VetteDrmr

I know, it's not C5 specific, but I think its applicable, and I'm in trouble! I'm also going to post this in the C4 Tech section, because I'm looking for all the advice I can get. I've got two exhaust manifold bolts broken off, both on the #7 exhaust. Looks like one has been broken for quite some time (maybe before I bought the car 2 1/2 years ago), while the head of the other one popped off this week.

As tight as the other bolts have been coming out, there's no way I see other than pulling the head to get these babies out. But, once I have the head off, how do I go about getting them out? My Helms manual was of NO help (first time it's totally let me down). The customary answer is that you use heat to loosen up a joint, but that advice has always been for steel on steel joints. What about aluminum on steel? What about warping the head?

I do virtually all the work on my car, but I'm not sure I'm up to this one.

Thanks for any help,
Mike

vettenuts

Mike,

If you are pulling the heads, take it to a reputable machine shop. They can get the broken stud out of the head. I wouldn't attempt this one myself as getting a steel bolt out of aluminum can be very tricky without the proper tools and fixtures. Good luck, hope it turns out OK.

VetteDrmr

Thanks for the quick reply. I'm definitely pulling the driver's side head. I was thinking about helicoiling the two studs. Is this what you're describing a machine shop as being able to do? Or, do they have some other capability that I don't know of?

Thanks again, and have a good one,
Mike

MDT

VetteDrmr,

Every situation's different. Sometimes the portion left in the head is not very tight.

In any case, the way I have always handled this is to carfully center a pilot hole with a small drill bit and drill through the broken stud. Then go to a little larger bit and drill through the stud again until the hole is nearly as large as the stud. Then buy a proper sized E-Z Out and place in the hole and see if it will allow you to unscrew the portion of the stud that is still in the head.

The Hele-Coil procedure is always a last resort if the above procedure isn't fruitful. If you don't want to mess with the E-Z Out, I don't think that a machine shop will charge too much to get the broken studs out.

Good luck.
Mark

pjazz

Years ago I broke off an exhuast manifold bolt. I took the head to a machine shop and they took it out no problem. I never really asked how they did it, but it was a cast iron head. If you get a reputible shop I'm sure they could do it no problem.

aces

Use left handed drill bits and sometimes it comes out without the ez out.
Also, inserts usually work far better than heli-coils.
my.02
:cheers:

indyblue98

If You are going to attempt this Yourself ,, the one additional item I would suggest along with the other items above.. before You start with the drilling on the old broken bolt go to the parts store and buy a can of penetrating oil
and position the head on a bench or whatever it takes so that gravity will
help the oil to work around the bolt. Let it set for at least 4 hours. Lastly try to use a reversing drill motor and get a left hand turning drill bit., then use the e-z out as mentioned already. Even if You end up having to get a shop install the heli-coil ,This proceedure will only cost about $10-15 and You maybe one of the lucky ones. I have done this before and actually had a bolt come out as I was trying to drill the hole for the e-z out. Fingers crossed :seeya

vettenuts

I attempted this once without the proper jig. Drill slipped and of course it cuts through aluminum like butter.