lower unit to upper unit bolts

[challenger]

Hi I have a 1995 maxum with a 4.3 liter alpha one drive. I have taken the lower unit off to replace the seawater pump. Underneathe the large round anode at the back of the unit is a bolt that goes from the bottom half and threads into the upper half holding the cas together. The bolt broke while taking apart. I have since drilled out the bolt and will retap the hole. Does anyone know what the bolts are made of?(steel,hardened steel, aluminum, zinc coated) I dont believe it was stainless or I wouldnt have snapped the bolt. And I believe stainless gets corrosive if under water for long. Also the four bolts that bolt the lower half to the upper half(two on each side), three of the nuts have hairline cracks in them. What kind of nuts can I get to replace them? Thanks Shawn

 

[Haut Medoc]

Re: lower unit to upper unit bolts

Get them from a Mercruiser dealer....<br />Pretty sure they are stainless .....JK

 

[crazy charlie]

Re: lower unit to upper unit bolts

The Lock nuts are stainless.They are an odd thread so you may not be able to get them at a hardware store.I have had the bolts off many times and assume they are also stainless.As HM states,you can get em at a dealer.West marine can order them for you but I am certain they dont carry them in inventory.

 

[Don S]

Re: lower unit to upper unit bolts

The bolt is a 3/8-16 X 1" Stainless bolt.<br />The nuts are a flange nut, also stainless and is a 7/16-20 thread. The flange on the nut spreads the load better on the aluminum housing than a thin washer will.

 

[fendersfender]

Re: lower unit to upper unit bolts

I dont believe it was stainless or I wouldnt have snapped the bolt.........many people dont realize that stainless is softer than any common bolt, also referred to as carbon steel.....stainless is just plain ole carbon steel with the addition of nickel.......nickel is what gives stainless steel its anti-corrisive properties, but also makes it softer than regular grade bolts....common misconception is that stainless is harder than other bolts, when it is actually quite soft........and good quality stainless is less magnetic than poorer quality stainless due to the amount of nickel used....just a note from a steelworker