Yesterday I went out to replace a cracked exhaust manifold on the passenger side of the 8BA in my '37 1 1/2 ton. I have rebuilt quite a few of these things, and have always had really good luck removing the manifold bolts. Until yesterday.... Got the exhaust y pipe off both sides and tested the manifold bolts. Only one was easy. The rest are really tough. If I were to break one off flush, it would be a total pita to drill out as I'm sure you know. I heated the stuck ones cherry red and let them cool and soaked them with PB etc. I finally chickened out and put the y pipe back on and decided a crack was better than the alternative. Afterwards I've been thinking about some ideas.. I just can't let that manifold win. I could torch off the bolt heads or sawzall of them off. Break up the junk manifold into pieces or whatever to get at the bolts. I feel if I could heat and soak the shank of the bolt where it enters the block, I could get good access and purchase with a nice sharp pair of vice grips. Can someone offer advice from their experience with these bolts. I really don't want to break any off. Signed, Defeated......

 

Have you ever had the bolts out? If it was off at all recently, I'd be more confident you can get them out without any real risk, but if they've been in there for 20+ yrs, your fears are justified.

A couple of tricks; one is to try to tighten them a bit first, by hand, then hit them with an impact gun to remove. Another is to whack them on the head pretty good with a ball peen hammer; it relieves some of the stresses in the threads.

Personally I'd be skeptical that any panther-**** is going to get up in the threads where it will do any good.

If you do break one off, the best bet is to do the trick where you put a washer over the hole and/or remnants, weld the remains to the washer, then a nut to the washer. The heat gets up into the threads really good from the welding and seems to work great. Of course, welding while the engine is in the truck is no treat!

Going back in, Copper Coat seems to prevent future problems pretty well.

 

Na your not defeated, they always freeze cast iron to the bolt. We do
this all the time I get the ones out, dont even mess with one that do
not exactly as you think we wizz off the head heat manifold. 98% it
will come out with a vise grip. Be greatfull its a flathead just try this on
mordern junks. On a late F150, one week, for one bolt alum head cast
manifold steel metric bolt what a combo, no room everthings plastic
(for the torch) ended up with a $35 drill bit buggered up hole so we
drilled and tapped for the next size and put a stud.

 

Heat can help a lot for these issues, but you don't want to heat the bolt. Heat the block where the bolt threads in at and heat it as fast as possible. By this I mean use a real torch and not a little propane thing. The heat will cause the iron block to expand and let go of the threads of the cooler bolt. If you heat the bolt itself, it will expand and wedge itself even tighter in the block.

 

Thanks for the replies. The truck was in a barn for 26 years before I bought it 4 years ago, so we're looking at at least 30 years. I've got oxy-acetylene and a welder, so I can do this stuff. I've done the washer and nut trick on a head bolt, but upside down in that space, I agree no fun at all. Like I said, I've pulled a lot of these manifolds, but most often they are from an engine sitting on the shop floor and usually from a engine found to be cracked internally, so I just bust out the breaker bar and crank them out. I can't recall breaking one in that situation, but that's normal when it doesn't matter. The manifold is broken in half and I hate exhaust leaks ( pet peeve) so I will attack it some day this week after work. If I decide to remove most of the manifold for access to the bottom bolts, should I bust it off with a ball peen or saw it apart with the sawzall? Could the matal grit get upwards into the valves?

 

Take a look at this, fairly new in USA, been in Euro for awhile

When I was in USAF we used liquid Oxy to freeze stuck stuff

 

I'd cut the heads off the bolts, that manifold cracked from years of thermal stresses, not because it's brittle as glass.

One trick Dick (4TL8Ford) taught us here is heating up the stud that remains and putting paraffin wax on the threads -- it will suck in along the threads.

 

Thanks for the tips. I just might have to start in tonight, then I'll be able to sleep better. I'm sure you know what I mean......That shiny gasket at the pipe flange is a 'Remflex' graphite gasket. They squish down to conform to any imperfections and are good to a million degrees or something. I use them on all my exhaust work these days.

 

Just grind along that crack to get it clean and JB Weld it!

I can definitly understand your concern of breaking that bolt off in there.
Good luck with which ever way gets it out of there.

Josh

 

Does JB Weld really work at those temps? I have used marine-tex and jb and others on water leaks and all kinds of stuff, but direct heat from the exhaust? I used to use those 'muffler cement' products back when I was a kid in the 60's, but with the pressure blasting out, they never last. It's 4:45, work is over. I'm goin' in..........

 

Gonna be sleeping like a baby tonight.... Thanks for the help.

 

Good job! Do you have a replacement manifold?

 

I have a few of them from all those cracked blocks I've come across over the years. It goes on tomorrow after work! Thanks again. zzzzzzzzzzzzzzzzzz