If you replace brakes on your vehicle and your having trouble bleeding brakes by yourself park your vehicle on steep incline,loosen cap on master cylinder and let sit over rnite with emergency brake on. the next morning slowly pump pedal. tighten cap and there you are the air rose to the top and self bled;

GRAVITY BLEEDING CLUTCH HYDRAULIC CIRCUIT

1. Verify fluid level in brake master cylinder. Top off with DOT 3 brake fluid as necessary. Leave cap off.

2. Raise vehicle on hoist.

3. Remove bleed port protective cap and install suitable size and length of clear hose (4) to monitor and divert fluid into suitable container.

4. Open up the bleed circuit by turning the thumb screw (3) counter clockwise this will start the air purge and fluid fill process.

5. Lower vehicle, but only enough to gain access to and fill the brake master cylinder. NOTE: Do not allow clutch master cylinder to run dry while fluid exits bleed port.

6. Top off brake master cylinder fluid level while air is purged and fluid drains from bleed port. Continue this until no air bubbles are seen and a solid column of fluid exists.

7. Close hydraulic bleed circuit, remove drain hose and replace dust cap on bleed port.

8. From driver's seat, actuate clutch pedal 60-100 times.

9. Apply parking brake. Start engine and verify clutch operation and pedal feel. If pedal feels fine and clutch operates as designed, stop here. If pedal still feels spongy or clutch does not fully disengage, excessive air is still trapped within the system, most likely at the master cylinder.

10. Top off brake master cylinder fluid level with DOT 3 brake fluid as necessary.

POWER BLEEDING CLUTCH HYDRAULIC CIRCUIT

1. Remove reservoir cap and connect bleeder cap to reservoir. NOTE: Use Bleeder Cap/Modified reservoir cap adapter Snap-on #901-059 or equivalent.

2. Connect service filling machine to bleeder cap. NOTE: Use Service Filling Machine/Brake power bleeder Brake power bleeder or equivalent.

3. Service filling machine should be pressurized to at least 2.5 bar (36 PSI).

4. Remove dust cap from bleeder valve and connect the transparent bleeder hose to bleeder valve.

5. Place the other end of hose in the bleeder container to capture the used fluid. The end of the hose MUST be submerged in the DOT 3 brake fluid.

NOTE: Use Bleeder Container To capture hydraulic fluid and Transparent Bleeder Hose To route fluid to container.

6. Turn on the service filling machine.

7. Crack open the bleeder valve (3).

8. Allow fluid to flow out of bleed port until no more air bubbles can be seen in the transparent bleeder hose.

9. Once fluid is free of air bubbles; make 15 quick actuations between clutch pedal stop positions.

10. Close the bleeder valve and disconnect the service filling machine.

11. To remove remaining air, actuate pedal 10 times slowly between pedal stop positions.

12. Check clutch pedal to see if vehicle is properly bled.

13. If vehicle is not properly bled, repeat procedure.

14. Remove bleeder cap from reservoir and replace reservoir cap.

15. Disconnect transparent bleeder hose from bleeder valve and replace dust cap.

Well, if you change a caliper or a brake line the fluid in the master cylinder should remain, even if the fluid leaks out.

However, if you are having trouble bleeding regularly, then use a vacuum pump with a 'can' or use a pressure bleeder (I prefer this method) that costs about $55 or so available on the Internet.

If you use a pressure bleeder, you'll need an extra master cylinder cap that has a hole drilled in it to accomodate the fittings of the pressure bleeder.

I know someone who had a Lincoln Continental that changed a brake line and had trouble bleeding it, and they used a vacuum pump and it bled easily using that method.

Some cars require that when you change the master cylinder, a brake scan tool is required to bleed the master cylinder that has air in it. But, if you did not replace the master cylinder, you should be able to use either the vacuum or pressure method to bleed the brakes easily.

Good luck on this repair.

a Master rates about a 5 out of 10 with 10 being the hardest

you may find the hardest part is the actual bench bleeding of the master
and/or
the replacement of the reservoir

These are the instructions from my service manual, but I do not remove the fluid prior to service steps 2-6

1. Disconnect battery ground cable. Disconnect electrical connector from filler cap.
2. Remove fluid reservoir filler cap.
3. Raise and support vehicle.
4. Remove front wheels.
5. Remove dust cap and loosen bleed nipple. Connect a bleed tube to bleed nipple and into a suitable container.
6. Pump brake pedal until all fluid is expelled. Tighten bleed nipple.
7. Lower vehicle. Install brake fluid reservoir cap. Remove air cleaner and air cleaner outlet tube.
8. Disconnect central electrical box electrical connector.
9. Remove central electrical box retaining screw.
10. Remove central electrical box and relocate to air cleaner area.
11. Disconnect brake fluid feed tube. Disconnect brake lines.
12. On models with anti-lock brakes, disconnect brake lines from Hydraulic Control Unit.
13. On all models, remove brake booster vacuum hose.
14. Extract master cylinder from vehicle.
15. On models with manual transaxles, remove clutch hose from brake/clutch reservoir.
16. On all models, remove master cylinder nuts and remove master cylinder.

To install, reverse removal procedure. Bleed brake system.

Please don't forget to rate:


Bleeding The Brake System Bleeding When any part of the hydraulic system has been disconnected for repair or replacement, air enters the lines causing spongy pedal action (because air can be compressed and brake fluid cannot). To correct this condition, it is necessary to bleed the hydraulic system to ensure all air is purged.
Always begin bleeding the brake system from the furthest wheel cylinder or caliper from the master cylinder; the right rear.
NOTE: The right side of the vehicle is the passenger side. The sides of the vehicle are determined from the driver's perspective. This reference is taken from sitting in the driver's seat, facing forward.
Maintain a full reservoir during the bleeding operation. Never use brake fluid that has been drained from the hydraulic system, or from an open container, no matter how clean it is. Always use brake fluid from a new, sealed container. The front and rear reservoir will drain as the front or rear brakes are bled.

1. Park the vehicle on a level surface. Place the vehicle in PARK (automatic) or REVERSE (manual) with the engine OFF, and apply the parking brake. Chock the rear wheels to prevent vehicle movement. NOTE: Wheel chocks may be purchased at your local auto parts store, or a block of wood cut into wedges may be used.
   
2. Loosen the lugnuts from all four wheels, but do not remove the lugnuts until the vehicle is raised and supported properly.
3. Use an approved jack and raise the vehicle high enough to place jack stands under all four corners of the vehicle. Place the jack stands under the frame or axles of the vehicle. Ensure that the front of the vehicle is raised higher than the rear.
4. Remove the wheels from the vehicle.
5. Clean all dirt from around the master cylinder fill cap. Remove the cap and fill the master cylinder with brake fluid until the level is within 1/4 in. (6mm) of the top edge of the reservoir.
6. Clean the bleeder screws at all four wheels. The bleeder screws are located on the back of the brake backing plate (drum brakes) and at the top of the brake calipers (disc brakes).
7. Attach a length of rubber hose over the bleeder screw and place the other end of the hose in a plastic jar.
8. Have an assistant place and hold pressure on the brake pedal.
9. Open the bleeder screw 1/2 - 3/4 turn. As the bleeder is opened, the brake pedal will travel to the floor. Have the assistant inform you when the pedal has bottomed out. NOTE: Do not remove pressure from the brake pedal once it is bottomed out. No movement to the pedal should occur until the bleeder is closed and the assistant is made aware of the situation. Failure to do this will draw more air into the system.
   
10. Close the bleeder screw and tell your assistant remove their foot from the brake pedal. Continue this process to purge all air from the system.
11. When bubbles cease to appear at the end of the bleeder hose, tighten the bleeder screw and remove the hose.
12. After bleeding each wheel, check the master cylinder fluid level and add fluid accordingly.
13. Repeat the bleeding operation at the remaining three wheels, ending with the one closet to the master cylinder. The pattern is, RR, LR, RF, LF.
14. Fill the master cylinder reservoir to the proper level and install the reservoir cap.