Need Help - How to drill out a hard bolt?

[Travelover]

I'm replacing the flex pipe on my Escape where it attaches to the 3 bolt flange at the catalyst. Unfortunately in spite of precautions, I've broken off two of the studs. The bolts are very hard and I'm not having much luck drilling them. I ground off the "head" of one of the studs, but it won't drive through - at least not at the level of force I'm comfortable with. Suggestions?

One photo is the face of the flange with broken stud, second is the back where I ground it.

Thanks in advance.

 

[dieselknudt]

I would try heating the metal around them and then pound them out.

 

[Mysfyt]

Here's a second vote for heat. Also use a flat tip punch so it doesn't 'mushroom' the stud when striking it. And speaking of striking it, that first hit means a lot!

 

[Travelover]

I would try heating the metal around them and then pound them out.

I hit it with a Mapp torch - all I have and hit it as hard as I dared - no movement. Don't want to ruin the catalytic converter.

 

[Big Barn]

The trick is usually to get the surrounding area good and hot quickly then pound the stud out before it gets a chance to expand. Maybe try again... Terry

Hotter torch oxy/fuel and bigger hammer

 

[Travelover]

Success!

OK, everyone can relax now :laughing:

I did manage to pop out the broken studs after grinding the backs off. Since I don't have an oxy- acet torch anymore, I took my 4 1/2" grinder with a cut off blade and cut a slot from the edge of the flange to the stud. This released the grip on the stud a bit and I was able to smack the face of the broken stud with a flat punch to drive it out. I don't think the slots will affect anything as the gasket seals inboard of the slit and the new bolts provide a good clamp load.

Lesson learned for me is to just grind the nuts until they split and then replace them rather than trying to see if they will come loose with enough penetrating oil and torque.

Time for a beer.:drink:

 

[RPW]

After getting it hot shoot some WD40 yellow can directly on the broken stud. The heat will cause the oil to be pulled into the joint then smack it hard. One thing not mentioned is to be able to brace the flange when striking to prevent breaking the flange.

 

[skyhook]

After getting it hot shoot some WD40 yellow can directly on the broken stud. The heat will cause the oil to be pulled into the joint then smack it hard. One thing not mentioned is to be able to brace the flange when striking to prevent breaking the flange.

Good point, putting a socket around the area and letting the bolt fall into it will help in support.

 

[brown40]

Wax has helped me when penetrating oils can't seem to--has to be on the cool side or wax will flow right off. Turbosockets keep biting until there's no more metal to cut into. I try to be patient and heat and lube whenever they seem to be near failing, but its nice to know if I twist it off I can still hook into any exposed metal and keep turning it.

 

[SandburRanch]

Your drilling was hindered and the bit suffered by the lack of cutting oil