Master cylinder replacement?

Hi,

Are the rear brake rotors rusted? That would indicate the pads aren't making contact. As far as the master cylinder, if it wasn't replaced, bleeding shouldn't be an issue. There is a primary and secondary piston. Has the master cylinder been replaced?

Here are the directions for bleeding the master cylinder. Note that the directions show both in vehicle and out of vehicle bleeding. The attached pics correlate with the directions.

____________________________________________

2000 Ford Mustang V6-3.8L VIN 4
Master Cylinder Priming - In-Vehicle or Bench
Vehicle Brakes and Traction Control Hydraulic System Brake Bleeding Service and Repair Procedures Master Cylinder Priming - In-Vehicle or Bench
MASTER CYLINDER PRIMING - IN-VEHICLE OR BENCH
Special Tools

pic 1

WARNING: Brake fluid contains polyglycol ethers and polyglycols. Avoid contact with eyes. Wash hands thoroughly after handling. If brake fluid contacts eyes, flush eyes with running water for 15 minutes. Get medical attention if irritation persists. If taken internally, drink water and induce vomiting. Get medical attention immediately.

CAUTION: Do not allow the brake master cylinder reservoir to run dry during the bleeding operation. Keep the brake master cylinder reservoir filled with the specified brake fluid. Never reuse the brake fluid that has been drained from the hydraulic system.

CAUTION: Brake fluid is harmful to painted and plastic surfaces. If brake fluid is spilled onto a painted or plastic surface, immediately wash it with water.

Note: When any part of the hydraulic system has been disconnected for repair or installation of new components, air can enter the system and cause spongy brake pedal action. This requires bleeding of the hydraulic system after it has been correctly connected. The hydraulic system can be bled manually or with pressure bleeding equipment.

Note: When a new brake master cylinder has been installed or the system has been emptied, or partially emptied, it should be primed to prevent air from entering the system.

Pic 2

1. For in-vehicle priming, disconnect the brake lines.

Pic 3

2. For bench priming, mount the brake master cylinder in a vise.

Pic 4

3. Install short brake tubes with the ends submerged in the brake master cylinder reservoir, and fill the brake master cylinder reservoir with High Performance DOT 3 Brake Fluid C6AZ-19542-AB or equivalent DOT 3 fluid meeting Ford specification ESA-M6C25-A.
4. Have an assistant pump the brake pedal, or slowly depress the primary piston until clear fluid flows from both brake tubes, without air bubbles.
5. If the brake master cylinder has been primed at the bench, install it in the vehicle.

Pic 5

6. Remove the short brake tubes, and install the brake outlet tubes.
7. Bleed each brake tube at the brake master cylinder as follows:
1 Have an assistant pump the brake pedal, and then hold firm pressure on the brake pedal.
2 Loosen the rear most brake tube fittings until a stream of brake fluid comes out. While the assistant maintains pressure on the brake pedal, tighten the brake tube fitting.
3 Repeat this operation until clear, bubble-free fluid comes out.
4 Refill the brake master cylinder reservoir as necessary. Repeat the bleeding operation at the front brake tube.

____________________________________

Let me know if this helps or if you have other questions.

Take care and God Bless,

Joe

You don't have to bleed anything unless you opened the system so air can get in. Standard procedure is to never top off the brake fluid during other routine services such as oil changes. The level in the reservoir will drop as the pad linings are used up. The pistons work their way out of the caliper housings to self-adjust. Later, those pistons have to be pried back in to make room for the new, thicker pads. Doing that pushes brake fluid back up into the reservoir, at which time it will be full again. If someone filled it previously, the brake fluid will overflow and make a mess.

If a brake pad is catching on a rotor, it suggests that rotor is worn way beyond the published legal limit. Ford uses relatively soft metal for their rotors so they're quieter, but that means owners often don't hear the grinding sounds when the linings are worn off the pads. By the time you hear that grinding, the rotors are worn too thin to be legally machined. When a rotor wears so far that one of the plates is totally gone and the cooling fins are exposed, that is when a pad can get caught on it.

If you read somewhere about bleeding at two wheels, that is commonly the procedure when you have to bleed an anti-lock brake hydraulic controller. No air will get stuck in it if no air is pushed down from the master cylinder. In fact, there is an easy way to avoid having to bleed at the wheels when you replace a master cylinder.

If you do push air down the lines in an attempt to bleed at the wheels, there's usually two chambers in the ABS hydraulic controller where that air gets trapped. To get that air out, you need a scanner to command the computer to open two valves, then the scanner will instruct you to open those two bleeder screws at the right time. That gives the released air a place to flow to.

You might find more dandy information in this article:

https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system

Hi,

If nothing was opened, it doesn't sound like bleeding is needed. Can you take a pic of the rear brake rotors so I can see them? I need to determine if they are not working. Has anything been done to the brakes at this point?

Let me know.

Joe