Dreaded exhaust manifold bolts

[Drakeule]

All:

 

I am considering attempting to install new exhaust gaskets and possibly replacing the exhaust manifolds themselves(as I know the center section has cracks.)

I have started to bath all the bolts with Kroil, which I understand is the best thing to use.

 

What are thoughts on doing this job; I just want to get a feel for it before really attempting it.

 

Thanks in advance,

C Drake, Potomac, Md.

[JFranklin]

I would use the penetrant for about a week or more before trying to remove the nuts, but you can test after a few days to see if things will move. 

[EmTee]

You could also try heat and then apply the penetrating oil.  Key will be give it time and more cycles the better.

[Mark Shaw]

Penetrating Oils

 

Machinist's Workshop Magazine (March/April or May/June, 2007) actually tested penetrants for break out torque on rusted nuts. They arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a "scientifically rusted" environment.

*Penetrating oil ..... Average load*

None ..................... 516 pounds
WD-40 .................. 238 pounds
PB Blaster ............. 214 pounds
Liquid Wrench ..... 127 pounds
Kano Kroil ............ 106 pounds
ATF-Acetone mix....53 pounds

The ATF-Acetone mix was a "home brew" mix of 50 - 50 automatic transmission fluid and acetone. Note the "home brew" was better than any commercial product in this one particular test. Our local machinist group mixed up a batch, and we all now use it with equally good results. Note also that "Liquid Wrench" is about as good as "Kroil" for about 20% of the price.

[DonMicheletti]

I have had amzing results with the ATF / Acetone mix.

I have disassembled rusted parts that I thought were hopeless. Beats any commercial product I have used and I have bee "playing" with old cars for near 60 years

[1937 Buick 66C]

Another thing that is helpful, if you can do so easily, is to apply the ATF / Acetone mixture when the seized parts are warm (not hot, as the penetrant will flash off prematurely).  As the part cools, the penetrant will be be drawn into the threads.  As EmTee suggested above, the more cycles the better.  If the car is running, you could start the engine to warm up the manifold, then apply the ATF / Acetone penetrant and allow to cool.

[Morgan Wright]

I don't know what year your car is, or how original it is. My 1940 had brass exhaust manifold nuts on steel studs, as well as the connection between the manifold and the exhaust pipe, had brass on steel. The brass nuts are extremely soft and you will round them if you use the wrong wrench. I don't know if they were original, the car had the engine replaced in the 1950's so who knows. My 1917 has the original carbon steel nuts and they came right off without even using penetrating oil.

[Drakeule]

All:

 

After liberal application of Kroil over the last 3 weeks, I was able to loosen all 10 bolts with just a little help from a cheater bar on # 9 (second from rear.) I will now replace the center exhaust section (as it has several cracks.); I will inspect the front and rear sections for cracks, and replace if needed.

 

Brass gaskets best for reassembly? Also, any other tips would be greatly appreciated!

 

VR,

CD, Potomac, Md. 

[JFranklin]

Penetrant oil is a great thing. I had to remove a tractor manifold and most of the nuts could only be removed with an open end wrench. I soaked it for a few weeks and every one of them moved.

[EmTee]

12 hours ago, Drakeule said:

Brass gaskets best for reassembly? Also, any other tips would be greatly appreciated!

http://catalog.remflex.com/BUICK_Header_Exhaust_Manifold_Gasket_p/13-009.htm

 

[Drakeule]

EmTee/all:

 

Remflex good stuff? Better than copper?

[Aaron65]

Absolutely.  I've been using Remflex on my '53 Buick with a 263 and they last years longer than anything else I've tried.