Stripped bolt on upper intake manifold

I have one 8mm allen bolt (rear) that is stripped on my upper intake manifold. Looking for advice getting it out. I'm doing the knock sensor harness replacement. Thanks

 

I would

13 Piece Extraction Socket Set | Impact Bolt & Nut Remover | Remove Damaged, Frozen, Rusted Rounded-Off Bolts Nuts & Screws, Bolt Extractor Tool Set with Solid Storage Case.

try these to start. If they don't work, clean it up and weld a sacrificial bit in there and use that. If that fails, grind the head off, remove the manifold and work with the stub.

 

I don't think I could use that because the outside of the bolt ia round. I don't have access to a welder and I can't really fit a grinder in there. I don't want to pay toyota $1200 to replace the harness

 

You could probably JB weld an allen socket in there. Those bolts aren't mega tight.

 

You could possibly use a dremel to cut a slot in the bolt head to make it a flathead bolt. I’ve had to do this with stubborn deck screws before haha

 

I would suggest drilling the head of the bolt off. Then you can lift the intake manifold off you can get vice grips or a bolt extractor on it. If it’s stubborn you can heat it up after the plastic manifold is out of the way. After relieving the tension on the bolt from removing the head, it may come out by hand. After it’s out replace the bolt with a new one for from ace or Toyota. However you end up taking it out, it’s not going to be fun, so get a 6pack to celebrate once you finally do.

 

Those will work on round heads, but looking at it a second time, you may not have the clearance for the wall thickness. The Dremel slot trick may work.

 

If it’s so tight you rounded out the Allen head recess, do you really think a screw driver will get it out? I see broken screwdrivers tips and frustration in your future lol

 

I've had varying levels of success with internal bolt extractors, something like this:

FreeTec 8pcs Water Pipe Screw Extractor Set, Damaged Screw Broken Bolt Remover Set

https://www.amazon.com/dp/B07M9Y8KCF

You could try that.

Usually you have to drill into the stuck bolt/screw beforehand to get the extractor to seat, but you may not have to since it's a socket head cap screw.

 

I'm not confident that you would get enough of a bite just trying to use the cap socket.

 

Do you guys use a cutting fluid when you drill out a bolt?

 

Just use some motor oil and you will be fine. Let the drill do the work and don’t push to hard on it, you will work harden the bolt and wear out your drills. Also start with a small drill and slowly increase the size until the head comes off. Spin the drill motor faster when using a small drill. On the Larger drills reduce the speed of the drill motor.

 

Good info. I’ve only used hand taps and extractors before. I was able to use some old RP Maxfilm as a cutting fluid in those cases but obviously loads were much lower compared to an automatic tool.

 

If you get some left-handed drill bits, it may break it loose.

 

It is corroded at the head. Chances are the threads inside also are--plus factory probably used a loctite-tipped bolt. A dremel cutting tool would fit that tight spot. Just avoid hitting the intake air surge tank. You can lift the intake air surge tank once you cut it. Be very extra careful; that air intake is made of plastic and any accidental trauma to it could give you lean codes. You case is similar to what happened to my 07 Toyota Tacoma 4.0L.

When my fuel injector number 4 burst due to an out of place o ring, and therefore bled gasoline under the engine, I hurried to remove the air intake hoping I could fire it back quickly. I thought I was loosening the outer intake manifold bolt only to find out that I was actually over tightening it! It snapped at the base of the air intake! Before that, I stripped one of the fuel rail bolts. Ordered a used replacement intake manifold from Ebay and removed the old one with the snapped manifold and fuel rail bolts and replaced it with the used one. Also replaced the intake manifold gaskets. Problem solved. For this model you don't have to drain the coolant as long as the hoses under the throttle body are hooked; it is easy to shove it out of the way. Make it sure you clean the mating surfaces of the intake manifold before installing the replacement gaskets. BTW, since you are already there don't forget to clean the throttle body, air intake and mass air flow sensor; check the PCV valve too since you are removing it anyway. Just doing this will add an extra horsepower you thought your truck never had.

If budget allows you to replace the entire intake manifold, you can find spares in a junk yard or salvage auto parts. You will possibly damage the threads on the stripped bolt and worse, crack the intake manifold while drilling. It has loctite. If you are manually dexterous and want to repair, take out the whole intake manifold and put it on a work bench/table. That way you eliminate the thought of leaving metal shards to you lower manifold. You can do what the rest here already suggested. Again, no coolant draining involved here unless you are flushing your radiator or removing the hoses under the throttle body.

I am sharing this based on my experience on my truck, the fix, and the possible options and solutions. I understand every DIYer has a different experience, approach and solutions. Just pick what will work for your truck. Hope this helps.

 

I've found that there's a fine line between pressure and speed, where the drill actually cuts. And slower is usually better than faster.