So, what did you do today?

[marshall_mosty]

Need some advise on bolt extraction.

When my three link mount let go, the second diff mount bolt (was using one of the cover bolt holes) sheared off. I tried small RH drill bits with no luck. I think this is a metric grade 8.8 bolt so it's pretty tough.

I've ordered some 1/8" center drill bits and then some LH bits. I also have easy out's once I have the hole drilled.

Are there any other techniques other than:
1. Center drill
2. LH drill bit
3. Easy out

??

[Supercharged111]

Need some advise on bolt extraction.

When my three link mount let go, the second diff mount bolt (was using one of the cover bolt holes) sheared off. I tried small RH drill bits with no luck. I think this is a metric grade 8.8 bolt so it's pretty tough.

I've ordered some 1/8" center drill bits and then some LH bits. I also have easy out's once I have the hole drilled.

Are there any other techniques other than:
1. Center drill
2. LH drill bit
3. Easy out

??

Weld a nut to what's left and spin in right out. Works insanely well.

[marshall_mosty]

Weld a nut to what's left and spin in right out. Works insanely well.

The bolt broke off below the face of the diff, so there is no way I can weld anything unfortunately...

Craig,
I'll certainly use some heat on the housing before I try and drill/spin the bolt out.

[Casey_SS]

The bolt broke off below the face of the diff, so there is no way I can weld anything unfortunately...

Craig,
I'll certainly use some heat on the housing before I try and drill/spin the bolt out.

Is there loctite on the bolt? If so, you'll want to heat the bolt itself to loosen that stuff up. Probably also want to heat the housing around the bolt to equalize whatever thermal expansion you get from heating the bolt. Without the head, there shouldn't be any torque on the threads aside from any loctite resistance. Maybe try welding the tip of a smaller bolt to it and use that as a handle to spin it out. If it's really down in there, just keep adding tiny spot welds in the center of the bolt until you build it out enough to get to it without accidentally welding it to the case.

[Supercharged111]

My cousin welds washers down there when he needs to get a stack going.

[edrock96GT]

What Casey said. My shop dispatcher has gotten really good at spot welding enough of a bead that you can build it back up past the surface and then weld a nut to it. We've broken a few exhaust bolts on older cars in our shop.

[dtanker65]

Grind a small divot in the center of the broken bolt with a small Dremel carbide burr so the drill starts centered. Drill a shallow hole with a cobalt bit for an easy out (the stubby snap on easy outs are best) If you use a hardware store easy out, grind the tip off until it fits the shallow hole. You don't want to break the easy out or drill off in the bolt. Once you have good bite with the easy out, heat the housing until the bolt unscrews with light torque.

[Trublu]

Need some advise on bolt extraction.

When my three link mount let go, the second diff mount bolt (was using one of the cover bolt holes) sheared off. I tried small RH drill bits with no luck. I think this is a metric grade 8.8 bolt so it's pretty tough.

I've ordered some 1/8" center drill bits and then some LH bits. I also have easy out's once I have the hole drilled.

Are there any other techniques other than:
1. Center drill
2. LH drill bit
3. Easy out

??

Heat the area around what's left or the bolt (called a Dutchman where I'm from) then use a small cold chisel to back the Dutchman out. Heat is your friend