mercruiser 470 grinding

[toddw]

I have an '81 mercruiser 470, alpha leg, that makes a grinding noise when running. This noise was mostly noticeable when turning hard in either direction. It is now easily heard all the time.Several months ago I backed the boat into a stationary object while trailering with the leg up.Could I have possibly bent the drive shaft and this is causing the noise or is it likely something else? Thanks Todd

 

[Hog Wild]

Re: mercruiser 470 grinding

I really do not recommend any more running of this drive unit. I'm thinking your not doing the repair yourself, correct? Then just take it in and have the unit examined. Pretty sure something is bent and it'll be very easy to tell upon disassembly which WILL need to be done. You will probably need parts but it's hard to tell how many. But running will cause you to need MORE parts and could ruin the entire drive at many thousands in replacement. Your probably still looking at and expensive repair (1000 - 2000) but just a wild guess a shop should be able to give you a good estimate up front

 

[Don S]

Re: mercruiser 470 grinding

Sounds like u-joints have gone bad, and now it's getting worse, possibly gimbal bearing also.<br />You need to pull the drive and check the ujoints and gimbal bearing, and see if there is water in the bellows. If there is water in the bellows that is what is destroying the ujoints and gimbal. Either the bellows is bad (they should be replaced every 4 or 5 years.) or the seals and rings where the drive installs on the pivot housing are bad and needs replaced.<br />Also, water will get into the drive from the bellows leak.....Not good.

 

[Trent]

Re: mercruiser 470 grinding

I agree with Don. Noise when turning is normally the U-Joints. Time to check as was said. You have been pulling the drive every year to grease the u-joints???