How to remove a broken bolt flush with the crankcase

[Paul Fithian]

Here's how to remove a broken cylinder bolt that is flush or below the surface of the crankcase


Get a washer about the same ID as the bolt and weld it to the top of the broken bolt. Remove the ignition coil before welding


Add a second larger washer on top of that and weld it to the first washer/bolt


Quench with a water spray, then grab onto the second washer and unscrew the bolt


This bolt was blue Loctitied for 48 hours and came right out.

 

[Chainmale]

I like it. That second washer gives enough gap to grab onto a bit better

 

[Duane(Pa)]

Good poast

 

[misterhandyman]

Ive always welded a nut to the broken piece. Then you have a good way to grip it

 

[Paul Fithian]

Ive always welded a nut to the broken piece. Then you have a good way to grip it

Agreed, one of the things we learn working on older Ford 4.6/5.4 V8's with broken exhaust manifold bolts.

For this one, almost none of the bolt was above the surface, the washer trick let's you get closer to the bolt to weld on it. With the second washer on top, it is easy to grip with a pair of pliers and rotate.

 

[cus_deluxe]

nice! as another option on those i usually have good luck with left hand twist drill bits.

 

[Paul Fithian]

Thanks fellas! Tried the LH bit first @cus_deluxe , didn’t work.

Real easy to damage the milled surface on these, which is why I went with the welding option

 

[Sawpaw]

Here's how to remove a broken cylinder bolt that is flush or below the surface of the crankcase
View attachment 392514

Get a washer about the same ID as the bolt and weld it to the top of the broken bolt. Remove the ignition coil before welding
View attachment 392515

Add a second larger washer on top of that and weld it to the first washer/bolt
View attachment 392524

Quench with a water spray, then grab onto the second washer and unscrew the bolt
View attachment 392525

This bolt was blue Loctitied for 48 hours and came right out.

Excellent post, much appreciated.

 

[av8or3]

Well done!

 

[hacskaroly]

Here's how to remove a broken cylinder bolt that is flush or below the surface of the crankcase

I wish I had seen this last week...I did a bad job trying to drill out a broken screw from my 066 case.

 

[davidwyby]

Cool a little...then soak with Kroil, let the heat draw it in. Then cool the fastener completely before removing. Helps if the case is still hot. Repeat as many times as necessary. Washer, then nut. Use a small impact driver very lightly for a minute or two to work it back and forth until it comes out.