When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Remove broken exhaust manifold bolts with engine in truck
Has anyone had experience removing or drilling out and rethreading broken exhaust manifold bolts without removing the heads?
I am installing headers on my 62 F100 with 292 yblock. A couple bolts are already broken and when I take off the manifold I'll probably break more. Just want to know the easiest process for a person with basic tools. And basic work space. That is, I dont have a machine shop or engine lift. I was thinking i could get a 90° Drill adapter and drill out the bolts and rethread.
How hard is this going to be with heads on the engine in the truck? Are there any precautions I should take? Drill depth? Covering manifold openings etc?
Before breaking any more bolts use heat, penetrating lubricant, heat, penetrating lubricant....etc. over and over. Let it set a few days before torqueing any more bolts off. If the bolts broke flush with the exhaust port, you will have to drill them and use an easy (not easy!) out. Otherwise drill them in the dead center with a small drill and step up one size at a time until you can burn the threads out or re-tap. Remember heat beats muscle on these. If any metal extends out past the exhaust port, you can weld a nut onto the stub. The heat will help loosen the stud and you will have something to put a wrench onto.
Before breaking any more bolts use heat, penetrating lubricant, heat, penetrating lubricant....etc. over and over. Let it set a few days before torqueing any more bolts off. If the bolts broke flush with the exhaust port, you will have to drill them and use an easy (not easy!) out. Otherwise drill them in the dead center with a small drill and step up one size at a time until you can burn the threads out or re-tap. Remember heat beats muscle on these. If any metal extends out past the exhaust port, you can weld a nut onto the stub. The heat will help loosen the stud and you will have something to put a wrench onto.
Resonateur,
I'm going to do my best not to break any bolts. When I got the truck there were missing bolts from the manifold. I might get lucky if those bolts are just missing, but I'm preparing for the worst case scenario here.
I have a propane torch, should I use that or just crank it and let it heat up on it's own?
I haven't had to try it thankfully, but I just read this the other day and bookmarked it, I thought it had some good tips. I found it rooting around on a mostly electrical related website about setting up alternator charging systems. Need left hand drill bits, and a good quality (torque) variable speed reversible drill.
You are kidding yourself if you think you can get those bolts drilled out accurately without head removal.
That said, I have had extremely good luck welding on a nut to the broken bit, then just turning it out. The heat of welding breaks the bond of rust.
I have not tried, though I know people who have done it, but you can also torch out the bolt without damaging the head, because cast iron has a higher melting point than the bolts.
This you might be able to do in situ.
Please do this correctly, because Y-block heads are getting hard to find.
Propane may not develop enough heat on those heads. For some reason, I was picturing the FE head but after reading Cosmo’s comments and realizing it’s a Y block, he has a point. Those will be more difficult. I would doubt that a 90 degree drill adapter would be very efficient or accurate. Its a difficult job, even on the bench.
Cosmo can sleep well tonight because I didn't break any bolts! And the real miracle was that of the 3 missing bolts only 1 of them was broken in the head. Not ideal but for now I'm going to leave it alone. It's in the middle location, so beat case scenario for a broken bolt.
I have been putting this Blaster to those bolts for days and they turned so easy it was freaky.
Just a word about the headers- they didn't fit. If anyone is thinking about buying the Patriot headers that supposed fit the y block F100, don't. It needed to be about 3/4 to 1 inch lower to clear the crossmember.
Last edited by Knockonwood; 05-16-2019 at 10:06 PM.
Reason: Grammar
Did you tweak them or send the back?
I used a set of ancient NOS "1957 Ford Car aftermarket tube headers" on my '63. These were not long tubes. They actually run parallel to the head and are a single tube design. They turn down in front of the firewall. They fit perfectly and posed no problem for the muffler shop.
I do believe Red's still makes this design.
Did you tweak them or send the back?
I used a set of ancient NOS "1957 Ford Car aftermarket tube headers" on my '63. These were not long tubes. They actually run parallel to the head and are a single tube design. They turn down in front of the firewall. They fit perfectly and posed no problem for the muffler shop.
I do believe Red's still makes this design.
F-ONE,
I "tweaked" them with a propane torch and 2 lb hammer. I looked at Red's Headers. I actually wanted those, but decided to go with Patriot because they were 3" collectors and Red's were only 2.5". I'm bolting on a set of turned down glass packs directly to the headers and needed 3". In retrospect, I should have just gone with Red's and took my truck to a muffler shop.
05-13-2019, 03:44 PM
