Intake manifold stud for carb help
 

After starting my old truck for the second time in 20+ years, I found gas weeping from the carb gaskets. Time to rebuild. When I pulled it off, I found the front studs had been corroded by the exhaust ports. Quite a bit of necking.

Attachment 2177609

Any suggestions on how to remove and replace without breaking them off?
The image is the worst of the two.

Re: Intake manifold stud for carb help
 

Clean off the scaling rust with a wire wheel and then use some heat and PB blaster to try to penetrate the threads , Do it a few times , heat - spray- cool down then grab it with some vise grips and try to loosen it up . Be ready for it to break off because it looks pretty corroded ,if it does grind it smooth and drill it and use an easy out then re thread it . :chevy:

Re: Intake manifold stud for carb help
 

Does not look like it will come out easy. Rust penetrant to start, may take a day or two to soak in. You can hit the stud with a hammer to try and vibrate a little to help soak in. You can take vise grips and try and wiggle it back and forth (tightening and loosening). Once you feel it has soaked long enough, see if it will come out. Work it back and forth if it does start to loosen (tightening and loosening).

If it breaks, grind down to make a flat surface to use a punch for drilling. Center punch best you can and use a small drill to create a pilot hole. You can add more penetrating oil if you drill to the bottom of the stud so oil can seep in. Then drill the hole out larger to the stud size minus the threads. You want to drill the stud only not the threads in the intake.

Usually that will leave just the threads of the stud in the intake and it can be easily be picked out. Patience makes for a hassle free repair.


You can try an easy-out, just be careful not to break that off in the hole.


Bob

Re: Intake manifold stud for carb help
 

Thank you. I'll have to work on that patience part, I'm a certified watch tapper.

Re: Intake manifold stud for carb help
 

vice grips and you are nearly certain to break it so if you can lock 2 nuts on the threads and use a wrench or socket to move it left and right as already said with patience lol

Re: Intake manifold stud for carb help
 

Just a longer version of what Grumpy said;

Not a lot of torque is required to hold the carburetor. Consider leaving it as it. I think it will hold with a new gasket. Confirm the surfaces are flat before using this option.
No amount of penetrate is moving down those rusty threads. At least not till you have at least one heat and cooling cycle on it. I would use a torch and get the manifold area red hot. Let it cool back to room temperature. Now try the penetrate. Build a dam around it and let is soak, for a couple days if you have the time.
I have a set of threaded collets that thread onto the stud and then tighten on the thread. Most don't have such a tool so I would use a vice grip. Double nuts are too east to slip on the stud in my humble opinion. If the area is hot enough you might have a chance of getting it out.
If it breaks off remove the manifold, if you haven’t already. Grind the left-over stud flat. Next step is the most important. Center punch and drill the stud. If you get it in the center all it good. Even it you have to drill it all the way out sometimes you can save the threads. If not, you can Heli-Coil it. If you are not comfortable with and of this, bring it to a machine shop. Don’t drill it off center and then bring it in. Makes there job much more difficult and expensive. With a little luck I have pulled the threads out like a Heli-Coil. You lose all your options when the stud is drilled off center.
If you get the stud replaced it looks like the surface is pretty rough. Might file the area flat or have it machined?
There are a lot of tools that make this job easier. The professionals will have them. A milling machine is just one of the many options. Others are optical center punches that make getting the hole centered a lot easier. Another is Left Handed drill bits.
Best of luck.

Re: Intake manifold stud for carb help
 

They corrode from the heat cross over blowing by them. The hole behind the stud on the right is the culprit along with the other side. So yeah, they're going to baked in

Re: Intake manifold stud for carb help
 

I'd be thinking of an aftermarket aluminum manifold.
That said if you're in love with a 2-barrel iron manifold, I'd clean the rust, penetrating oil (not WD-40) over and over, let it sit, repeat, let it sit for a long time, then an A/C torch, then more PO, repeat, then shear the stud off and say crap.

Re: Intake manifold stud for carb help
 

:lol: Man, ain't that the truth! Done it many times.

Re: Intake manifold stud for carb help
 

Franken nailed it. LOL. Good one.

Re: Intake manifold stud for carb help
 

You maybe opening a can of worms, the threads look good enough to hold your carb down, they don't need to have a lot of torque

The manifold surface looks very pitted, I would try to get that flatter, or look around for a better manifold

Have one on hand, so when you snap the bolt you can move on and replace it. I don't think I have one or I'd send you one

Re: Intake manifold stud for carb help
 

Thank you all, I love the exchange!

I'm not too worried about the flatness, I have not cleaned up the old baked-on gasket remnants yet. As some have suggested, I was considering applying an ablative around what's left and just leaving it at that. I might be able to pick up some good stuff at work.

Too many times I have been in the situation Franken put so well, which is why I asked before jumping in.

This old truck is very original, been in the family since its birth, so I'm not convinced yet that I want to stray far from that.

Re: Intake manifold stud for carb help
 

Agreed.....for anything non-performance I'd stick with the 2bbl also. Just take your time and soak those for a few days and maybe at the same time get some heat on them. Go slow and work them back and forth

Re: Intake manifold stud for carb help
 

If push comes to shove I have 3, 2 barrel manifolds with good studs.

LockDoc

Re: Intake manifold stud for carb help
 

Patience Patience Patience Patience.

It is the key. Whatever method you use to grab the stud have a clear view of the stud before trying to twist it.

After heating and applying pentrating oil. Lightly turn the stud watching carefully to see when the top starts to twist even though the bottom is still stuck. Do this back and forth without trying to turn the bottom of the stud. It may not look like you are making progress but you are creating micro-cracks in the rust around the threads which will allow the oil down around the threads. After twisting the stud top 5 or 6 times STOP and let it sit for a couple hours. Add more oil if it runs off.

Then repeat the process. It may take 3 tries or 19 tries but it should eventually come loose. Keep being patient moving the stud lightly back and forth. If you try to force it it will twist off. Flushing the area with pentrating oil to try and wash rust from the threads will help.

If you lose hope, try pulling the manifold to see if you can see the bottom of the stud. If so soaking that area will help but only if the stud hasn't been twisted off.

Remember when heating the manifold you don't want to heat the stud. You want the manifold to heat up and slightly expand the hole. If you heat the stud it will expand and get tighter in the hole. So heat the area around the stud, apply oil and twist the stud before the heat from the manifold transfers to the stud and you lose the temperature difference. Then wait for the manifold to cool before trying again.

Good luck.

Re: Intake manifold stud for carb help
 

Ya know, this stuff was easy-peasy, 40- 50 years ago. Amazing what rust can do in the meantime. :lol:

Re: Intake manifold stud for carb help
 

PB blaster night before then Put some heat on the manifold where the studs thread in. Your not heating the stud but rather what is threads into to expand it.
I bet they spin right out with vise grips.
Propane hand held torch is plenty. A little heat works wonders!
I bet you a 12 pack and cheeseburger she spins right out of there.

Re: Intake manifold stud for carb help
 

Try as GOM says, you may also try the heat, and melt paraffin wax into it as you TAP the stud to cause vibration, which allows the wax to seep down into the threads, IF they aren’t completely fused together with oxidation.
Be VERY patient with trying to get it to come loose, because it looks to be retry corroded.
If it breaks, Again do what GOM says, and go slow.

Re: Intake manifold stud for carb help
 

I think I might be down a 6 pack & 1/2 a cheeseburger. One of two spun right out after GOM, et al. direction. That was the more robust of the two, I'm being a bit more cautious with number two.

Re: Intake manifold stud for carb help
 

Double nut it.
Apply some air hammer

https://fb.watch/bT7exdtR7D/

Re: Intake manifold stud for carb help
 

I would clean the base apply Kroll or PB blaster tap the stude every so often . Then use heat on the manifold cool and start over . Double nut it and tighten slightly then back out slightly and repeat .

That being said you might just want to brake it off drill and use heli-coil be faster

Re: Intake manifold stud for carb help
 

I like the air hammer idea. I sometimes use a screw gun with an a socket adapter. The hammer action really works well. A bigger air hammer will just break it off. Even turned down they can be unpredictable. Why the screw gun is effective. Some great ideas here.

Re: Intake manifold stud for carb help
 

The problem child has been removed.

Attachment 2178813

Repeated heating/PB with Vice Grip forward & backward small motions finally allowed it to move this morning. I knew I had it when the PB actually seeped in instead of simply beading along the interface point.

Thank you ALL!


Now my father inlaw says back in his dirt-track days they would just stop up those holes from the exhaust, nothing good would come of those anyway.

Re: Intake manifold stud for carb help
 

:cf: :wave:

:burnout:

:chevy:

Re: Intake manifold stud for carb help
 

It was an emissions thing, supposed to help heat the carb. We used to run a 1/4'' pipe tap in the hole and screw a plug into them. Same on the 4bbl