Thanks in advance.
Kroil, or maybe Ballistol. I’ve used both with success. The smell of Ballistol attracts women, too. They come in the room and say “what the hell is that smell?”
Try using a manual impact driver. If you haven’t seen one, it’s a reversible tool that you hit with a hammer. The force of the blow drives the bit into the screw and at the same time it turns the bit to remove the frozen screw. You can pick one up at Autozone for about $12.00.
Steel screws in aluminum is a good recipe for sacrificial or cathode / anode corrosion. The aluminum is sacrificial to the steel and will oxidize to protect the steel from further corrosion. This may not turn out well.
Try the Kroil or liquid wrench or PB Blaster and gentle patience. It is likely the threads in the aluminum will come out with the screws though and you’ll have to drill and tap new threads or use a helicoil to keep the same thread size.
They have started using aluminum on some garden hose fittings. Given just a little time those suckers will weld in place with corrosion.
I just pulled some cap screws off the tractor this afternoon to find corrosion in steel or steel. Always assemble with thread lube if you expect to take things apart.
Another vote for Kroil. I find that if Kroil won’t get something unstuck, the blue “wrench” is the only remaining option. Let it sit a while and give the fastener a gentle tap with something before you try to budge it. Steady pressure seems to get it moving eventually.
My tried and true method for removing stubborn set screws...
After all the other methods (heat and penetrating oil)
Buy a torx bit, they are also called star bits. You should be able to find them at the hardware store but will most likely come with a pack. Hammer the bit in to, what’s left of, the corners. Use a 1/4 socket and you can get a lot of torque that way. The torx bit cuts in to the metal and will sometimes work. After everything else... Time to break out the drill bits and easy outs. If you still can EZ out them drill them out all the way to the threads, chase the threads, or use helicoils if needed.
Burn em out
Good luck, and when you reassemble since it is aluminum, use Permatex Anti-Seize Lubricant or equivalent.
Regular Coca-Cola is better than WD-40 for freeing rusted bolts. Construct a simple dam around the bolt head (plumber putty or caulk),pour full of Coca-Cola and allow to work. Mix the remainder of your Coke with Bourbon and enjoy a few drinks while you wait.
Wack them just almost straight on with a flat punch and hammer without damaging the allen hole. Then they will come loose.
PB Blaster. Apply and
let it soak for a few
minutes.
You are encountering
a dissimilar metal
corrosion condition.
I have used this stuff on
very rusty hardware.
Left handed drill bits and plenty of knocker loose.
Aerokroil and PB blaster are the two best I believe.
Propane torch to heat the block some may help. Aluminum dissapates heat badly and it does not melt slowly, it just collapses quickly if you overheat it.
About my above post. Get a left handed drill bit. Get a small metal punch and grind a fine point and tap a small indention.
Use the left handed drill bit in a cordless drill. Drill counter clockwise.
Soak it for a few minutes beforehand in knocker loose.
Do these screws hold the block onto another one of steel or aluminum?
Warm them up with a torch, not to hot, just warm enough to expand a little bit, then cool them off with some diesel oil.
They may have Loctite on them. I believe Loctite makes a solvent
Tighten slightly and then let it sit with oil. Try again. heat never worked well for me, probably never did it right.
All you really have to do is budge the threads loose a touch, hence the tighten first. Waiting lets the oil get into the loosened threads.