Bolt drilling tips (1 Viewer)

[namsag]

Well I been prepping the bolts for a week getting ready to install my OME stock kit. I thought I was home free when I was able to loosen all of the rear shock bolts without busting them, but alas the very last dern sway bar bracket bolt broke off in the frame. I'm glad it's not a shock bolt, but now I have to drill it out I guess. Looking for any tips anyone would care to share. Is it realistic to hope to drill it down till it's thin enough to scrape remnants out then chase the threads and use a bolt the same size? And can anyone clue me in on the thread size so I can get a tap? Any help appreciated. Thanks, namsag.

 

[Oakley40]

Lots of broken/rusty bolt removal advise in the 40 series FAQ's Here's one Rusty bolt removal

 

[Warpigg]

Left hand drill bit, easy out, penetrating oil, and heat. Use a thread gauge after

 

[blkprj80]

Build it up carefully with your mig welder. When it cools, it should back right out.
Acetone and ATF is a good penetrating oil.

 

[Golgo13]

Do you have a welder? Worst case, weld the bracket to the frame. It doesn't really need to be bolted on, its just easier for manufacturing.

 

[BILT4ME]

Left hand drill bit, easy out, penetrating oil, and heat. Use a thread gauge after

FWIW you can buy a decent left hand drill bit kit from O'Reilly Auto parts.

Center punch it, then start small and work your way up one size at a time.

 

[shocktower]

FWIW you can buy a decent left hand drill bit kit from O'Reilly Auto parts.

Center punch it, then start small and work your way up one size at a time.

But that will snap off the drill bit. just use a right hand drive/regular drill bit if the bolt goes in the frame so what, I believ it is a 8mm 1.25 bolt PB blaster is great for getting rusty bolts out

 

[namsag]

Thanks guys for the advice. I do not weld, should have learned a long time ago. @shocktower, I was liking the left-hand drill idea after reading around some, can you explain a little more about what you feel is wrong with it?

 

[Warpigg]

Since the bitt sees the same force ethier way I'm curious too.

 

[mudgudgeon]

@shocktower Why is a left hand drill bit any more likely to break than a right hand bit?

The idea of using left hand bits is that as you get to larger drill bits, it bites into the bolt, the force required to cut chips overcomes the friction on the rusty bolt and unscrews it

 

[fz1boxer]

hit the area around the bolt that is broken off,the impact will sometimes break loose some of the corrosion in the threads.
soak it with a good penetrating oil then left hand drill bit.
using this method i have rarely had to use an ease out and the bolt has unscrewed with just the bit.

 

[ccslider]

I found that using a Dremel and diamond bits works very well for those who do not have a welder.

You can buy them at harbor freight for cheap.

I would still try to center punch in the middle and then start dremeling away. You can go slow and recover easier from a mistake like going off center.

I was able to Dremel through an easy out this way in about 10 minutes.

Just remember you safety glasses

 

[whaler]

Had the same thing happen when I did my lift, 3 of 4 bolts broke (rushing with impact gun). I drilled them out with left hand bits and got a Time-sert kit. Worth the money over helicoil.

 

[bigredmachine]

personally I would not recommend using a spiral extractor, they usually don't work when the bolt is heavily rusted and if it breaks (I speak from experience) you will hate your life for a few hours while you grind it out with a carbide burr because the extractor is hardened and you wont be able to drill it out.

best bet is just be patient and start drilling, start small and slowly work your way up. drill slow and use plenty of oil so you don't burn out the bits. spend the money and get a good bit set itll be worth every penny, nothing is more frustrating than trying to drill something out with cheep bits that dull and just polish whatever your trying to drill out

 

[Malleus]

You need to be really careful when drilling out these weldnuts. Toyota used unpiloted square nuts and tackwelded them in place, before assembly. The purpose of the welds was to prevent the nut from spinning during assembly. The design thought process is that the clamping force developed near the ultimate torque keeps the nut in place. This works great during assembly; it sucks during repairs. I've broken several of them working on the rear frame of Malleus the Younger's 80.

The bolts were so rusted that even with a week of saturation with penetrant (50/50 ATF/kerosene and PB Blaster), there was still so much rust that when the bolt was turned, the rust on the exposed threads completed filled the gaps in the threads and the bolts sheared off. Tapping on them, prior to breaking them, only served to break the welds. I've had to cut the bolts attached to free weldnuts. The sheared bolts had to be drilled.

As stated earlier, getting the centerpunch on a flat surface, perpendicular to the bolt centerline is key. Even then, my drilled walked off (and I used titanium coated bits). I have no choice now but to replace the nuts. Some are easy to get at, and I'll probably just regular flange nuts (it's not my truck). The nuts deeper into the frame are really a problem. They were welded in place before the U-sections were joined to make the tube section. If it were my truck, I'd replace the old weld nuts with pilot projection nuts and reweld them.

The piloted design was developed for sheet installations (the material thickness in the 80 series frame is considered sheet, not plate). It tends to stay in place better during manufacturing, and gives a slightly better weld profile. I prefer the piloted designs because in my experience they survive longer.

 

[Malleus]

You can get these from several sources.

(these are the OEM style)
Square Weld Nut - JIS

Square Projection Weld Nuts | Square Welding Fasteners - JHP Fasteners
https://www.fastenal.com/products?r...^Steel$|~ ~|sattr02:^"Projection Weld Nut"$|~
Weld Nuts | Fastenal

Gripco Square Weld Nuts | Stanley Engineered Fastening

This is not an all-inclusive list. Mr. Google has that one.

 

[Malleus]

I should have added that you need to measure the bolt before drilling. Never use a drill bit larger than the minor thread diameter of the bolt (major diameter of the nut). Best practice is to use a size no larger than 80% of the minor diameter. Start with a bit about 1/3 the diameter you want to finish with and move up in stages. Sharp bits are a must. I keep a set of titanium bits just for this type of repair. I don't use them for anything else. They are always sharp and have no trouble eating through a broken bolt.

The remaining body material can be removed with a pick. Clean up the threads with a tap and you should be good.

 

[BILT4ME]

But that will snap off the drill bit. just use a right hand drive/regular drill bit if the bolt goes in the frame so what, I believ it is a 8mm 1.25 bolt PB blaster is great for getting rusty bolts out

I do this all the time. Please elaborate on what will break the drill bit unless you're cocking it sideways or being overzealous and pushing too hard?

Use plenty of oil and don't push too hard and keep it straight. PB Blaster works well as a cutting oil for this situation.

The left hand drill bit kit comes with screw extractors. Do NOT pound them in very hard and didn't NOT twist hard on them. It is possible to break off a screw extractors and that is even worse.

Worst case scenario, drill up to the correct predrill size for that particular screw and then tap new threads over/through the old bolt. You have to take it easy and slow so if the tap catches, you stop, oil and do it again. Don't force it.

Good luck!

 

[JeepinPete]

The bolts on my truck are to the point that the exposed thread is rusted, but the thread in the nut is not. They will loosen a turn or so then get tight. From experience, if I continue to try to back them out, they will snap. Instead, I have found running them in and out with a lot of oil will get them out of the frame. I use a 1/4" impact, run the bolt tight, back it back out maybe a half turn further than the last attempt, spray some oil on it, then run it back in. Repeat the cycle as often as necessary.

Once the bolt is seized, left hand bit isn't going to back it out. Neither will an extractor. A right hand bit might drive it into the frame cavity, but I haven't had any luck doing that either.

 

[Red Merle]

I do this all the time. Please elaborate on what will break the drill bit unless you're cocking it sideways or being overzealous and pushing too hard?

Use plenty of oil and don't push too hard and keep it straight. PB Blaster works well as a cutting oil for this situation.

The left hand drill bit kit comes with screw extractors. Do NOT pound them in very hard and didn't NOT twist hard on them. It is possible to break off a screw extractors and that is even worse.

Worst case scenario, drill up to the correct predrill size for that particular screw and then tap new threads over/through the old bolt. You have to take it easy and slow so if the tap catches, you stop, oil and do it again. Don't force it.

Good luck!

Any ideas other than the burr bit to remove a busted extractor? I broke my first bolt in probably a year last weekend and managed to drive three busted drill bits and an extractor into it. It was for one of the headlight bolts and I don't really need to get it out, but I wouldn't mind if I could get the mess out of there at some point.