1999 S70 One of these head bolts is not like the others.

Post by **Brucebo** » 03 May 2015, 19:00

By the way, who is the recommended shop nowadays for rebuilding your Volvo head?

: Broken head bolt

Post by **E Showell** » 03 May 2015, 19:59

Been there, done that. Easy out is your best friend after finding a good, sharp reverse handed drill bit.

Post by **erikv11** » 03 May 2015, 21:04

Ugh. Sorry to see that.

Check this out regarding rebuilt heads: https://www.matthewsvolvosite.com/forums ... =1&t=69336

Post by **Brucebo** » 03 May 2015, 21:17

Scuttlebutt on the web is, once the top of the bolt is broken off, tension is removed from the threads, so it should not be too difficult to remove the stub with a reverse drill and/or an Easyout. I currently have the hole filled with Liquid Wrench. I also put an exact diameter transfer punch down in the hole and tapped it with a hammer to put an exactly centered starter hole on top of the stub for the drill. I also plan to put a steel bushing in the well to keep the drill bit centered and protect the sides of well.

Post by **E Showell** » 04 May 2015, 11:28

Transfer punch and bushing both good ideas, but I am here to tell you that a good, sharp reverse threaded drill bit will be your best friend. A good cut followed by an easy out of the proper size and you'll be good to go. Just move deliberately and carefully and you should be fine.

Post by **E Showell** » 04 May 2015, 12:40

Let me guess. Back side of engine, i.e., adjacent to firewall, between cylinders 2 and 3 or 3 and 4?

Post by **Brucebo** » 04 May 2015, 13:32

Let me guess. Back side of engine, i.e., adjacent to firewall, between cylinders 2 and 3 or 3 and 4?

Exactly! Must be not too uncommon.

Post by **abscate** » 05 May 2015, 01:39

Anything one can do here to prevent this nasty? Maybe getting penetrant down the threads before loosening?

Post by **Brucebo** » 05 May 2015, 10:35

abscate wrote:Anything one can do here to prevent this nasty? Maybe getting penetrant down the threads before loosening?

How would one do that? Before loosening, the bolt head flange is tight against the top of cylinder head. No way to get to the threads. I suppose someone could design a head bolt with a small cylindrical hollow center shaft to serve as a temporary oil galley, with small radial galleys going out to the threads. To be filled with PB Blaster prior to removal.

Post by **abscate** » 05 May 2015, 10:54

You can get penetrating oil to tight threads with...

Time
heat
Reasonable application of shock - rattling the bolt with careful taps