Stern drive allen-head screw

[jimrockireland]

Anyone have a secret way of removing a rusted on 3/8" allen-head set screw above the trim tab on the stern drive? I've soaked it in WD40 and thought I would ask around before I threw caution to the wind and put as much force as possible on the wrench. The stern drive is on a 1983 Mercruiser 305/5L MCM228 engine.

 

[Bondo]

Re: Stern drive allen-head screw

Anyone have a secret way of removing a rusted on 3/8" allen-head set screw above the trim tab on the stern drive? I've soaked it in WD40 and thought I would ask around before I threw caution to the wind and put as much force as possible on the wrench. The stern drive is on a 1983 Mercruiser 305/5L MCM228 engine.

Ayuh,... Melt away the zinc tab with a propane touch,...

It's meltin' temp is lower than the drive's housin',...

 

[Eric 3.7LX Alpha 1]

Re: Stern drive allen-head screw

Ayuh,... Melt away the zinc tab with a propane touch,...

It's meltin' temp is lower than the drive's housin',...

X 2 what he said.....

I had to do the same thing last time on mine... I even took a video of it. Never uploaded it but I can. The video is just over 20 minutes long and boring as heck. Keep the flame in one spot, don't move it around, with propane it takes a while to get the zinc hot enough to melt. AND don't breathe in the gas from the melted zinc .... not good for you .... and Don't let the splatter bounce and hit you, it's also not good for you. lol

The drive had zero damage from the torch. Was discolored but was just some smoke that easily washed off.

 

[oldjeep]

Re: Stern drive allen-head screw

The one that holds the trim tab on? If so then why not hit it with the impact wrench, worst case you break it off.

 

[tpenfield]

Re: Stern drive allen-head screw

Hopefully the zinc will expand enough to give the stainless bolt up before it melts . . . but if it does not, then melting it will do.

Be safe with the torch.

 

[jimrockireland]

Re: Stern drive allen-head screw

Is there any downside from applying force to the screw and possibly breaking it off before going to the zinc melting procedure?

 

[Eric 3.7LX Alpha 1]

Re: Stern drive allen-head screw

The bolt head will eventually strip... at least that's what mine have done.

Here's the video I took while melting mine off:
http://www.youtube.com/watch?v=ZfdEXcFp5Tc

 

[Bondo]

Re: Stern drive allen-head screw

Is there any downside from applying force to the screw and possibly breaking it off before going to the zinc melting procedure?

Nope,... yer more likely to strip out the head,... Bust away,...

 

[jimrockireland]

Re: Stern drive allen-head screw

Thanks for the help. I soaked it in WD40 for 5 hours and put a big pipe on my wrench. It came out nicely.

 

[gregk101]

Re: Stern drive allen-head screw

Does anyone know if the allen head bolt that holds the zinc plate on can be removed/replaced? The allen head on mine was stripped, I used a grinder to remove the zinc plate as others have mentioned, however the bolt was ruined while doing that, and now I cannot get it to push up and out. tried screw extractor with no luck. thanks in advance.

 

[Fun Times]

Re: Stern drive allen-head screw

Does anyone know if the allen head bolt that holds the zinc plate on can be removed/replaced? The allen head on mine was stripped, I used a grinder to remove the zinc plate as others have mentioned, however the bolt was ruined while doing that, and now I cannot get it to push up and out. tried screw extractor with no luck. thanks in advance.

Hi there gregk101, welcome to iboats! I know it was easier for you to tag your question onto the end of this old thread since your question pertains to most of the conversation referenced above but unfortunately it may not make it easier for our helpful members that like to log on from time to time and answer a few quick questions before moving on to something else in their life. They may not notice the original posters date and answer the first question at the top before reading all the others then they come to find out that the OP has already been helped and long gone in turn skipping your question altogether. So it's always best to start a new thread of your own. For future reference, Please see our announcement linked right here, Announcements - Mercruiser I/O & Inboard Engines & Outdrives

Now for your question, yes the zinc plate Allen-head screw will come out but first you have to separate the upper drive housing from the lower gear housing. And be sure to put the new bolt in before installing the two half's. See 3B-53 http://www.google.com/url?sa=t&rct=...Yg9kSPo392g9RDfEcOIAGbw&bvm=bv.62922401,d.cGU

You may have to lube and tap on it if it is stuck with corrosion. PB blaster may work best. Also that bolt is coated with red Loctite so it can be tough to remove at times. Heat may help as well. A new screw from Merc is part number 10-32470 SCREW, (.437-14 x 1.75) if one don't come with a new zinc. Hope this helps, Good luck.