Broken Riser Bolt

So I decided to replace the riser gaskets, as expected one of the bolts snapped. So I have new grade 8 bolts but I can't get the old one out. So what kind of drill bit will go through these. It's broken off flush. I tried a bolt extractor, and allot drill bits and the hardest I could find was cobolt and does not phase this bolt. After many hours using diffent small bits and oil I'm barley drilled down. So for people that had to do this how did you the bolt out. Thanks in advance

nope no welder available

I would have tried that if I had a welder, I'm sure it's stuck from all the rust over the years. I tried heating the area around the bolt with a torch with no success. I'm not sure what I'm going to do know short of replacing the manifold.

I'm having a hard time finding a Carbide bit in Orlando,seems the ones I do find are for a hammer drill for concrete.

I give it a go with a good cobolt drill, if the USA is like the UK unless you go to a good engineering supply store your find most drills from a DIY store are poor quality, don't fall for the coated drill bits and if your using a hand drill needs to be variable speed on the trigger, not a standard fixed speed drill.

May have to get a carbide drill bit on line look on Ebay or these guys have them, no safe cracking after you fix it

Carbide Drills

Keegan I would run the engine up and get it up to temp then drain and have a go at the bolts, have a look to see if some thread ends are exposed outside the block if so a squirt of, releasing oil your names are different to ours, Pete likes something called Kroil have tried to get some here but its only available from an oil rig supply company in Scotland and will not post pick up only but sound like its good stuff.
When you try the bolts just don't over do it on the wrench if stuck try and soak it overnight or add some heat from a gas gun, Make Sure The fuel lines Are Well Away.

Back to the carbide drill if you have or access to a diamond face grind wheel buy a masonry carbide tip drill and regrind to cut steel, could work for just one bolt.

Yes drilling out a broken bolt is not fun at all. Especially in an exhaust manifold. Some tricks to try first heat the bolt with a propane torch but use MAP gas if you can, it gets hotter(red bottle).
Then hold a candle on it the idea being to melt the wax down into the threads, then if it starts to move it will be easier to get out. The best drill bit to use is a cobalt content bit not cobalt tipped there is a difference. Also left hand twist that way if the bit does catch it will turn out the bolt. Also start with a small bit and work your way up start at 1/8". Slow slow slow is the word so you do not over heat the bit. oil helps. Now if none of that helps the next step to try is to get on the top of the broken bolt with a carbide cutter I use them in my air die grinder but if you have a dremel I think that would turn fast enough what we're trying to do is remove the first part of the bolt that has been drilled and possibly over heated. Bad news is it's the exhaust it's already been over heated!! Right. But the next step is to remove the manifold and take it to a machine or welding shop and hoe they can get it out, and it comes off good. Good luck I have had good luck with all of these procedures and I have had not such good luck also.

Tom

So it's looking more like replacing the manifold now. I have one last attempt with a carbide drill I found at a local shop. Question is I have two of the bolts for the manifold that did not break loose. I don't want to apply allot of pressure after my experience with the riser bolt. I soaked them with some PB Blaster, what else should I do before attempting to remove them. I will also apply heat around them too before attempting again.

Thanks

That's good info the penetrating oil. I guess I will look for some kano kroil, I do have liquid wrench already.

Nope don't use fram filters

jayc wrote: I thought it would be a complete nightmare. grade 12 bolts and new spring washers.

I hope you used never seez or copper slip or next time it will be

grade 12? titanium? lol

eric lavine wrote: grade 12? titanium? lol

Eric,
The 12.9 is a Euro grading. It's the highest strength and about equal to our grade 9 (180,000 tensile)

JLags wrote: Bad news is still can't get that bolt that broke out,

Not given,
You have work hardened the broken bolt by spinning and not cutting with drill bits. Even with a carbide bit and with the manifold set up in a drill press for the drilling pressure needed on the bit, you will stil have a problem cutting through the hardened surface. This is why I suggested EDM burning it out. It's ether that or getting a new manifold and riser.

I think you can use stainless for the manifold to head bolts (I know I do without any issues) but the riser bolts think shold be high tensile and threadlocked otherwise they can go loose and cause gasket failure.

At least that's what I've read on manufacturers websites and various forums.