View Full Version : Alternator Question
cst573
06-16-2007, 05:39 PM
I had my alternator seize up this morning and break the shaft that goes into the alternator as I was going down the lake. Anybody ever had this happen? Does anyone know why this happens? (I am assuming that the shaft bearing caused this seizure) I have not tried to take it apart. Is it worth having rebuilt?
Had to call a friend and get a tow back to the dock. That sucked!
Luckily I was able to call my local Mastercraft dealer and they had a new one in stock. I picked it up and will replace it in the morning.
Excessive current draw from a variety of sources, sand working its way in, belt too tight, condensation from a cover that seals and doesn't breathe, high temperatures causing the sealed bearings to leak are all possible. Hard to tell from here but a thorough inspection should show something.
What kind of engineering?
cst573
06-16-2007, 06:12 PM
It was the factory alt. and I assume it was the original one. (year 2000)
Its a 51 amp alt.
I do have one amp in the boat but the radio was not on at the time of failure. Only have the factory accessories on the main battery.
My cover is a Mastercraft cover and has vents.
I don't think the belt was to tight, I remember it having a little play in it.
Would I have seen any fluid coming out if the sealed bearing leaked or would it stay inside the alt. housing?
You probably wouldn't see any lube- the shaft or assembly would probably sling it around the inside of the housing and it would dissipate before it came out, and there's not that much of it. I would call MC and ask about this one. I have never heard of a shaft breaking this way. If a pulley is out or round, a shaft is bent or there's some other cause of oscillation, the one that meets the resonant frequency will be first to go.
uncleboo
06-17-2007, 12:14 AM
I would bet that it was torqued too tight. You could still have play in the belt even after someone torqued it down too much. That could put too much bind on the bearing and lead to the breakage you experienced.
cst573
06-17-2007, 10:01 AM
Got the alternator and I am in the process of replacing it. There is a key way in the shaft (to hold the cooling fin and pulley I assume) but my pulley has no slot for the key way. Has anyone seen this? How do I go about getting the pulley back onto the shaft of the new alternator?