What is the best way to remove rusted steel bolts in aluminum (1 Viewer)

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Jan 7, 2016
Curious what methods you all use for removing rusted steel bolts in aluminum. I need to replace my passenger side exhaust manifold on my 100 and the bolts are extremely rusted after 17 years in the northeast. I have read through the threads on exhaust manifold removal and replacement. I attempted the drivers side when I first purchased the truck (2015) I removed 4 bolts which came out with the nuts then I broke 2 different universals on my ratchet trying to remove the rest of them thus the truck went to Toyota to finish the job due to a time restraint.

These are methods I have used to remove rusted steel bolts in steel
1. Repeadedly soak with Kano Kroil working bolt in micro turns in and out
2. Adding heat with a torch sometimes works as well
3. Using a special tool I made with an air hammer

Other methods to consider I have not used
4. Using a small 3/8 impact or air ratchet
5. Letting engine run approx 1hr then try to remove bolt when hot
6. Using an 18v impact gun with a socket adapter

What do you all think is the best method to remove these manifold bolts?

This is a picture of the tool I made to remove rusted bolts, ( shown with slotted 3/8 drive socket) which works well but I can not use it for this application. The new bolts will be installed with anti seize.

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You can try dissolving it out with a chemical reaction that dissolves steel, but not aluminum:
Good suggestions on your list.
Mine has a lot of rust, so I come across it a lot.

Yes, soaking it in something, even repeatedly over days if really bad, works quite well.
I've normally used wd40, but there's a lot of things out there that would do the job.
As does heat.
I agree with running the engine for a while first, so its hot.

Sometimes, if a bolt won't loosen, turning it just a bit, clockwise, i.e. tighter, first, can help free it.
If the bolt shears off proud of the surface, sometimes multi-grips or similar work well, or else cut two straight sides with a grinder and attach a spanner.
Or, a stronger method would be to weld a nut to the top, and then use that to undo it.

If the bold shears off level with the surface, then that sucks, and the above suggested method of using acid sounds good, so long as the bolt you are removing isn't located upside down, etc, unless you can turn the car over. :)
And also make sure the acid cannot leak into any other part of the engine, inc gaskets, etc.

Another method is use a centre punch to indent the centre of the broken top of the bolt, and the drill, with a very small, good quality steel bit, into the dead centre of the broken off bolt top, through the bolt.
Then, gradually increase the size of the drill bit to slowly widen the hole until you can fit an easyout into it and remove it, or worst case, drill it all out, then clean out the threads.
You'd have to be extremely careful drilling anywhere near the aluminium threads though, otherwise you may have to tap in a new thread, which would not be fun.
You can try dissolving it out with a chemical reaction that dissolves steel, but not aluminum:

Does this really work or just some internet magic..........
Interesting idea, but I think the guy who filmed that video has suffered from too many long dark days in the great white north.
soak for as long as possible and use an impact gun, start slow and gradually increase the power form the gun and once it starts moving dont stop.

im pretty sure those should be studs and not bolts, were the manifolds replaced once already
@Ohthetrees interesting video. I have watched that fellow before deconstructing a jump pack which saved me about 100$ in purchasing one.

@joshAUST good ideas. Interesting you have rust in Australia as well. I have heard welding a nut on from multiple sources and sites. I have used welding to remove rusted bearings and may try "welding a nut on" method of broken stud removal at some point

Steel in aluminum corrosion is a concern here as I have had some experience with this.
broken valve cover bolts

@bigredmachine good advice I have seen guys do this to remove those ford plugs that break with some luck. I have started using an 18v impact gun more often to remove bolts. Don't think that will cut it here though. Will use bigger gun for this application. They are studs. I have all parts to replace just doing my research first.
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There is no easy method for this. Best is the soaking. Always use never-seize when assembling 2 different types of metal.
I subscribe to that guy’s channel (Ave) and he is legit and has many hilarious and useful videos. But he is a bit of a jokster, so it did cross my mind that he was yanking our chains. But I found this which seems to corroborate:

How to dissolve steel without affecting aluminium alloy

It’s cheap, and doesn’t seem like you could hurt anything, so next time I break a bolt off in aluminum I know what I’ll be trying.

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