Best way to start on rusted exhaust nuts (wrench vs impact) without destroying it?

TerryMason

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I need to take apart a section of exhaust on my mom's Ford Escape - it's only four nuts, and they don't look too bad. I've been hitting them with PB Blaster for a day or two, and I'm about to the point where I want to take them apart.

I've got a hefty 1/2 inch Dewalt impact that would likely make short work of this, but I was wondering if it's better to start with a standard socket wrench before going straight to the impact? My goal would be to not break the studs off the exhaust.

I've got a torch that I use for plumbing, but it's not something that I often use on the car. I would likely only use this as a last resort.

My current plan of attack is to start with a socket wrench, if needed move to a breaker bar, and finally impact gun.
 

Are these the bolts for the catalytic convertor? If so, how old is the car?
 
i have found the best way to loosen stuff like that is with the longest breaker bar i can find so i can apply smooth easy torque. turn it a little and then turn it back the other direction to clear the threads. than turn it some more and go backwards to clear the threads. just keep doing it till it comes off
 
Are these the bolts for the catalytic convertor? If so, how old is the car?
No, these are on a Y pipe. Only thing that connects into it is an O2 sensor. I need to remove this portion of the pipe in order to drop the oil pan.
Car is a 2009 Ford Escape.
 

i have found the best way to loosen stuff like that is with the longest breaker bar i can find so i can apply smooth easy torque. turn it a little and then turn it back the other direction to clear the threads. than turn it some more and go backwards to clear the threads. just keep doing it till it comes off
This is what I'm thinking, but I read on another form that you should start with an impact because the vibration can help loosen things. I'm tempted to use your method though.
 
Soak and heat. Soak and heat. Then like above get it to budge with torque. Back and forth. Soak and heat.


Never look down on anyone unless you are helping them up - Jesse Jackson
 

I'm going to say that I had partial success getting these nuts off. Right off the bat. Things were weird because one nut appeared to be a different size than the other. It turns out they were just so rusted that they had disintegrated. When I put my six-point socket on the nut rounded off with light to moderate force on a socket wrench.

PXL_20240919_184615706.jpg


What eventually saved the day were these nut extractors. I picked them up at advance Auto parts for $40



PXL_20240919_195450287.jpg


They took the nuts off like butter. I had to use a 7/16 on one night and a 3/8 on another, but they made it easy to turn off the nuts with just a socket wrench.

I got into trouble with the fourth and last nut, when the bolt sheared off


PXL_20240921_130208522.jpg


Here's what everything look like after I took it off

PXL_20240919_215113587.MP.jpg


The exhaust stud that's left behind is of the press-in variety. I bought a map gas torch from home Depot to try to heat it. I sprayed it with PB blaster heated it as hot as I could get it and beat on the stud with an air hammer but it wouldn't budge. I tried this process about four times until I was defeated.

I put it back together for now and it's definitely louder than I'd like. I'm on the fence if I should just pay a local mechanic to fix this broken stud.




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While map is better than propane I'm thinking you need a real torch. How red did your map torch get the stud?
 
The stud began to glow a little bit, but not very much. The exhaust flange didn't glow at all.
The youtube videos I've watched have the whole exhaust flange glowing bright red. My plumbers torch from Home Depot couldn't do that.
 

About 50 yrs ago I rented a small set of torches from a rental place. I don't know if that can still be done or what the cost might be.
 
They should be two different sizes. Right is bigger.


Balljoint extractor


Never look down on anyone unless you are helping them up - Jesse Jackson
 
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Soak and heat. Soak and heat. Then like above get it to budge with torque. Back and forth. Soak and heat.

About this - I've got cans of both PB Blaster and Seafoam Deep Creep, and both of them have "warning flammable" on the back. I sprayed the nuts / stud several times, but never when it's hot.

Are people getting these bolts red hot, then spraying Blaster on them, or waiting for everything to cool first? I was worried I'd burn the car down.
 
I've sprayed PB Blaster on red hot bolts before but prepared to put the flame out if needed. Generally the flame isn't that big of a deal to put out. I'm not convinced that spraying the PB Blaster on red hot bolts/nuts helps a lot. IMO heat does more than anything.
 
Penetrating oil helps break down rust also I just spraying the bolts, cools it quicker than the flange and allows separation.


Never look down on anyone unless you are helping them up - Jesse Jackson
 
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