Exhaust Manifold Bolt Blues

[mlcraven]

So what's the latest thinking on getting these SOBs out when the head shears off? Heat? Penetrating oil sure as heck isn't making a dent in the problem.

I was lucky, only one out of sixteen manifold bolts (#4 cylinder) and one of two engine hoist bracket bolts (#3 cylinder) let go. Hammering a one-size smaller six-sided socket (half-in) onto badly rusted and mainly stripped bolt heads got the others off without too much trouble.

[min301]

Heating, quenching, and soaking with PB Blaster or the like will be your best friend.

[Barry_R]

After you get tired of rounding them off you'll cut them flat & smooth. Center punch them. Drill a very carefully centered small diameter pilot hole. Then drill them out to the specified minimum diameter for a 3/8 tap. Retap and repeat. I have Willie do them on the Bridgeport - probably a couple each week. You can do them with a block of scrap drilled as a 90 degree fixture to keep the bit going in straight....

[tardis454]

PB Blaster & heat works good in most cases, but you do run the risk of oil hardening the stud making it more of a pain in the ass to get out if it doesn't budge on the first few tries...

An old farm trick I use for badly stuck & rusted studs/bolts is heat & a stick of paraffin wax.

Clamp the vice grips on the stud beforehand, you'll want to turn the stud immediately after you hit it with the wax.

Heat the stud up red hot, quench it with the wax stick, & turn that S.O.B.ing stud out.

That trick has worked for me EVERY TIME...

[mlcraven]

After you get tired of rounding them off you'll cut them flat & smooth. Center punch them. Drill a very carefully centered small diameter pilot hole. Then drill them out to the specified minimum diameter for a 3/8 tap. Retap and repeat. I have Willie do them on the Bridgeport - probably a couple each week. You can do them with a block of scrap drilled as a 90 degree fixture to keep the bit going in straight....

Barry: thanks for that. And for the FE book; that's some real gold right there.

[mlcraven]

Thanks guys, I'm gonna give the heat and wax deal a try and if that doesn't do the trick follow Barry R's directions.

[min301]

Which would have been my next recommendation, cut flush,
center punch, and drill and tap.

[BOOOGHAR]

I have this set in standard and metric - they've worked wonders on bolts like that

http://matcotools.com/catalog/product/MBX5/5-PC-1-2-DR-BOLT-EXTRCTR-SET/

[Mater]

Which would have been my next recommendation, cut flush,
center punch, and drill and tap.

had to do this a few vehicles at the dealer when a stud breaks (they always break) on a 4.6/5.4 but it sucks more becuase it's aluminum

[Ron Ward]

Man, if you have access to a welder, put a flat washer over the stud and then place the next size larger nut over the stud and shove it up against the flat washer. Weld the nut to the stud. The heat from the weld will break the stud loose and you will be able to zip it out with an impact wrench.


Ron

[TheSilverBuick]

I have this set in standard and metric - they've worked wonders on bolts like that

http://matcotools.com/catalog/product/MBX5/5-PC-1-2-DR-BOLT-EXTRCTR-SET/

My Dad had a set of those in all the tools he gave me when he retired. Must be good stuff for heavy machine mechanics?

[SpiderGearsMan]

I have a set of stahlwille stud sockets that would take care of that

ever mod motor ford truck we get in has broken manifold studs

[STINEY]

Unreal..... I just finished taking out all the bolts on one side of my 390 FE project.

Kids birthday candles are a easily accessable source of wax, I find them in with the wife's kitchen stuff.

When you can get to it (like on the flange of the FE exhaust) I prefer to heat the cast iron instead of the stud/bolt. It took 2 heating/cooling cycles (no quenching!) before the manifold let loose of the bolt, and on the third cycle vise-grips and wax barely started to budge the threads loose.

Be patient, and work both ways, loosen a bit and tighten a bit. If you do only loosen you will twist it off again. Use wax, just touch it to the tread area and watch it dissappear. If it smokes off instead of penetrating, wait a bit and try again.

It took lots of little "bites" with the vice-grips to get that one bolt that is recessed next to the exhaust dump flange, but it came loose easier than the rest for me.

Still have to do the other side, that manifold was cracked in 3 places, so a pair of hammers broke it up and off the remaining bolts. I had already cut the heads off with a cut-off wheel, that helped a bit.

Ready for another round of heating and waxing this weekend!

Good luck! That WILL come out, keep at it!

[Teddyzee]

I've had no luck with candle wax and heat last time I went through this.

Once I eliminated the little nub through various vice grip/nut welding adventures, I just drilled and tapped the bolt.
A hardened bit (cobalt tipped, I believe?) will go through with ease.
More than once, I found the tap will actually loosen the remained of the original bolt as I eased it back and forth.
I've had no luck with bolt extractors (the left handed things). The cobalt bit has no problem drilling through those, too...

[TC]

Smack the end of the stud with a hammer a few times spray it down with PB Blaster, let it sit overnight, then smack the end of bolt with a hammer again, lock a set of vice grips on it or use one of the stud removal tools posted earlier.......The stud should come right out......