exhaust bolts

[fishon79]

having trouble with removing the exhaust bolts to a 4.0 at heads. have been using penetrating oil and striking them hasnt helped. anyoneknow about using heat where and how hot any help is appreceated

 

[AllanD]

Don't heat the bolts heat the exhaust port flange where they screw in.

But I'll warn you with a tight fitting socket and an impact gun you can usually get the bottom three out on each side.

I've done that job dozens of times and if I get ONE of the upers out I consider myself lucky.

My best ever is getting two of the uppers out (I still snapped a lower)
And I broke all six on the other side of the engine.

Frankly and bluntly when doing that job I expect to have to drill and
heli-coil all six bolt holes before reassembling the exhaust, UNLESS
I've already been there and heli-coiled the holes in which case they'll
come out almost effortlessly.

AD

 

[countryboy]

nice info allan

 

[Ranger#1]

on my 90 i made all out but one witch was on top aply heat to the threads surounding the bolt

 

[Toms01PSD]

I managed to remove all of mine without breaking a single one. Use lots of pentrating oil and let them soak a little. Use a quality socket and more ass!

 

[AllanD]

One other thing I should note...

When I drill and helicoil the exhaust port flanges on
a 4.0 cylinder head I DO NOT use the original metric
threads.
I rethread and helicoil them for 5/16-18UNC threads
because generally speaking the english bolts are available
in the proper lengths without special ordering them

In this application I prefer Grade 8 bolts because they are hard
even if not necissarily strong, and this inhibits them from
frictionally/vibrationally welding to the 18-8 Stainless steel
material from which the heli-coils are made.

Even so I use the prevailing torque Heli-coils to keep the bolts
from vibrating loose (though compression of my header gaskets
is more of a problem) while they are smeared with never-seeze
to prevent them from corroding in place.

AD

 

[Toms01PSD]

I used the stock size 8mmx1.25. Instead of using the old crap, I got some bolts in that size and just used a hacksaw to cut down what I needed. Worked fine for me...

 

[fireguy12117]

i got all 12 out- when the heads were on the bench. just like was mentioned, i got a tight fitting socket on the bolt, breaker bar, pulled all the slop out everything, then gave a really good solid hard jerk on the bar. once the bolt 'popped' i was able to go the rest of the way with a ratchet and going slow.

seems like more often then not, its almost technique rather then tools or oil that gets things apart.