The manifolds on my '37 Buick are rusty and the bolts holding them together are stuck solid after soaking with penetrating oil for a week. The bolts go deep inside the parts and I it would be hard for the penetrating oil to get far enough inside to attack the threads. Would it hurt to soak the entire unit in used drain oil? I am wondering if the oil will soak into the cast iron and cause a problem. I do want to paint the paint the parts before installing and I'm concern the oil will get into the cast iron and prevent paint from adhering.
short answer is no. it wont hurt your casting drain oil wont do shit tho. try a mix of diesel and transmission fluid.
I restore vintage bicycles and have been using oxilic acid (wood bleach) for cleaning rust off of chrome parts. I'm sure it would the job on your manifolds. Basically, it comes in a crystal form that you mix with water. I've only found the stuff at Ace hardware stores, HD & Lowes don't carry it. As far as removing stuck bolts, soak them with 'Blaster penetrant, you can find it at any good auto parts and I think Wally World carries it too.
pb blaster does not get deep into threads the way that the diesel/trans fluid can, least not in my experiance... not to mention the COST to literally submerge something other than one bolt in the stuff
50/50 ATF and Acetone is about the best creeper around. Soak them for a while and try heating the manifold to red and try backing the studs out. If they snap off you were headed to the machine shop anyway....is your hardware in bad shape??
vinegar loosened some rusty nuts and bolts for me as well as my electrolisis bath id try either before soaking it in old nasty used oil
Hit the top of the bolt head straight on with a drift punch and a big hammer a few times. Real hits, not little girly hits. Then try a wrench on the bolts and watch them back out like they are supposed to.
I've been soaking them in the ATC/Acetone solution for a 3-4 days. I not concerned about the surface rust, I'm going to blast them once I get them apart. My concern is the bolts that hold the intake to the exhaust. They stacked on top of each other and the threads are buried deep inside the bottom manifold. I want to be able to get something to seep deep down inside.
x 2 Submerge in a bucket of feed-grade molasses mix (dilute with water...3-5 parts water for 1 part molasses) for a few days, maybe a couple weeks. Side benefit the manifolds will also come out rust free. Don't do this with anything alumnium, magnesium, brass, etc...just iron and steel.
ATF and Acetone, torch, hammer. If that doesn't work, break them off and drill them out. It's not all that hard if you have a solid place to clamp the manifold. Grind smooth, center punch. Pilot hole. Work up in steps. Maybe with a left hand drill if you have one. Helicoil if necessary.
i would think the rust is at most a 1/2 inch down inside the parts unless you bought these parts out of a salvage yard and they had been siting exposed for years when metal goes through years of heating and cooling cycles they tend to tighten up i think thats what your fighting... not rust but whadaiknow
heres another thought i just enlarged your picture if that is the same intake/exhuast your tryin to get apart are you sure it comes apart? reason im asking is i dont see a dividing line where you have the red dotted lines drawn.... again whadaiknow i dont mess with 6's much
This is how you do it. Give it a try. No heat, no penetrating oil, just a few good hits on the head of the bolt.
I want to be a gentle as possible with this piece because if I break it it's going to be extremely hard to find a replacement. If it was a common piece I'd have had the torch on it in a minute. I've torched broken exhaust manifold bolts out of heads without a sweat. I don't think soaking in molasses will do it, I doubt if it would seep down deep enough to get to the thread. I also don't want to wait a couple of weeks. I hope to have the engine running in the near future. I got this piece off of the original '37 engine, which was in a beat up car that sat outside for unknown years. I bought a '40 engine but I can't use the nicer '40 manifolds on the '37 engine.
here's the rub... you cant have it both ways here. you cannot get them out in a hurry, and have zero worry. no two ways about it.
I didn't expect an overnight solution, but I'd think a week soak should do it. I applied all of the suggestions given, soak the parts for about a week with the ATF/acetone solution, gave all three bolts a couple of good whacks with a center punch and BFH (the one thing I never thought of). Two came out fairly easy, the third I added a little heat and it came out. Now on to the blaster and a new coat of hi-temp paint to make it look pretty.
soaking won't do it by itself, you will no doubt have to use a torch, get it red hot and work the bolt back and forth until you get movement. be patient. lots of heat and it will come out with some effort. i broke a bolt off on my 53 pontiac manifold and my friend got it out this way. use atf/acetone and heat.
you must warm up, and tapping it with a small hammer. heat expands the metal,small proposals to solve. my was also very rusty,(look my profil) And, I also have the inside de-rusted and polished.
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