Steel (ferrous metals) and aluminum alloys that include pot metal (an alloy of any metal scrap found on the floor of the machine shop and swept up and thrown into the recycle pot) will chemically weld themselves together in the presence of moisture and any electrical charge. Once they have seized solid there isn't any chemical solvent or mechanical force that will separate them.
I had a junkyard 350 out of a pick-up that had been left out in the weather that I was trying to rebuild and the distributor had seized solid in the block. I put a twenty five ton hoist on one end and chained the block to the floor. Result was with enough force I pulled the distributor apart where the top came off the shaft pulling the steel shaft out of the lower portion (after shearing the distributor gear roll pin). I recycled as scrap metal to China a cast iron Q-jet manifold with an aluminum distributor housing welded to it. I then had to machine the lower stub out of the four bolt block by placing the block in a home made fixture in a vertical mill (turns out it wasn't worth the expense).
Getting even further off topic: I could chain it to the floor because while the floor was being poured I had placed two steel plates with a U-bolt off of one of my old Camaro's attached to it In the reinforcing steel wires. Prior to this I had found having an immovable point handy, as I often used an early Ford banjo style axle tube in another shop floor I had poured as a vice stand to pull against while I worked by myself late at night.
I often wished that I had had another anchor point, and came up with the U-bolt idea for my new (now old shop that I have since sold) to give me two points eight feet apart to pull against, or to tie down cars while working on springs, or what ever. I just wish I could have found another old Ford axle, but they aren't as common as the used to be when I was younger, so I welded up another steel stand out of a piece of steel pipe with a big base for my next bench vice to sit on and made another for a big bench top grinder, or chop saw to sit on; but it required unbolting and changing out the tools. (If I ever pour another shop floor I will use a receiver hitch plate held in place by a pin instead of welding the top solid to the stand so the pipe will have to be a thick wall two by two, to make the top interchangeable for a vice, saw grinder, or any bench top tool that I don't want wandering off while I work with it).
In the case of your junkyard find take it back and they will throw it in the scrap metal pile to make a new fender or floor pan for a future project for someone. Copper and aluminum metal in steel however contaminates the melt; and in the United states it wouldn't be allowed to happen. But such is not the case in China, were they have no rules except to maximize profit.
The other issue you will have with a two speed or pulse wiper is how are you going to control it? Your wiper switch has on and off position, but no low or high speed, nor does it support a intermittent wiper operation. You will need a matching switch to control the wiper motor, when you buy another wiper motor. They all interchange with one another, as GM only made two wiper motors from the beginning of time. These wiper motors all have the same bolt pattern to mount them to the firewall and use the same size shaft to bolt on the actuating arm. They where all initially a round motor variant but have been replaced with the square motor style that also incorporates the fluid washer feature.
I have seen advertised pulse wiper dash mounted wiper switches that controlled a pulse type intermittent wiper motor with a push to activate the fluid washer. But the universal switch wiper knob universally doesn't fit any car's interior, and they where large by comparison to your car's knob. The other option would be to take a modern tilt steering column with locking steering wheel and column mounted ignition key and adapt it to fit in your car.
Last edited by Big Dave; 04-06-2014 at 09:07 AM.
Reason: wrote this half asleep