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Screw/bolt head broke off - HELP
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Author:  Winedown [ Sun Apr 03, 2011 5:28 pm ]
Post subject:  Screw/bolt head broke off - HELP
Murphy struck hard today after an afternoon of boat preventive maintenance. 16 spark plugs changed out. 1 impeller changed out. 1 impeller on the counter because one of the screws/bolts/whatever you want to call it that holds the impeller housing to the water pump snapped as I was putting everything back together. After inspecting the head of it that was still in my socket it looked to be pretty corroded...which would make sense seeing as how I barely had any pressure on it when it the head snapped off. Any ideas on how to get the screw out of there? There's about 1/4 inch of thread sticking on that I may be able to grab and twist, but other than that I'm not sure what to do short of drilling it out.
Author:  firecadet613 [ Sun Apr 03, 2011 5:35 pm ]
Post subject:  Re: Screw/bolt head broke off - HELP
Get a pair of vice grips on it and SLOWLY try to back it out. Thats the easiest way to do it.
Author:  Cap'n Morgan [ Sun Apr 03, 2011 5:59 pm ]
Post subject:  Re: Screw/bolt head broke off - HELP
The Vise Grips are the easiest way, IF you don't damage what's left of the bolt , and if there is enough to grab onto in the first place. You may get lucky, but remember, it is already corroded and likely not easy to back out. Spray it with Liquid Wrench or WD-40 and let it sit overnite before you try it.

2nd method is if you have a dremel tool, cut a line in the head of the bolt, and see if you can get a screwdriver on it and back it out.

Otherwise, the cleanest method is to just use an easy-out.
Author:  Winedown [ Sun Apr 03, 2011 6:40 pm ]
Post subject:  Re: Screw/bolt head broke off - HELP
I like the dremel idea...that may work. Thought about the vice grips but I'm afraid I may just end up snapping it again and making things worse.
Author:  Cap'n Morgan [ Sun Apr 03, 2011 7:20 pm ]
Post subject:  Re: Screw/bolt head broke off - HELP
An Easy Out has the highest probability of success.
Author:  Rader [ Sun Apr 03, 2011 7:47 pm ]
Post subject:  Re: Screw/bolt head broke off - HELP
Try some PB Blaster and let it soak overnight. I usually don't buy in to those kind of products but that stuff works great. Saved me more than once! A vise grips should back it right out after a good soaking. Good luck. Been there done that!
Author:  jvthundercat [ Mon Apr 04, 2011 8:54 am ]
Post subject:  Re: Screw/bolt head broke off - HELP
Be as careful as possible, but if you don't have any success, for 20 to 50 bucks, you can just go a most machine shops and they will drill it out and chase the threads. Even if you screw it all up, they can put in a stainless helicoil and you have new threads. This would be a good time to get some anti-seize to put on your thread from now on.

The easiest and cheapest thing to do right now is get a left hand drill bit. Pin punch it in the center and start slowly drilling.
If it does not come out with that, you have a clean hole to put in an easy out. If that does not work, or god forbid you snap that off in there, take it to a machine shop and let them do it. Some mechanical shops could do it, but choose wisely.
Author:  jvthundercat [ Mon Apr 04, 2011 8:56 am ]
Post subject:  Re: Screw/bolt head broke off - HELP
Another thing, WD-40 does not remove corrosion, it displaces water to prevent corrosion. Get something that will actually eat through it.
Author:  Graham R [ Mon Apr 04, 2011 9:26 am ]
Post subject:  Re: Screw/bolt head broke off - HELP
If it was the correct length bolt, which I'm sure it was, I don't think they should "bottom out" in the tapped holes in the backplate. If that is the case, there should be no stress on the threads, so the stub should screw out quite easily with "vise grips etc".

One of the originals on mine (painted over in a thick layer of red paint) was a real pain to get out as I couldn't get a socket over it far enough or a screwdriver into it's head; access was quite limited. I had to grind the head off with a Dremel, the remaining stub came out very easily. I replaced mine with stainless "Allen" cap head bolts/ washers; much easier to remove/ refit as unless you're very unlucky, the bolt will stay on the driver instead of falling into the bilge and disappearing. Nickel "antiseize" compound seems to keep corrosion of the threads at bay.

Graham
Author:  scottmph [ Mon Apr 04, 2011 1:48 pm ]
Post subject:  Re: Screw/bolt head broke off - HELP
Cap'n Morgan wrote:
An Easy Out has the highest probability of success.


plus 1 on this method
Author:  Graham R [ Mon Apr 04, 2011 4:19 pm ]
Post subject:  Re: Screw/bolt head broke off - HELP
Those bolt threads are less than 5 mm in diameter. Access to them, low down at the front of the engine is normally not wonderful, I'd be surprised if there's enough room ahead of them to get a drill in there, I wouldn't fancy my chanches of drilling into one to make a hole for the screw extractor to screw into unless the pump was removed from the engine; you may as well try vice grips first !

Graham
Author:  Winedown [ Mon Apr 04, 2011 10:00 pm ]
Post subject:  Re: Screw/bolt head broke off - HELP
Graham R wrote:
Those bolt threads are less than 5 mm in diameter. Access to them, low down at the front of the engine is normally not wonderful, I'd be surprised if there's enough room ahead of them to get a drill in there, I wouldn't fancy my chanches of drilling into one to make a hole for the screw extractor to screw into unless the pump was removed from the engine; you may as well try vice grips first !

Graham


Agreed. After learning more about the easy out, I would have to pull the entire water pump to try this method. I'd have to hang upside down and try to center the drill on the screw for that method to work unless I pulled the pump entirely. That will be the last resort. Going to attempt the PB Blaster and vice grips method...with any luck I'll be able to get down there tomorrow after work. Otherwise it may have to wait until the weekend.
Author:  wkearney99 [ Tue Apr 05, 2011 4:43 pm ]
Post subject:  Re: Screw/bolt head broke off - HELP
A right angle drill might make getting to the bolt less of a hassle. Best tool I've ever bought was my Dewalt cordless right angle drill.

I second the PB method. Apply some PB then tap the bolt and reapply the PB. This helps loosen the surfaces a bit and that lets the oil penetrate a little more. Sometimes it's a matter of apply, tap, wait a day, repeat... for a few days.

There are also some grooved socket-like gizmos designed to grab onto the outside of a broken shaft or rounded bolt head. Sort of the opposite of an easy-out drill bit. The threads inside the socket bite into the material as you crank it in a counter-clockwise loosening direction. I've had to use some for 1/2 and 9/16 socket heads, but never for just the remaining nub of a broken bolt. Can't recall what they're named though.

If you don't already have a really good set of genuine Vise-Grips now might be the time to make the investment. I've found that some of the cheaper imitations don't do anywhere near as good a job.
Author:  Winedown [ Tue Apr 05, 2011 7:08 pm ]
Post subject:  Re: Screw/bolt head broke off - HELP
Success!! PB Blaster and vice grips. Now I just need to find a replacement bolt (actually I'll replace all 4). I'll give the local Chap dealer a call tomorrow and see if they have any laying around the shop.
Author:  aguyindallas [ Tue Apr 05, 2011 10:42 pm ]
Post subject:  Re: Screw/bolt head broke off - HELP
That's great news!
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