What do YOU do when your exhaust manifold bolts bust off?

I went after the right side tonight. Two bolts were finger loose, one stripped, one busted off. The busted AND stripped are on the top- the deal threaded sort. Busted off right at the head.

I've had this rig for 5 months and just keep on finding challenges like this every week or so.

 

drill em out and use a "back out" reverse biting bit, or a left hand tap and a left hand bolt threaded into it. If you really mess em up you may have to drill out the hole and install a helacoil.

Not much else you can do. for the stripped one I'd try a grinder on each side and vice grips to turn it out. But if it breaks, you'll have to back it out as well.

 

Good tip with the grinder.

I've slowly been working my way around the manifold this morning. Here's the data so far: Only one of the studs was snapped and it looks like it's just the very tip , maybe 1/8 of an inch so that may be a lucky break. Easy to drill out that bit and replace with a new stud. All 4 bottom bolts are out. The rear two bolts on the top are in there fuggin tight.

I've been PB blasting and tapping them both as I've worked the rest out. Now that they are the only two left I'm more focused on them. Part of the issue is that the 9/16 heads on those bolts are reeeaallll sloppy. I can damn near get a 13mm box end on there.

I figure I'll let them sit a bit longer while I scare up a new set of bolts, a gasket kit, and a heat shield.

Once I get back this afternoon I may have to pull out the torch.

I do enjoy fixing things with FIRE!

 

Sometimes turning them in a little will loosen them up and make it a little easier to back them out. You could also give them a whack with a hammer straight in, sometimes loosens them up. Had a neighbor who welded a large nut onto a rounded bolt head to get a good grip. Good luck.

 

those are all good tips and I've used every one of them!

I was also gonna say using as large a breaker as you can fit usually helps too. I can't tell you how many times I didn't have the right 1/2 drive socket or my breaker bar (or were too lazy to go get it) and muscled on something with a 3/8 ratchet instead, and the end result is usually a snapped bolt, a smashed knuckle, or a rounded off bolt head. Or a broken ratchet, but thats another story...

 

I had to remove a few stuborn manifold bolts before and what I did was file two flat spots as mentioned and used a pair of vise grips. When the vise grips weren't enough I grabbed my 24'' steel pipe with the vise grips for some extra leverage after soaking the bolts in plenty of penetrating oil and lots of cussing they finally broke loose.

OJ

 

I'm not gonna pretend I've never hammered an old jack handle into an oval and slide it over some vice grips!

Thats one "tool" that I used a lot. I wonder where that pipe got to? I haven't seen it in a while.

:-)

 

Ha! That's exactly what I use. Stole the jack bar out of my brother Dodge Raider. It's a great breaker. Not sure what he'll do when he get s a flat?

 

I admit I am in "best guess" territory here.

After day 2 of soaking on PB, tapping, tightening a bit and then trying to loosen, using a breaker bar, and grinding edges on the rounded bolts I had made no progress. I finally took a round that may be stoopid, but one I've traveled before: I sawzalled the remaining bolt heads off and pryed the manifold free.

Now I have two free hanging bolts. See just 'em dangle just above the starter:



Next, I'll put a pair of locking nuts on there and dual wrench them and try to pull them like they are studs. If that doesn't work I'll notch them and try wrenching some more.

The real crappy thing is that the right two receivers in the head have broken off studs in them. Probably 1/4 of stud in each. One snapped earlier, one was worn smooth, was grimy as can be, and was flopping loose in the hat shield. My guess is that the PO left that for me as it looks like it's been rattling around for a while. I'm hoping I can get the holes cleared by just removing the valve cover. If I take the head off this will become a much bigger job.

 

I feel your pain! I still have the grease under my finger nails from fixing this exact problem. For me, I ground the bolt flush after cutting it off, put a really good center punch mark in the bolt, then center drilled it. After that, I drilled a small diameter hole and then followed with the tap drill diameter for the 3/8"-16 thread. My drilled holes weren't perfectly straight, but after I re-tapped it, everything was cool. Have fun, although you won't.

 

If you have access to a mig or arc welder you could thread on a new nut and then weld the nut to the stud at the end, this high and very local heat may be enought to break it loose. There have been alot of good ideas thrown at this, hope one works for you.

 

Did you do this without pulling the motor? I was planing to go rent a 90 degree drill tomorrow to try this for the broken studs. There is just no other way to get in there. Is there? what did you use to drill out?

As for the two bolts. I am definitely going to weld a nut on there. Maybe two nuts for that matter.

If these don't work I'm looking at having to pull the head. Right? That's what's left?

Uuuggghhhh...

 

Good Luck! I had the same thing happen, three bolts with less than an eighth of an inch sticking out of the head. I ended up pulling the motor so I could drill them out.

 

when you weld a nut on do it one stud at a time then wrench it out while it's still hot

 

Dogmantra, I ran into the same problem as you have on a 390 that I had for a while. I was taking mine apart to rebuild it, so I just let the machine shop remove the bolts when they did the valve job.
Once I got the heads back, I ran a drill bit through the holes on the top side and cut all the threads out. Then I ran a bolt all the way through and put a lock washer and nut on the other side. This eliminates ever having the broken bolt issue again.
Doc