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How to repair stipped lug bolt holes?

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I just discovered that my '42 Century has one and a half, okay, two stripped lug bolt holes in the front hub. Other than replacement of the hub, what other options are there to repair the threads? Has anyone used Heli-coils ? Did GM use these hubs on other makes, Cad's, Olds, etc? Does anyone have a parts interchange manual to tell me what years these hubs may be the same? I discovered this situation when I swapped out the wheels for 15" rims and Diamond back raials, now I'm afraid to drive it.

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Benefits of AACA Membership.

I would take the hub to a machine shop, and see if they can weld up the stripped holes ( most likey they do not have to shut the holes) , redrill and re-tap the threads. But before that I'd see if I could get a tap from your local tool vendor to run through the stripped holes. If you can get a straight start in the outside threads it may be possible to restore the stripped thread further in.

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Depends on the material and method of manufacture. If you are dealing with high grade cast iron, which may well be the case, it is probably wise to avoid anything that brings the metal to melting point,because you risk turning graphite carbon form to iron carbides which are brittle and hard, and can cause failure of what is a critical component. If you do have to add material, you could use nickel bronze, which will wash on at a much lower temperature, and is generally stronger than the original material. This is a brazing process with a slightly oxidizing oxy-acetylene flame, using bronze flux as wetting agent. As for your studs, you may find a wheel stud from something else which has a straight knurl below the head for locking in a plain hole, but is same diameter and thread. At best you may find a stud which will fit the damaged hole without you even needing to build up and re-drill.

Ivan Saxton

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I've used helicoils in a lot of applications and haven't had one fail yet. That is the route that I would go. Dave!

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Helicoil definitely, easy quick repair & if you dont have the expertise any good machine shop should handle it. Heat - no way !!!!!!

313

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Heli-coils are made for a ONE time application, they suck. The only thing that holds them in the hole is spring tension. They usually turn when you remove the bolt. Do not weld something like this either. You are asking for big trouble. You called this a "lug bolt". If that is what you truely mean have a stud pressed in and use a nut on the wheel, like normal cars. Or to retain the stock apperance, use a threaded insert like a Keen-sert available from McMaster Carr. Keen-serts are easy to use and use normal taps and tools. Or use a Time-Sert, you will have to google that for a dealer. Time-serts are excellant but take special tools. $$$!! Do not use a Heli-coil, you won't be happy.

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Have done some repair on cast iron when I worked on some ships in The port of Milwaukee . It is a two part Epoxy that is machinable . there might be a lot of products out there now as this was in the early 80's . did a short search and found what I think what we used . It was VERY EXPENSIVE but worked great . be sure you have the exact hole location first some how with a jig or set up on a drill press /mill so you can be sure of the location you need . Hope this gets you in the right area . Mike

http://www.belzona.com/1121.aspx

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<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: mmuehlba</div><div class="ubbcode-body"> It is a two part Epoxy that is machinable . Mike

http://www.belzona.com/1121.aspx

</div></div>You are kidding, right? Fixing a thread that holds on a wheel with epoxy? That stuff is made to fix flanges on pipes. Might as well wrap the bolt with teflon tape.You guys scare me!!

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Heli-coils are made for a ONE time application, they suck. </div></div>

I disagree,

If you do not know, you are suppose to use lock tight to lock the helicoil into place so that it will not move. The helicoil is also harder than the original treads and increasing the size of the hole to tap for the helicoil, also increases the surface area that holds the helicoil. many times it is better than the original hole. Helicoils rarely move even with out lock tight and there is no reason that you cannot take a bolt in and out of the hole numerous times. The only other alternative is to get another hub. I've installed my share in industrial machinery and many other applications and have not had one fail yet. If these will hold a drive sprockets and rollers on a bulldozer, they will hold a wheel on your car as long as they are properly installed. Dandy Dave!

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Might as well wrap the bolt with teflon tape </div></div>

Teflon tape would never work. Use duct tape.

Your suggestion of an insert seems the best of the fixes so far but it will probably require the services of a machine shop to get the new hole drilled and tapped straight.

If it were me with the problem, assuming the hub is cast steel, which I'm pretty sure it is, would be to drill the stripped hole out and tap it to 5/8-18. Then I would make a threaded bushing with a 5/8-18 O.D. and a 1/2-20 I.D.

I'd then either hard or soft solder the bushing in place. The solder will keep the bushing locked in place and the threads will provide the pull out strength. Actually there are some super duper thread locking compounds that would probably work.

Like most fixes there are a few different ways to skin this cat. Probably the easiest way, and the least expensive, to fix this problem is to just buy a new drum........Bob

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well I can not know every thing BUT .There is a lot if information at that sight but only if you have different ideas than a standard old way of thinking , also might need some newer tools for others . Mike

monkey1.JPG

REBUILDING STRIPPED HEADS

Problem: Damage to threads is a common problem which if repaired conventionally can lead to an expensive repair bill and result in odd sized bolts having to be used.

Belzona Solution: Belzona 1000 Series Metallic Polymers can provide a quick long-term solution to the problem which allows the original bolt to be used. Working procedures and product options can be obtained from your local Authorized Belzona Distributor.

http://www.belzona.com/enc.aspx

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You need to find the pile of original parts that a Street Rodder replaced with latemodel parts.

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I'll go with Dave on this. We have been using Heli-coils for years on heavy truck hubs, aluminum transmission bolt holes, and even engine blocks. If done correcting, they are permanant. Any mechanic can do the job.

Wayne

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Have the machinist drill new holes between the old holes and thread them.

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> Have the machinist drill new holes between the old holes and thread them</div></div>

Yes sir, And yet another way to skin this cat. Good thing it has 9 lives. I do beleive the voices of them that knows makes me vote for the helicoil/thread lock solution....Bob

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Mike, Nice tractor wrench, I've found that this combination US Standard and Metric wrench comes in real handy at times.

post-31159-143137983448_thumb.jpg

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Looks like Whitworth to me...........

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Helicoils are fine. We use them in aerospace applications all the time. Locktite helps, but they do sometimes back out. The alternative is a bushing style thread insert with locking tabs. One brand name is KeenSert. Once you install the insert, you tap the lock tabs down, wedging the insert into place so it can't back out. You can get them from McMaster Carr (www.mcmaster.com). Search for "thread insert".

post-48036-14313798346_thumb.gif

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<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bhigdog</div><div class="ubbcode-body">

Your suggestion of an insert seems the best of the fixes so far but it will probably require the services of a machine shop to get the new hole drilled and tapped straight.

</div></div>

Geez, doesn't anyone own drill presses anymore. This isn't science we're discussing here. It's simple 101 repair.

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Nearchoclatetown is on top of this one... Google >timesert.com< for a user friendly product that can take you back to your original size thread/bolt size. Heli-coil has usful applications but this is not one of them. For safety and repetitive use applications its "timesert"

Mike I really like two part Epoxy products but for this job... maybe not a good thing. hows the REO ?

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Geez, doesn't anyone own drill presses anymore. This isn't science we're discussing here. It's simple 101 repair. </div></div>

I agree. I'm certainly not critizing the original poster but you would be surprised what tools and capabilities folks don't have. In this case the the tap drill required for the insert is 45/64 tapped out to 3/4/-16. That's pretty hefty for the average hobbiest who usually might have a 1/2 horse press turning a 1/2" chuck. Same for the helicoil tools taps and inserts.

A lot of guys are maintaining their cars with hand tools and maybe a pistol drill. Nothing wrong with that but in that case this repair is beyond their capabilities. That's why I said the best repair might be to just find a replacement or have a shop do it.........Bob

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Well stated Bob! My guess is that a NOS hub would equal the parts and machine shop cost.

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I agree. I'm certainly not critizing the original poster but you would be surprised what tools and capabilities folks don't have. In this case the the tap drill required for the insert is 45/64 tapped out to 3/4/-16.

Buick have 3/4 inch lugs!?!?! I kinda doubt it.

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Buick have 3/4 inch lugs!?!?! I kinda doubt it. </div></div>

You doubt correctly. They are 1/2-20. But the INSERT for a 1/2-20 requires a 3/4-16 tapped hole...........Bob

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I have an interchange manual but it lists the cars by model numbers not names. I'm not familiar with a 42 Century, what model is that (40, 50, etc.) Also need to know front of rear.

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