintenance.

Thanks,
Chris

 

[dubs283]

Re: Upper Locked Up

Is it possible to just replace the bearings in the upper without have to "set up" the backlash in there?

no

anytime you replace either gearsets or bearings or both you need to set backlash

you can buy an aftermarket drive right here on iboats and still come out ahead on the sale of the boat

 

[dollarten]

Re: Upper Locked Up

The tightness is more than likely rust that has formed in the in the double tapered bearing set . If you unscrew the big brass spanner nut where the drive-shaft assy. plugs into the upper housing , you can pull the whole assy. out . . The small nut on the other side of the drive shaft has a 15/16th nut that is torqued to 85ft pounds which gives the bearing set it's pre load . If there is any rust in that bearing set it will not turn . Check the drive yoke where the seal rides and it will more than likely be rusted .This is the area where the oil could have ran out,, you will need to take care of that area in the least

 

[dubs283]

Re: Upper Locked Up

The small nut on the other side of the drive shaft has a 15/16th nut that is torqued to 85ft pounds which gives the bearing set it's pre load

the spec is actually 70 lb/ft and that is only on bearing sets that have a spacer between them

on bearing sets that don't have the spacer you need to set rolling torque using a dial inch pound torque wrench and turning the nut 1/16 turn at a time

in any case the op's bearings are shot and need to be replaced - if they go this route they will need a manual and special tools and reseal the entire drive assy (upper and lower)

at this point it would seem to be more economical for them to price out aftermarket drive assy's seeing as they are not keeping the boat

 

[Stamey]

Re: Upper Locked Up

Thank you for the useful advice. Gonna call Dad now and give him the bad news.

Thanks,
Chris