Bolt removal

[JimR]

Here's my experience from removing the exhaust manifold on my 1994 Ford F250. The nuts are supposed to 9/16 or 14mm socket size. They were so rusted that most of them had to be removed using a 1/2 inch socket pounded over the rusted nut. The last one took a 7/16 socket to remove it. Every one, 8 in all, came out without a problem as the holes are blind on the head. Worst case scenario is that you will need to drill and tap a few if they break off. You can split the nuts with a very sharp chisel and hammer. Remove the manifold and use an external stud extractor to remove the studs.

 

[normde2001]

"In the past I have sprayed with some type of liqid wrench, tap on the end of the bolt with a hammer, and hope for the best."

What didn't you like about "Liquid Wrench"? It works as good as "P B Blaster".

 

[mrutkaus]

if it's really important soak it in aerokroil or pb blaster or whatever (probably doesn't make a difference) for a couple of weeks or a month. use some sort of a clay dam etc. spray it couple times a day. take your time.

this was successful with old mercedes manifold bolts broken off. i even rigged a tube to go down to the area i wanted to soak so i could just go over and spray into the tube.

mike

 

[dbdartman]

If you do break a stud or bolt, it would be well worth your time to find a set of left-hand drill bits! Although I've only used them 3 or 4 times, they've never failed to remove the stud. Not only do you get the "differential heating" but the counter-clockwise turn helps pull the broken stud/bolt out instead of the standard bit wanting to seat the stud/bolt further into the threaded hole. My experience with the LH bits is that they typically get about 80% through the stud then spins them out slick as can be!

 

[Trainer]

Cranked the engine and let it warm. Killed the engine and sprayed the nuts with PB Blaster. Let the engine cool and sprayed. Let sit for about 4 hours and removed the nuts. Not a problem. Wondering if spraying while the engine was warm and letting it cool with the PB on it helped pull the PB into the threads. Just curious. Wasn't concerned about damaging the manifold since I was replacing it. All went well.

 

[Dusty]

I used to have a hard time with the studs that came off the back end of the manifold where the exhaust pipe would attach. I learned about a good trick that works for me every time. I heat the manifold with the acetylene/oxygen torch till it is cherry red. Then I grab it with a pair of vice grips that I had put in the freezer the night before. Once the ice cold vice grips lock down on the stud, the stud cools and you can rock it a few times and then just spin it right out. Wearing gloves helps to keep your hands from getting frost bite. When I reassemble, I use stainless steel studs with anti seize compound and brass nuts, double nutted. Dusty

 

[zeuspaul]

I worked in a muffler shop for five years. We removed steel studs and nuts where the exhaust pipe meets the manifold with cherry red heat as Dusty indicates on a regular basis. However there was never a need to use cold vice grips. The heat was sufficient.

Broken studs were removed by welding on an extension and then heating the cast iron manifold till it was cherry red.

I do not recommend stainless studs. They are very difficult to remove when they break and they break easier than a HIGH GRADE of steel. Older Cadilacs had stainless studs and they were always a problem. They are hard to weld to, hard to drill and hard to burn. Burning steel out of cast iron is a quick way to remove a broken stud but it requires skill...you can ruin your manifold if you don't do it right.

Also I don't recommend brass nuts on steel....MAYBE on stainless if you have to use stainless (I never would in a cast iron manifold.) If the stud is subject to rust or crud on the threads the nut strips as you try to remove it. Brass nuts can be used when existing nuts are in poor condition.

Double nutting is usefull in protecting outer threads and facilitates later removal.

I would use a high grade of steel in the block and manifold.

Zeuspaul

 

[Soundguy]

Using brass nuts to hold a manifold on is a very common practice. The nuts strip out before your block does.

soundguy

 

[Dusty]

I don't ever use stainless nuts on stainless bolts, because I have had problems in the past with galling and difficulty removing. I do use a very high temperature anti seize and that has worked well. Problem is that steel rusts when it is always being heated and cooled and exposed to water vapor. Every application requires a different technique to accomplish the job with the least amount of effort. I also am careful when installing stainless studs. You are correct, once they break they are more difficult to remove. Dusty

 

[Captinjack]

I buy my Kroil directly from the factory in gallon cans and then use a small application device (hypodermic needle) to put a small amount of liquid on the nut. This has to be repeated over a week on the truly rusted bolts or nuts. They can then be easily removed.

I usually use a 3/8" air wrench set on low pressure to remove the nuts as the vibration really improves the effectiveness.

A friend has a Model A that had a stuck engine and after weeks of other treatments he was resigned to cutting everything off to disassemble. Two weeks with Kroil and everything came apart including the stuck pistons.