Stuck Steering Knuckle bolt

I’m trying to replace the CV axle on my wife’s 2006 Chevy Malibu, and the project is frozen in its track by a seized bolt.

Specifically, the top bolt of the two bolts that hold the steering knuckle to the strut. I got the nuts off the other end of each bolt with a breaker bar no problem. I set a jack under the steering knuckle and raised it a bit to relieve any load on the bolts, and with some PB blaster and a hammer, I got the bottom bolt out.

But this top bolt just will not budge. I’ve drenched the thing in PB and pounded the living hell out of it all to no avail. I don’t have any socket that will fit the bolt head and besides, it’s not really threaded in there. I don’t have an air compressor or impact tools. The only thing I can think to do now is to get a torch and try to heat up the metal around the bolt head to maybe loosen it up some.

One way or the other the bolt has to come out now because I’ve mushroomed the other end of it with the hammer and a nut won’t go back on it. If anyone has any thoughts, I’d love to hear them. Thanks!

I have done a few of those & it has been my experience the suspension needs to hang free to relieve pressure on those bolts . If you have a jack under it I think you are creating pressure against that bolt . I also think that you probably need to get a socket that fits the bolt head & a breaker bar so you can get some torque on it . If you have mushroomed the threaded end much you may have to cut that end of the bolt off to get it to go back through once it’s loosened . Enough heat applied to the knuckle will also probably loosen the bolt .

Thanks. Do you think a small butane torch like the one linked below would put enough heat on the area around the bolt head to get it loose? The steel around the bolt head doesn’t appear very thick, but I’m a novice at all of this.

Release the jack under the knuckle. It is adding pressure to the joint. If you don’t have a wrench to fit the bolt get one. You must cut off the mushroomed end of the bolt and while alternately twisting the bolt clockwise-counterclockwise tap on what’s left of the stub with a brass hammer. If that effort totally fails I suggest that you remove the knuckle and strut assemly and work on it on a bench where you can cut the bolt head off and pry the strut off the knuckle, install the knuckle in a good vice and heat the knuckle along the bolt hole while tapping alternately from side to side.

I don’t think you will be able to turn that bolt with a wrench, the bolts are splined near the head so they don’t need to be held with a wrench during assembly.

Heat the knuckle area around the bolt and drive the bolt out.

@Nevada_545 Since you mentioned the splined bolts it jogged my memory & I believe you’re right at least on some vehicles . A Saturn I had apart was but the Subaru I was just working on wasn’t , at least on the rear struts it wasn’t .

Try hitting the threaded end of the bolt sideways in every direction you can. Count to 50 in each direction. Keep this up for an hour. (Easy for me to say.)

That little torch won’t work. Doesn’t put out enough heat.

You want a propane torch with a manual control valve so you can light the torch, and position it where the flame heats up the threaded end of the bolt and walk away and do something else.

It may take up to an hour of the torch being applied before it loosens the bolt.

Home improvement stores sell these as a kit.

This will heat the bolt up faster because there’s less mass in the bolt than the surrounding mass of the other components. Then when the bolt cools back down it should break the bond between the bolt and the steering knuckle.

This is what I use to do before I got my oxy/acetylene outfit.


...light the torch, and position it where the flame heats up the threaded end of the bolt and walk away and do something else.

I wouldn’t walk away from a lighted torch.

Then you haven’t multi-tasked when working on vehicles.


Bought a propane torch. This far, SuperBolt has laughed at my torch’s impotent rage. Gonna try Tester’s idea.

I think I can see the splines Nevada mentions on the other bolt that has already been driven out a bit. I think heat and some patience will probably do the job. After heating the bolt, you might have to knock on it both ways, from the top and finally from the bottom. I’d put a block of wood on the underside probably to avoid or minimize mushrooming the end of the bolt.

Then you haven't multi-tasked when working on vehicles.

Nothing to do with multitasking; everything to do with not catching the car on fire.


When you’ve worked with torches long enough, you can tell when things get too hot.

But here a I am trying to explain to another rookie.


if the knuckle is aluminum I would not heat it.
remove bolts for lower ball joint, tie rod, axle etc. and remove nuts for top of strut and remove the strut as an assembly.

after that if you need to wave a white flag a parts store might be able to press the bolt out.

Do not use hardware fasteners/bolts for reassembly. Use automotive bolts. There is a difference.

That Knuckle does look like aluminum. Even if was case iron I wouldn’t leave a torch unattended on that suspension bolt for any length of time. Shock absorbers/struts are sometimes pressurized.

Be careful with your torch, you don’t want to heat up the strut itself, it contains oil under pressure.

It’s a bit late for this, considering that you say you’ve mushroomed the strut bolt. But there’s no reason to remove those bolts to replace the axle. Separate the lower ball joint from the steering knuckle next time.

Re: Preventing mushrooming of bolts when pounding on them.

When I’ve had to pound on bolts to drive them out I put two or three nuts locked together, right at the end, with the last nut extending out past the end of the bolt a little. The worst that happens this way usually is that last nut gets deformed a little.


That’s a trick my old man showed me years ago!


It took me three and a half hours of torching, oiling, and pounding, but SuperBolt is OUT.

I’m beat. I think I’ll leave the rest of this job (I.e., discovering the next intractable rusted and stuck component) for tomorrow.