I have never heard of such a thing and I wouldn't recommend it. I have heard of old timers putting a teaspoon of motor oil in their tank when they filled it to preserve valves. I wouldn't recommend that either. If your motor is seized ( you said locked ) this wouldn't help. If your motor is seized you can't turn it by putting a wrench on your crankshaft bolt. This usually means something is wrong in the motor itselfand adding something to your fuel will be fruitless.
If the engine has been sitting for years and is just locked due to non-use, remove all spark plugs and pour 1/2 cup of kerosene in each cylinder. Wait 48 hours see if you can turn it over with a socket and ratchet at the crankshaft. If you can, then change the oil/filter, put the spark plugs back in and see if it will turn over.
If your motor has interference heads do not try to start it with out finding out if it is out of time. If one of these motors is out of time you won't be able to turn it because a piston(s) is touching one of the open valves. Starting it could shoot one of those valves through your valve cover or damage ( or break ) a rod.
If the vehicle has been sitting for years ( as above ) the timing belt is much more prone to breaking. The polymer in the belt conforms to the shape of the pulleys and becomes brittle. Most recommend 4 years or a certain number of miles ( ie 60K for BMW). Consider this if your motor has interference heads; even if it is in time and has been sitting you should probably change the timing belt.
The 1981 Chevy Cheyenne brake fluid tank can be found attached to the firewall in the engine compartment. The brake fluid tank will be on the drivers side of the firewall.
It goes into the brake fluid resevoir, a tank located in the engine compartment. Specific location will vary depending on the engine you have.
close to the white water tank
There are 3, actually. Brake fluid, power steering fluid, and engine coolant expansion tank.
THe fluid will need flushed and changed.
NOTHING
The brake fluid reservoir is located under the hood, on the firewall, drivers side.
Open hood, look at the rear right of the engine compartment. You'll see a coolant tank. Near the tank you'll see the brake master cylinder with the plastic reservoir attached directly on top.
master cylinder holds the brake fluid,open it up and add brake fluid to the tank. Make sure you use NEW brake fluid and one that has not been laying around in someones trunk. Remember this what stops your car. Contaminated fluid is very bad for you and your brakes. Usually the master cylinder tank is white in color and sits on the master cylinder itself.
your gas tank
The best answer is to ask your local Toyota dealer. The alternative answer would be to screw the cap off your tank in the engine bay that says brake fluid. The fluid on the stick should be a clear light brown. When you touch it the fluid should not be slippery, greasy, or discolored. If there is any sediment in there then change it right away and make sure to clean out the fluid reservoir. Also change your brake fluid every two years and flush out the brake lines for superior maintenance.
it is DOT 4 brake fluid which is filled through the master cylender for the brakes...it does not have a separate fluid tank.