Cm871 Incredibly rusted bolts

[rapidisimo]

Does anyone have any good ideas on how I can remove these bolts without breaking them?

[hhow55]

(05-10-2022 )rapidisimo Wrote:  Does anyone have any good ideas on how I can remove these bolts without breaking them?

https://rawze.com/forums/showthread.php?tid=3028

[rapidisimo]

Do the exhaust manifold bolts penetrate all the way into the engine block? Just wondering if I can drill out the broken bolts without pushing pieces into the engine block.

[Nostalgic]

(03-22-2023 )rapidisimo Wrote:  Do the exhaust manifold bolts penetrate all the way into the engine block? Just wondering if I can drill out the broken bolts without pushing pieces into the engine block.

Head, not block, and I wouldn't attempt to drill them out myself unless I had the jig. Freehand, you risk hitting a coolant jacket. A lot of people have luck spinning them out with a pick, but it's easiest to just mig a nut on and spin them out.

[rapidisimo]

Is there a barrier between the bolt and the inside of the head?

[Rawze]

(03-31-2023 )rapidisimo Wrote:  Is there a barrier between the bolt and the inside of the head?

The threaded holes that are in the head for the exhaust manifold bolts are not thru-holes. They do not open up on their far end into the head or block.

One thing that helps keep them from snapping off when they are really rusty like that are use a brass bar + 5-lb hammer to "shock them" before trying to initially loosen them. Can also use an air hammer on them.

[rapidisimo]

So there is no risk of pushing the broken bolts into the head if I drill them out carefully?

[tree98]

Not if your careful. On my 870 the holes were actually tapped about 1/4" deeper than the bolts would go. So in other words there's another 1/4" of threads past the end of the bolt.