Stripped hole in midesection, and broken casting under pump wear plate

[RKwood]

I dropped the lwr unit on one of my 1.6l Sea Drives and found one of the attaching bolt holes partially stripped in the mid-section.<br /><br />Threads are washed out for the first 1/4" or so. <br />I am unable to restart bolt in the hole, what should I do to repair?<br /><br />Also upon removal of water pump found a part of the aluminum housing broken away under pump wear plate. Break is between tapped holes on the side of the housing. The wall in casting is thin there, probably got broken when someone tried to pry off impeller. Found a chunk of epoxy to fill where chunk was missing, it seemed to hold up but lakced "robustness".<br /><br />I thought a bit of JB Weld would do nicely to replace small missing chunk, but have never worked with stuff so looking for some tips.<br /><br />RKwood

 

[Hooty]

Re: Stripped hole in midesection, and broken casting under pump wear plate

If there's enough meat around the stripped hole in the midsection you can drill it and put a heli-coil in it. <br />The chunk missing from around the w/p is an ideal place for JB Weld. Clean it up good with a rough file or course emory paper so the stuff will have something to get ahold of and put ah big ole glob on it. It's good caca.<br /><br />c/6<br /><br />Hooty

 

[Tinkerer]

Re: Stripped hole in midesection, and broken casting under pump wear plate

What Hooty said.<br /><br />Alternatives are Loctite make a thread repair kit (epoxy) but I've never used it, or drill out hole so no thread and re-tap it to next size up bolt, if there's room. <br /><br />Problem with Helicoils and the like is that you've got to buy fairly expensive tools to use them and you'll likely never use them again. They're expensive here in Australia anyway, like about $50 to insert one Helicoil versus about $10 for JB cold weld.

 

[Hooty]

Re: Stripped hole in midesection, and broken casting under pump wear plate

Here, I think the tool is like $20-25. You could take it to a machine shop.<br /><br />c/6<br /><br />Hooty

 

[jim dozier]

Re: Stripped hole in midesection, and broken casting under pump wear plate

I vote for a helicoil for the stripped bolt. They are easy to install. Yes the kits usually run about $35-$50 (NAPA Auto parts and others) here in the states depending on the size of the bolt but you'll probably need them in the future and they come with a bunch of coils.<br /><br />Since the lower unit is already removed I vote you take it to a good heli-arc welder and have it welded up. Then you can have the hole redrilled and tapped. Then you won't have to worry about it in the future.

 

[bhalsdorf]

Re: Stripped hole in midesection, and broken casting under pump wear plate

In a pinch I have just ground the bottom of a bolt to leave a tang to grab the heli-coil and inserted it that way. It does work in the absence of having a tool.

 

[oldboat1]

Re: Stripped hole in midesection, and broken casting under pump wear plate

had a similar problem last year, and filled the area with West System epoxy mixed with powdered aluminum filler. It worked fine for repairing the damaged area as well as reseating the bolt. To reseat the bolt, I wrapped a bolt in plastic wrap and screwed it into the existing hole, then filled around it with epoxy. The plastic wrap keeps the epoxy from sticking to the bolt.<br /><br />If you do something similar, be sure to sand the surface under the wear plate perfectly flat so the fit is airtight.

 

[Hooty]

Re: Stripped hole in midesection, and broken casting under pump wear plate

oldboat1, that's excelent advise. Another way that works real well is clean the bolt real good and wax it with Meguiers Mirror Glaze Paste Wax. That's the wax fiberglass boat builders us as a release agent to get boats out of the molds. Give it four or five good, healthy coats wiping of the previous coat before applying the next.<br /><br />I still recommend JB Weld.<br /><br />c/6<br /><br />Hooty

 

[RKwood]

Re: Stripped hole in midesection, and broken casting under pump wear plate

Thanks to all for the good info!<br /><br />To clarify the stripped hole stuff....<br /><br />The hole in question is in the lower part of the mid-section where the lower unit interfaces. It looks like the first 1/4" or so of the initial threads is shot, I still have probably about a good inch and a half of good threads. If the initial "wash out" of the threads wasn't there I still have plenty left for retention of the bolt.<br /><br />A few folks at work suggested a "thread chaser", which was described as a less agressive tap. I have heard of them, but never used or seen them. Does anyone have any expierence (and or tips for use) with these?<br /><br />My obvious fear is cross threading which would force me into one of the other methods posted here!

 

[Tinkerer]

Re: Stripped hole in midesection, and broken casting under pump wear plate

Are you sure you've got right size bolt for the thread? The wrong size will often go in part way before binding and will then strip if forced in. I've got a motor sitting in my workshop with exactly the problem you have because some idiot (not me!) forced a metric bolt into a whitworth thread.<br /><br />Sounds like either your bolt or the start of the good thread is closed so that it can't get a start. Check the bolt tip and file out the start to a clean sharp point and see if it can start in the thread. Also clean out the thread with penetrating oil and toothbrush or whatever fits (mascara brushes are tiny and wives never miss one or two) as mighthave metal filings blocking thread . If that doesn't work the thread in the hole is compressed or damaged and you'll need to clean it with a suitable tap.

 

[ob]

Re: Stripped hole in midesection, and broken casting under pump wear plate

RKWood,No problem with using a regular set of taps.Get a full three piece set and clean out what you have.Use a toothpick or similar tool and depth measure the hole in question.Chances are ,the original bolt never reached the bottom of the hole and you can probably use a slightly longer one on reassembly.Just be sure that the last tap that you run in the hole is a bottom tap that will insure the threads are cut to the bottom of the hole.And always use the taps in a two direction method as to allow them to expell the shavings and not cause galling.Good luck.

 

[RKwood]

Re: Stripped hole in midesection, and broken casting under pump wear plate

I now have a set of taps which match the current threads I have, but I am not quit sure on how to properly use them. I think I'm clear on the bottom tap, but which of the other two do I start with?<br />Also, what do you typically use to turn the taps?<br /><br />Needless say this will be my first time, a tap virgin if you will!<br /><br />I would appreciate some additional guidance. I'm really fearful of really "screwing" up the hole.<br /><br />As always thanks for the help.

 

[ob]

Re: Stripped hole in midesection, and broken casting under pump wear plate

RK,The starter tap is the one that is most tapered.The medium tap is the one that is slightly tapered ,and the bottom tap is the one that cuts threads to the hole bottom and is only tapered on the first thread to assist starting in hole.Depending on how much of the threads are wiped in the hole you are tapping will dictate whether you start with the starter tap or the medium tap.It is best to use a tap handle to perform this task.They are designed to hold the square shank of the tap while you use the T handle to run tap in and out while cutting threads.Some of these tap handles have a ratcheting feature that makes the task a bit easier.You can use a wrench on the shank of the taps ,but need to be cautious to choke down grip it as to keep the torque motion closest to the tap shank and not out to the side too far that it will cause the tap to be forced crooked.<br /><br />Run the first tap into the hole after starting squarely until it bottoms in hole making sure that you back it off ocassionally to clear the filings.Then do the same thing with the bottom tap and you're finished.Best to use some lubricant on the hole while tapping.They make a tapping fluid for this but light oil works well too,since you'll be cleaning out a previously threaded hole .Good luck.

 

[RKwood]

Re: Stripped hole in midesection, and broken casting under pump wear plate

I picked up the tap handle today. I hope to give it a try this weekend, but may be stuck working. <br /><br />Thanks to all for the tips!!!! <br /><br />I'll let everyone know how things work out.