After I finished changing my oil I was putting back on the skid plate and snapped one of the lower bolts (it had rusted pretty bad). Not having a screw extractor I drilled it out and thought I got most of it. When I tried one of the other bolts it would not go in so I tried to tap it with a tap set I bought at AutoZone and that broke off in the hole! :mad:

It started to get dark so I put in the 3 working bolts for now and went to Sears to see if I could get a better tap and die set but they ranged from $50 to $200 :eek:

Any advice on how I should handle this situation? Should I just go to a mechanic to have him do this for me? I have not successfully tapped a bolt hole before but that could be cause this tap set I had was a big POS.

Thanks..

a few of things to try:
1. can you get vise grips on the tap where it comes out the back side? - I doubt it because that frame member is thick but maybe your tap is long enough?
2. if you have a welder or a friend with one - tack weld a piece of scrap to the tap - this would never work with a good quality case hardened tap - but as you said your tap broke easily so maybe cheaper material
3. a drill extractor - it is basically a reverse pitched drill bit with teeth that winds in, then once the teeth hit drives the bolt out. Again, would not work with a case hardened tap, but might work on yours
Good luck

edit - thinking about it a little more - if that tap is cheap material, a good quality titanium drill bit may get into it. Dunno, I'd try it.

Oh, I forgot to mention I was able to get the tap out. My main issue now is that when I put a bolt in there it will not catch and is rounding the threads.

Thanks for you help!

oh well that is better, I was afraid it could really suck to have a case hardened tap stuck in there. So now best to do would be to tap it out clean, but I guess you want to finish without replacing the broken tap. Here's one trick - wind the bolt from the backside - I cant get up under mine right now without putting on my ramps to see for sure but if my memory is right you should be able to do that. If you can, the bolt will have a chance to start in clean threads before hitting the mangled ones. Wind it all the way down, then take it out and put it in from bottom - should start after that. Use lots of penetrating oil, WD40 or some such lub.

If all else fails - go one size up - drill out, use your next biggest tap that is not busted, and replace with a bigger bolt.

Thanks CndInAz - I'm not sure if I can actually get to the top becase I think there is all kinds of engine in the way, but that is a great idea. If I have to go the tap route, is there a brand you would recommend? I would have spent the money on the set at Sears but I have found that their tools are just rebranded from somone else and not the best quality (this is after having bought a bunch of Craftsman stuff.)

Craftsman has gone downhill in a mjor way. If it were me, I'd just leave it as is until I could make it down to an Offroad shop to see what ideas they have for attaching it a different way. I drove around for a few months with a skid bolt missing. These skids are a constant problem always stripping out and I would think there are better ways of attaching them that they might have some ideas for.

Just like CdnInAz said use lots of peitrating oil or cutting fluid and be real slow and gentle.If you force it even the best taps will break. I have a handfull of Snap-on and other taps that are broken to prove it. If it starts to bind back it off a few rounds and work it slow and you should be good. It takes practice like anthing else.

just use 3 bolts

just use 3 bolts

I had thought about this, but the area where it is supposed to be bolted will vibrate and it will cause a metal to metal clank when I hit a bump. I jammed a piece of cardboard in there to prevent it but more importantly I'm just too anal to leave this alone ;)

Craftsman has gone downhill in a mjor way. If it were me, I'd just leave it as is until I could make it down to an Offroad shop to see what ideas they have for attaching it a different way. I drove around for a few months with a skid bolt missing. These skids are a constant problem always stripping out and I would think there are better ways of attaching them that they might have some ideas for.

I used to get all Craftsman stuff but now I'm starting to see it is junk. I like how you can get free replacements but I would rather have tools that hold up better.

I'm not sure how else this would be attached? The upper bolts are fine (as they do not see water) but the lower bolts are both rusted. If / when I get this fixed I will see if I can get stainless steel or just keep them well lubed. I don't know if we have off-road shops in Long Island :confused:

Just like CdnInAz said use lots of peitrating oil or cutting fluid and be real slow and gentle.If you force it even the best taps will break. I have a handfull of Snap-on and other taps that are broken to prove it. If it starts to bind back it off a few rounds and work it slow and you should be good. It takes practice like anthing else.


Do you have to start with a smaller tap and work your way up? The tool I had had a hand turn that would just spin at the slightest resistance so that's when I put it in my drill. It would not move otherwise.

I wasn't aware you had to use lube - thanks for that. Instead of snapping something else I wonder how much a mechanic would charge for this?


Thanks for all the replies!

I haven't looked at where the skid plate mounts, but is there a way to get a washer and locknut behind it and bolt it down that way?

where do you live, I have a Snap-on Tap and Die you can borrow.

where do you live, I have a Snap-on Tap and Die you can borrow.

I'm in Long Island / NY. Thanks for the offer! But I think I'm a little far from you.

I haven't looked at where the skid plate mounts, but is there a way to get a washer and locknut behind it and bolt it down that way?

The back was not easy to get, but I really want to fix this properly as I have to take the skid plate off every time I change the oil.

Do you have to start with a smaller tap and work your way up? The tool I had had a hand turn that would just spin at the slightest resistance so that's when I put it in my drill. It would not move otherwise.

I wasn't aware you had to use lube - thanks for that. Instead of snapping something else I wonder how much a mechanic would charge for this?


Thanks for all the replies![/QUOTE]

No, I just use the right size tap. If it is one of the ones directly under the engine with a 10mm head it takes a 6mm x 1.o tap. Never use a drill on something that small, you need to do it by hand, with a t-handle where you can feel what you are doing.

I tap holes all the time and if you use a tapered tap and just go until resistance is met and back out a half a turn and go again and keep the tap wet with oil and do NOT put any sideways force or bind the tap in anyway you should have no trouble at all. Just chasing a bad thread in a previously threaded hole should be a piece of cake.
Taps are VERY hard and VERY brittle and you were very fortunate to get the broken one out as they are MUCH harder than any drill bit, even carbide ones. I have had luck in extreme cases to freeze broken taps with liquid nitrogen and shatter them with a hammer and punch, then pick out the pieces. Even if one tiny bit of broken tap is left in there it will destroy drill bits and taps.

I tap holes all the time and if you use a tapered tap and just go until resistance is met and back out a half a turn and go again and keep the tap wet with oil and do NOT put any sideways force or bind the tap in anyway you should have no trouble at all. Just chasing a bad thread in a previously threaded hole should be a piece of cake.
Taps are VERY hard and VERY brittle and you were very fortunate to get the broken one out as they are MUCH harder than any drill bit, even carbide ones. I have had luck in extreme cases to freeze broken taps with liquid nitrogen and shatter them with a hammer and punch, then pick out the pieces. Even if one tiny bit of broken tap is left in there it will destroy drill bits and taps.

I think the problem is when I drilled it there were pieces of the old bolt stuck on the threads. Also, I can't say that I was using the right one (it was a 6 x ?). So will the tap cut out the old bolt that is stuck in the threads?

Instead of causing myself more pain, I wonder if I should just have this done by a mechnic who does it all the time?

Do you have to start with a smaller tap and work your way up? The tool I had had a hand turn that would just spin at the slightest resistance so that's when I put it in my drill. It would not move otherwise.

I wasn't aware you had to use lube - thanks for that. Instead of snapping something else I wonder how much a mechanic would charge for this?


Thanks for all the replies!

No, I just use the right size tap. If it is one of the ones directly under the engine with a 10mm head it takes a 6mm x 1.o tap. Never use a drill on something that small, you need to do it by hand, with a t-handle where you can feel what you are doing.[/QUOTE]

I'm thinking my tap was 6mm x 1.25. I have to double check.

I think the problem is when I drilled it there were pieces of the old bolt stuck on the threads. Also, I can't say that I was using the right one (it was a 6 x ?). So will the tap cut out the old bolt that is stuck in the threads?

Instead of causing myself more pain, I wonder if I should just have this done by a mechnic who does it all the time?


For the bolt/thread question, yes the tap should be able to cut the pieces of the old bolt out as the bolt is comparatively soft to the tap but this won't work as well if the parent material is aluminum, the tap could just push(bury) the steel bits into the softer aluminum. One word of warning - if you break a steel bolt off in aluminum it is imperative that you drill DEAD center and straight. If your drill wanders off into the softer surrounding aluminum you will have a mess and need to install a thread insert. If you have to start with a crooked hole it makes it very difficult to get the insert installed correctly (perpendicular to the surface and in the right location) without doing it in a machine shop. As far as getting help, I guarantee any decent machinist will have more fix-it tricks and experience for thread repair than most mechanics.

Sharp tap, plenty of lube and patience = a good threaded hole.

For the bolt/thread question, yes the tap should be able to cut the pieces of the old bolt out as the bolt is comparatively soft to the tap but this won't work as well if the parent material is aluminum, the tap could just push(bury) the steel bits into the softer aluminum. One word of warning - if you break a steel bolt off in aluminum it is imperative that you drill DEAD center and straight. If your drill wanders off into the softer surrounding aluminum you will have a mess and need to install a thread insert. If you have to start with a crooked hole it makes it very difficult to get the insert installed correctly (perpendicular to the surface and in the right location) without doing it in a machine shop. As far as getting help, I guarantee any decent machinist will have more fix-it tricks and experience for thread repair than most mechanics.

Sharp tap, plenty of lube and patience = a good threaded hole.

Wow - it sounds like you have experiance with this! ;)

Where would one even find a machinist? Yellow pages?

You can do a google search for "machine shop" and your city or surrounding zip codes or maybe some one in this forum who lives in your area might know or be a machinist.