when the brake fluid is dirty it should be a clear watery color it will be almost brown when its dirty
Brake fluid can corrode your water pump. If you didn't start the engine after installing the brake fluid, then pump the reservoir empty, flush it with water and refill it with proper coolant. If you DID start it, you need to flush the whole cooling system.
If you're only changing the pads, no. You only need to bleed if the hydraulic system was opened or if you wish to flush/change the brake fluid.
What disc's are you referring too? If you are referring to Brake disc's, then it is probably the caliber and your brake system is contaminated with moisture. You need to flush the brake system, replace all brake fluid, and replace any defective parts. Any calibers that are sticking need to be replaced. It can also be the slide pins on the disc brakes that are corroded and need replacing. A complete brake system service that is done correctly will repair this problem.
You need to completely flush the system of all contaminated brake fluid. As this is a very serious and possibly dangerous situation I recommend you take this car to a professional and have the system completely flushed and refilled with fresh fluid.
Calibers are sticking. You will need to replace the calibers that are sticking and flush all the old brake fluid out of the system then replace it with fresh fluid.
After having problems with seizing wheel cylinders and other brake problems due to moisture in the hydroscopic brake fluid, I started flush clean fluid through the brake systems of my vehicles every 2 years... Have not had a single corrosion (or any brake problem for that matter) since...
The only reason to flush the ac system is if you had a compressor burn out. if this did not happen you just need to have the system recharged. you might have air the the system pull a vaccum on the system this should remove the air and the moisture. ******************************************************************* If you replace the compressor you should replace the drier and expansion valve and flush the system. To flush it you need a flush solution and clean dry compressed air. Put the solution in and force it out with the air one line at a time until the flush comes out clean. Install the new parts with the proper amount of oil and recharge the system.
If there is metal chips and trash from the old compressor in the system, yes you need to flush the system. Any trash left in the system will shorten the life of the new pump.
You can go get it done at a shop or you an even do it yourself. But in order to do it yourself you need to know what you are doing so you don't mess up your car & mess up your break fluids.
Then you need to bleed the brake system to remove the air.
If you mean low of brake fluid, the answer is no. When a caliber locks up it is usually caused by contamination of moisture in the brake fluid. This causes the caliber to rust and then it will lock up. You are more than likely going to have to replace both front calipers. You also need to flush your brake system and put in fresh brake fluid.
Air in the brake system. You need to bleed the air out of the system.