Zinc Removal

[JSMoore]

I was removing the zincs on my outdrive in preparation for some zinc chromate primer and a paint job. During the process, one of the bolts snapped off. Now, I can't get the zinc out of the drive.

The zinc involved here, is #37 in the illustration below. The bolt that snapped off is #36. The problem is that the bolt snapped off inside the zinc. So, there's still about 1/4 to 3/8" of the bolt inside the zinc. There's no way I can slide the zinc to the side and out of the drive housing.

I don't mind destroying the zinc. That can easily be replaced. I just don't want to damage the drive housing. And, once the zinc is out, I'll have to get the broken off bolt out of the drive housing.

Any ideas how I can get that thing out of there?
Thanks!
JSM

 

[Bluestream]

Re: Zinc Removal

You are going to have to drill them out. It will be difficult as they are small bolts surrounded by soft aluminum and your bit may want to slide off the bolt into the aluminium. . You might try an easy-out if the bolts are big enough to drill into.

No magic bullet that I know of...

 

[dsiekman]

Re: Zinc Removal

If going after the bolt doesn't work, I would try to remove as much of the zinc as possible by drilling and using a dremel with a cut off wheel. Just be really careful and go slowly. You probably want a mask or resperator of some type while cutting as well. Actually, a fein multimaster would probably work really well, but they're pretty salty. I've the dremel equivalent but I'm not sure if it is as good.

 

[dockwrecker]

Re: Zinc Removal

" Actually, a fein multimaster would probably work really well, but they're pretty salty. I've the dremel equivalent but I'm not sure if it is as good."

I'm really working hard on myself to find an excuse to buy the Fein
Tool lust is my vice...

 

[PiratePast40]

Re: Zinc Removal

Santa brought me the Dremel version last Christmas. Works pretty good but doesn't do straight lines very well - or maybe it's that I can't cut in a straight line

 

[Bluestream]

Re: Zinc Removal

An air powered cut off tool may work better. Cut 90% through then split it with a screwdriver.

 

[JSMoore]

Re: Zinc Removal

Thanks, guys. I do have a dremel tool with fiber cut off wheels. I was pretty sure I was going to have to cut the zinc and split it to get to the bolt stub inside. I'm just not quite sure how to get the that broken off bolt out. I guess I'll try lots of penetrating oil and some needle nose vice grips.
Thanks Again!
JSM

 

[veritas honus]

Re: Zinc Removal

Thanks, guys. I do have a dremel tool with fiber cut off wheels. I was pretty sure I was going to have to cut the zinc and split it to get to the bolt stub inside. I'm just not quite sure how to get the that broken off bolt out. I guess I'll try lots of penetrating oil and some needle nose vice grips.
Thanks Again!
JSM

Use an Easy-out. Napa has them. You'll be amazed how easily you can remove a broken bolt. If you're not familiar, it looks like a short stubby drill bit with reverse, knurled threads and a square top. You drill a hole into the top of the bolt and then screw the Easy-out into it. Put an open end wrench onto the square top and as you tighten it, since the knurled threads are reverse, once they snug up and bite into the inner metal of the bolt, the bolt unscrews as you turn. You can use a drill instead of a wrench, but use it low speed. Go slowly. If you go too fast, the knurled threads can strip out the inside of the bolt. If this happens, it's still OK. Simply use the next size larger Easy-out and be more careful. They cost about the same as good quality drill bits. Napa has them single, sets of four, and larger sets. They're an excellent tool to have on hand. Good luck.

Safe and happy boating always!!!

 

[StevNimrod]

Re: Zinc Removal

If you really wanted to get creative you could speed up electrolysis and let the zinc sacrifice itself how it normally would (but faster). Would take a bit of doing though.

I've had mixed experience with Easy Outs. Half the time they've worked, the other half the time they've snapped off in the bolt. Not fun to mess with at that point.

You might have success with the Dremel and not miss the mark if you cut what you can see and slowly grind away at the rest. There's a local welder who is good at finding creative ways to remove stubborn fasteners and I've found in dealing with him that a little heat does wonders. I like doing most things myself, but have found that "quitting while you're ahead is not the same as quitting".

 

[JSMoore]

Re: Zinc Removal

Use an Easy-out. Napa has them. You'll be amazed how easily you can remove a broken bolt. If you're not familiar, it looks like a short stubby drill bit with reverse, knurled threads and a square top.

I am, in fact, VERY familiar with easy-outs. The problem with this particular fastener is how to get an easy-out on it. The bolt is a small one, and, it is quite deep, up inside a pocket that is possibly deeper than the easy-out is long. So, I'm trying to come up with some other way of doing it without "reinventing the wheel".

 

[erie_guy]

Re: Zinc Removal

JSM,

The cut away looks like a VP-SX drive. Is it? My SX drives had a second anode on the lower drive leg inside the exhaust housing. Believe it was called out as a Pencil anode. This anode was almost gone and when I attempted to get a replacement, I learned the anode was no longer available and not needed on the drive. Apparently the horseshoe-shaped anode on the nose of the drive protects it adaquately.

You might check with your local marine dealer to determine if the anode you are trying to replace is still recommended by VP.

 

[veritas honus]

Re: Zinc Removal

I am, in fact, VERY familiar with easy-outs. The problem with this particular fastener is how to get an easy-out on it. The bolt is a small one, and, it is quite deep, up inside a pocket that is possibly deeper than the easy-out is long. So, I'm trying to come up with some other way of doing it without "reinventing the wheel".

Is a ratchet extension out of the question? (...to extend the Easy-Out) I don't know how much room you have to work with. I'd imagine, though, if you have enough room for a drill, then there's enough working space. If a ratchet extension is too big, maybe a screwdriver extension from a multiple driver bit set. I think I may be grasping at straws here; but I hope this helps:redface:.

 

[twkjr 1250]

Re: Zinc Removal

i have ground the remainder of the screw shaft into the shape of a smaller nut shaped end and used a smaller size socket . try heating it up also

 

[JSMoore]

Re: Zinc Removal

JSM,

The cut away looks like a VP-SX drive. Is it?

You might check with your local marine dealer to determine if the anode you are trying to replace is still recommended by VP.

Sorry, I forgot to say that it's a OMC Cobra, behind a 4.3L V6 and pushes a 3500lb. 1987 Mark Twain MTC-215, 21 foot cuddy.

I've gotten some good ideas. So, thanks to those that have offered guidance! It DOES help.
Cheers!
JSM