89 B-700 Exhaust Problem -- HELP!!!!


anomaly_va_1976
01-11-2008, 02:19 AM
Hi all ---

89 Ford B-700 (read: Long Frame F-700 with a bus body) , 429-4V...

The problem I'm having is that the driver's side exhaust manifold cracked (I understand this to be a common problem with 370s and commercial 429s) -- Bought a new one (from A-1 Auto over the InterNet if anyone needs one, about $90 each) and when I removed the old one, five of the studs broke off in the cylinder head.... :eek:

Does anyone have any ideas on how to get them out? I can't put the new manifold on until I fix this. Fortunately, I don't HAVE to have the thing fixed right away, it's being used as a mobile surveillance office. Any help would be greatly appreciated.

rhandwor
09-20-2008, 03:46 PM
If they're broke off flush I have center punched them. And used a 5/16 inch drill bit. I then used a 3/8 inch tap and retapped the hole. This is assuming cast iron heads and 3/8 inch studs or bolts. If you have something to work with I soak them with P-B Blaster and use a stud remover,tap good with a hammer before starting. Some people use a thick steel washer with a hole about the same size as the broken bolt use a mig welder and fill with weld. Then weld a nut on the washer and remove. I have tried to drill a small hole and use an easy out but have had them break which causes a worse problem.

MagicRat
09-23-2008, 08:55 AM
I have tried to drill a small hole and use an easy out but have had them break which causes a worse problem.
I agree here. You should assume the broken studs are really stuck and an 'easy-out' will break too.
I have seen mechanics use an oxy-acetylene torch and a wet rag to heat up the cast iron surrounding the broken stud, which helps loosen it up and the head can be removed.

IMO if there are that many broken studs, it might be easier to remove the cylinder head and take it into a machine shop so they can remove the studs.

Add your comment to this topic!